diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f3ce978..18f54dc5 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,10 +1,13 @@
-## 5.0.0
+## 5.0.0-nullsafety.0
 
+- Added support for Dart null-safety feature
+- Updated integration tests
 - Added Android Hybrid Composition support "Use PlatformViewLink widget for Android WebView" [#462](https://github.com/pichillilorenzo/flutter_inappwebview/pull/462) (thanks to [plateaukao](https://github.com/plateaukao) and [tneotia](https://github.com/tneotia))
 - Merge "Upgraded appcompat to 1.2.0-rc-02" [#465](https://github.com/pichillilorenzo/flutter_inappwebview/pull/465) (thanks to [andreidiaconu](https://github.com/andreidiaconu))
 - Merge "Added missing field 'headers' which returned by WebResourceResponse.toMap()" [#490](https://github.com/pichillilorenzo/flutter_inappwebview/pull/490) (thanks to [Doflatango](https://github.com/Doflatango))
 - Merge "Fix: added iOS fallback module import" [#466](https://github.com/pichillilorenzo/flutter_inappwebview/pull/466) (thanks to [Eddayy](https://github.com/Eddayy))
 - Merge "Fix NullPointerException after taking a photo by a camera app on Android" [#492](https://github.com/pichillilorenzo/flutter_inappwebview/pull/492) (thanks to [AAkira](https://github.com/AAkira))
+- Fixed missing properties initialization when using InAppWebViewController.fromInAppBrowser
 - Fixed "Issue in Flutter web: 'Unsupported operation: Platform._operatingSystem'" [#507](https://github.com/pichillilorenzo/flutter_inappwebview/issues/507)
 - Fixed "window.flutter_inappwebview.callHandler is not a function" [#218](https://github.com/pichillilorenzo/flutter_inappwebview/issues/218)
 - Fixed "Android ContentBlocker - java.lang.NullPointerException ContentBlockerTrigger resource type" [#506](https://github.com/pichillilorenzo/flutter_inappwebview/issues/506)
@@ -12,6 +15,11 @@
 - Fixed missing `clearHistory` webview method implementation on Android
 - Fixed iOS crash when using CookieManager getCookies for an URL and the host URL is `null`
 
+### BREAKING CHANGES
+
+- Minimum Flutter version required is `1.22.0` and Dart SDK `>=2.12.0-0 <3.0.0`
+- Removed `debuggingEnabled` WebView option; on Android you should use now the `AndroidInAppWebViewController.setWebContentsDebuggingEnabled(bool debuggingEnabled)` static method; on iOS, debugging is always enabled
+
 ## 4.0.0+4
 
 - Reverted calling `handler.post` on Android when a WebView is created
diff --git a/README.md b/README.md
index d398a02e..ea971ea9 100755
--- a/README.md
+++ b/README.md
@@ -22,8 +22,8 @@ A Flutter plugin that allows you to add an inline webview, to use an headless we
 
 ## Requirements
 
-- Dart sdk: ">=2.7.0 <3.0.0"
-- Flutter: ">=1.12.13+hotfix.5"
+- Dart sdk: ">=2.12.0-0 <3.0.0"
+- Flutter: ">=1.22.0"
 - Android: `minSdkVersion 17` and add support for `androidx` (see [AndroidX Migration](https://flutter.dev/docs/development/androidx-migration) to migrate an existing app)
 - iOS: `--ios-language swift`, Xcode version `>= 11`
 
@@ -75,6 +75,22 @@ or **Android API 19+** if you enable the `useHybridComposition` Android-specific
 - Check the official [Network security configuration - "Opt out of cleartext traffic"](https://developer.android.com/training/articles/security-config#CleartextTrafficPermitted) section.
 - Also, check this StackOverflow issue answer: [Cleartext HTTP traffic not permitted](https://stackoverflow.com/a/50834600/4637638).
 
+#### Debugging Android WebViews
+On Android, in order to enable/disable debugging WebViews using `chrome://inspect` on Chrome, you should use the `AndroidInAppWebViewController.setWebContentsDebuggingEnabled(bool debuggingEnabled)` static method.
+
+For example, you could call it inside the main function:
+```dart
+Future main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
+
+  runApp(new MyApp());
+}
+```
+
 ### IMPORTANT Note for iOS
 
 If you are starting a new fresh app, you need to create the Flutter App with `flutter create --androidx -i swift`
@@ -168,6 +184,9 @@ Add the following codes inside the `<application>` tag of your `android/app/src/
 </provider>
 ```
 
+#### Debugging iOS WebViews
+On iOS, debugging WebViews on Safari through developer tools is always enabled. There isn't a way to enable or disable it.
+
 ## Getting Started
 
 For help getting started with Flutter, view our online
@@ -241,11 +260,15 @@ Use `InAppWebViewController` to control the WebView instance.
 Example:
 ```dart
 import 'dart:async';
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
 Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
   runApp(new MyApp());
 }
 
@@ -256,7 +279,7 @@ class MyApp extends StatefulWidget {
 
 class _MyAppState extends State<MyApp> {
 
-  InAppWebViewController webView;
+  InAppWebViewController? webView;
   String url = "";
   double progress = 0;
 
@@ -278,81 +301,75 @@ class _MyAppState extends State<MyApp> {
           title: const Text('InAppWebView Example'),
         ),
         body: Container(
-          child: Column(children: <Widget>[
-            Container(
-              padding: EdgeInsets.all(20.0),
-              child: Text(
-                  "CURRENT URL\n${(url.length > 50) ? url.substring(0, 50) + "..." : url}"),
-            ),
-            Container(
-                padding: EdgeInsets.all(10.0),
-                child: progress < 1.0
-                    ? LinearProgressIndicator(value: progress)
-                    : Container()),
-            Expanded(
-              child: Container(
-                margin: const EdgeInsets.all(10.0),
-                decoration:
-                    BoxDecoration(border: Border.all(color: Colors.blueAccent)),
-                child: InAppWebView(
-                  initialUrl: "https://flutter.dev/",
-                  initialHeaders: {},
-                  initialOptions: InAppWebViewGroupOptions(
-                    crossPlatform: InAppWebViewOptions(
-                        debuggingEnabled: true,
-                    )
+            child: Column(children: <Widget>[
+              Container(
+                padding: EdgeInsets.all(20.0),
+                child: Text(
+                    "CURRENT URL\n${(url.length > 50) ? url.substring(0, 50) + "..." : url}"),
+              ),
+              Container(
+                  padding: EdgeInsets.all(10.0),
+                  child: progress < 1.0
+                      ? LinearProgressIndicator(value: progress)
+                      : Container()),
+              Expanded(
+                child: Container(
+                  margin: const EdgeInsets.all(10.0),
+                  decoration:
+                  BoxDecoration(border: Border.all(color: Colors.blueAccent)),
+                  child: InAppWebView(
+                    initialUrl: "https://flutter.dev/",
+                    initialHeaders: {},
+                    initialOptions: InAppWebViewGroupOptions(
+                        crossPlatform: InAppWebViewOptions(
+
+                        )
+                    ),
+                    onWebViewCreated: (InAppWebViewController controller) {
+                      webView = controller;
+                    },
+                    onLoadStart: (controller, url) {
+                      setState(() {
+                        this.url = url ?? '';
+                      });
+                    },
+                    onLoadStop: (controller, url) async {
+                      setState(() {
+                        this.url = url ?? '';
+                      });
+                    },
+                    onProgressChanged: (controller, progress) {
+                      setState(() {
+                        this.progress = progress / 100;
+                      });
+                    },
                   ),
-                  onWebViewCreated: (InAppWebViewController controller) {
-                    webView = controller;
-                  },
-                  onLoadStart: (InAppWebViewController controller, String url) {
-                    setState(() {
-                      this.url = url;
-                    });
-                  },
-                  onLoadStop: (InAppWebViewController controller, String url) async {
-                    setState(() {
-                      this.url = url;
-                    });
-                  },
-                  onProgressChanged: (InAppWebViewController controller, int progress) {
-                    setState(() {
-                      this.progress = progress / 100;
-                    });
-                  },
                 ),
               ),
-            ),
-            ButtonBar(
-              alignment: MainAxisAlignment.center,
-              children: <Widget>[
-                RaisedButton(
-                  child: Icon(Icons.arrow_back),
-                  onPressed: () {
-                    if (webView != null) {
-                      webView.goBack();
-                    }
-                  },
-                ),
-                RaisedButton(
-                  child: Icon(Icons.arrow_forward),
-                  onPressed: () {
-                    if (webView != null) {
-                      webView.goForward();
-                    }
-                  },
-                ),
-                RaisedButton(
-                  child: Icon(Icons.refresh),
-                  onPressed: () {
-                    if (webView != null) {
-                      webView.reload();
-                    }
-                  },
-                ),
-              ],
-            ),
-        ])),
+              ButtonBar(
+                alignment: MainAxisAlignment.center,
+                children: <Widget>[
+                  RaisedButton(
+                    child: Icon(Icons.arrow_back),
+                    onPressed: () {
+                      webView?.goBack();
+                    },
+                  ),
+                  RaisedButton(
+                    child: Icon(Icons.arrow_forward),
+                    onPressed: () {
+                      webView?.goForward();
+                    },
+                  ),
+                  RaisedButton(
+                    child: Icon(Icons.refresh),
+                    onPressed: () {
+                      webView?.reload();
+                    },
+                  ),
+                ],
+              ),
+            ])),
       ),
     );
   }
@@ -445,7 +462,7 @@ Methods available:
 
 ##### `InAppWebViewController` Android-specific methods
 
-Android-specific methods can be called using the `InAppWebViewController.android` attribute.
+Android-specific methods can be called using the `InAppWebViewController.android` attribute. Static methods can be called using the `AndroidInAppWebViewController` class directly.
 
 * `startSafeBrowsing`: Starts Safe Browsing initialization.
 * `clearSslPreferences`: Clears the SSL preferences table stored in response to proceeding with SSL certificate errors.
@@ -462,10 +479,11 @@ Android-specific methods can be called using the `InAppWebViewController.android
 * `static getSafeBrowsingPrivacyPolicyUrl`: Returns a URL pointing to the privacy policy for Safe Browsing reporting. This value will never be `null`.
 * `static setSafeBrowsingWhitelist({@required List<String> hosts})`: Sets the list of hosts (domain names/IP addresses) that are exempt from SafeBrowsing checks. The list is global for all the WebViews.
 * `static getCurrentWebViewPackage`: Gets the current Android WebView package info.
+* `static setWebContentsDebuggingEnabled(bool debuggingEnabled)`: Enables debugging of web contents (HTML / CSS / JavaScript) loaded into any WebViews of this application. Debugging is disabled by default.
 
 ##### `InAppWebViewController` iOS-specific methods
 
-iOS-specific methods can be called using the `InAppWebViewController.ios` attribute.
+iOS-specific methods can be called using the `InAppWebViewController.ios` attribute. Static methods can be called using the `IOSInAppWebViewController` class directly.
 
 * `hasOnlySecureContent`: A Boolean value indicating whether all resources on the page have been loaded over securely encrypted connections.
 * `reloadFromOrigin`: Reloads the current page, performing end-to-end revalidation using cache-validating conditionals if possible.
@@ -528,7 +546,6 @@ Instead, on the `onLoadStop` WebView event, you can use `callHandler` directly:
 * `userAgent`: Sets the user-agent for the WebView.
 * `applicationNameForUserAgent`: Append to the existing user-agent. Setting userAgent will override this.
 * `javaScriptEnabled`: Set to `true` to enable JavaScript. The default value is `true`.
-* `debuggingEnabled`: Enables debugging of web contents (HTML / CSS / JavaScript) loaded into any WebViews of this application.
 * `javaScriptCanOpenWindowsAutomatically`: Set to `true` to allow JavaScript open windows without user interaction. The default value is `false`.
 * `mediaPlaybackRequiresUserGesture`: Set to `true` to prevent HTML5 audio or video from autoplaying. The default value is `true`.
 * `minimumFontSize`: Sets the minimum font size. The default value is `8` for Android, `0` for iOS.
@@ -699,6 +716,9 @@ import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
 Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
   runApp(new MyApp());
 }
 
@@ -709,8 +729,8 @@ class MyApp extends StatefulWidget {
 
 class _MyAppState extends State<MyApp> {
 
-  InAppWebViewController webView;
-  ContextMenu contextMenu;
+  InAppWebViewController? webView;
+  ContextMenu? contextMenu;
   String url = "";
   double progress = 0;
 
@@ -727,7 +747,7 @@ class _MyAppState extends State<MyApp> {
         onCreateContextMenu: (hitTestResult) async {
           print("onCreateContextMenu");
           print(hitTestResult.extra);
-          print(await webView.getSelectedText());
+          print(await webView?.getSelectedText());
         },
         onHideContextMenu: () {
           print("onHideContextMenu");
@@ -775,23 +795,23 @@ class _MyAppState extends State<MyApp> {
                     initialHeaders: {},
                     initialOptions: InAppWebViewGroupOptions(
                         crossPlatform: InAppWebViewOptions(
-                          debuggingEnabled: true,
+
                         )
                     ),
                     onWebViewCreated: (InAppWebViewController controller) {
                       webView = controller;
                     },
-                    onLoadStart: (InAppWebViewController controller, String url) {
+                    onLoadStart: (controller, url) {
                       setState(() {
-                        this.url = url;
+                        this.url = url ?? '';
                       });
                     },
-                    onLoadStop: (InAppWebViewController controller, String url) async {
+                    onLoadStop: (controller, url) async {
                       setState(() {
-                        this.url = url;
+                        this.url = url ?? '';
                       });
                     },
-                    onProgressChanged: (InAppWebViewController controller, int progress) {
+                    onProgressChanged: (controller, progress) {
                       setState(() {
                         this.progress = progress / 100;
                       });
@@ -805,25 +825,19 @@ class _MyAppState extends State<MyApp> {
                   RaisedButton(
                     child: Icon(Icons.arrow_back),
                     onPressed: () {
-                      if (webView != null) {
-                        webView.goBack();
-                      }
+                      webView?.goBack();
                     },
                   ),
                   RaisedButton(
                     child: Icon(Icons.arrow_forward),
                     onPressed: () {
-                      if (webView != null) {
-                        webView.goForward();
-                      }
+                      webView?.goForward();
                     },
                   ),
                   RaisedButton(
                     child: Icon(Icons.refresh),
                     onPressed: () {
-                      if (webView != null) {
-                        webView.reload();
-                      }
+                      webView?.reload();
                     },
                   ),
                 ],
@@ -856,12 +870,16 @@ As `InAppWebView`, it has the same options and events. Use `InAppWebViewControll
 Example:
 ```dart
 import 'dart:async';
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
 Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
   runApp(new MyApp());
 }
 
@@ -872,7 +890,7 @@ class MyApp extends StatefulWidget {
 
 class _MyAppState extends State<MyApp> {
 
-  HeadlessInAppWebView headlessWebView;
+  HeadlessInAppWebView? headlessWebView;
   String url = "";
 
   @override
@@ -883,7 +901,7 @@ class _MyAppState extends State<MyApp> {
       initialUrl: "https://flutter.dev/",
       initialOptions: InAppWebViewGroupOptions(
         crossPlatform: InAppWebViewOptions(
-          debuggingEnabled: true,
+
         ),
       ),
       onWebViewCreated: (controller) {
@@ -895,19 +913,19 @@ class _MyAppState extends State<MyApp> {
       onLoadStart: (controller, url) async {
         print("onLoadStart $url");
         setState(() {
-          this.url = url;
+          this.url = url ?? '';
         });
       },
       onLoadStop: (controller, url) async {
         print("onLoadStop $url");
         setState(() {
-          this.url = url;
+          this.url = url ?? '';
         });
       },
-      onUpdateVisitedHistory: (InAppWebViewController controller, String url, bool androidIsReload) {
+      onUpdateVisitedHistory: (controller, url, androidIsReload) {
         print("onUpdateVisitedHistory $url");
         setState(() {
-          this.url = url;
+          this.url = url ?? '';
         });
       },
     );
@@ -916,7 +934,7 @@ class _MyAppState extends State<MyApp> {
   @override
   void dispose() {
     super.dispose();
-    headlessWebView.dispose();
+    headlessWebView?.dispose();
   }
 
   @override
@@ -936,8 +954,8 @@ class _MyAppState extends State<MyApp> {
               Center(
                 child: RaisedButton(
                     onPressed: () async {
-                      await headlessWebView.dispose();
-                      await headlessWebView.run();
+                      await headlessWebView?.dispose();
+                      await headlessWebView?.run();
                     },
                     child: Text("Run HeadlessInAppWebView")),
               ),
@@ -945,7 +963,7 @@ class _MyAppState extends State<MyApp> {
                 child: RaisedButton(
                     onPressed: () async {
                       try {
-                        await headlessWebView.webViewController.evaluateJavascript(source: """console.log('Here is the message!');""");
+                        await headlessWebView?.webViewController.evaluateJavascript(source: """console.log('Here is the message!');""");
                       } on MissingPluginException catch(e) {
                         print("HeadlessInAppWebView is not running. Click on \"Run HeadlessInAppWebView\"!");
                       }
@@ -955,7 +973,7 @@ class _MyAppState extends State<MyApp> {
               Center(
                 child: RaisedButton(
                     onPressed: () {
-                      headlessWebView.dispose();
+                      headlessWebView?.dispose();
                     },
                     child: Text("Dispose HeadlessInAppWebView")),
               )
@@ -975,6 +993,8 @@ In-App Browser using native WebView.
 Create a Class that extends the `InAppBrowser` Class in order to override the callbacks to manage the browser events.
 Example:
 ```dart
+import 'dart:io';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
@@ -985,22 +1005,22 @@ class MyInAppBrowser extends InAppBrowser {
   }
 
   @override
-  Future onLoadStart(String url) async {
+  Future onLoadStart(url) async {
     print("\n\nStarted $url\n\n");
   }
 
   @override
-  Future onLoadStop(String url) async {
+  Future onLoadStop(url) async {
     print("\n\nStopped $url\n\n");
   }
 
   @override
-  void onLoadError(String url, int code, String message) {
+  void onLoadError(url, code, message) {
     print("Can't load $url.. Error: $message");
   }
 
   @override
-  void onProgressChanged(int progress) {
+  void onProgressChanged(progress) {
     print("Progress: $progress");
   }
 
@@ -1022,7 +1042,7 @@ class MyInAppBrowser extends InAppBrowser {
         "ms ---> duration: " +
         response.duration.toString() +
         "ms " +
-        response.url);
+        (response.url ?? ''));
   }
 
   @override
@@ -1030,13 +1050,16 @@ class MyInAppBrowser extends InAppBrowser {
     print("""
     console output:
       message: ${consoleMessage.message}
-      messageLevel: ${consoleMessage.messageLevel.toValue()}
+      messageLevel: ${consoleMessage.messageLevel?.toValue()}
    """);
   }
 }
 
-void main() {
+Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
   runApp(
     new MyApp(),
   );
@@ -1044,7 +1067,7 @@ void main() {
 
 class MyApp extends StatefulWidget {
   final MyInAppBrowser browser = new MyInAppBrowser();
-  
+
   @override
   _MyAppState createState() => new _MyAppState();
 }
@@ -1147,23 +1170,25 @@ You can initialize the `ChromeSafariBrowser` instance with an `InAppBrowser` fal
 
 Create a Class that extends the `ChromeSafariBrowser` Class in order to override the callbacks to manage the browser events. Example:
 ```dart
+import 'dart:io';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
 class MyInAppBrowser extends InAppBrowser {
 
   @override
-  Future onLoadStart(String url) async {
+  Future onLoadStart(url) async {
     print("\n\nStarted $url\n\n");
   }
 
   @override
-  Future onLoadStop(String url) async {
+  Future onLoadStop(url) async {
     print("\n\nStopped $url\n\n");
   }
 
   @override
-  void onLoadError(String url, int code, String message) {
+  void onLoadError(url, code, message) {
     print("\n\nCan't load $url.. Error: $message\n\n");
   }
 
@@ -1194,11 +1219,12 @@ class MyChromeSafariBrowser extends ChromeSafariBrowser {
   }
 }
 
-void main() {
+Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
-  runApp(
-    new MyApp(),
-  );
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
+  runApp(new MyApp());
 }
 
 class MyApp extends StatefulWidget {
@@ -1308,6 +1334,9 @@ InAppLocalhostServer localhostServer = new InAppLocalhostServer();
 Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
   await localhostServer.start();
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
   runApp(new MyApp());
 }
 
@@ -1328,17 +1357,17 @@ Future main() async {
                   initialUrl: "http://localhost:8080/assets/index.html",
                   initialHeaders: {},
                   initialOptions: InAppWebViewGroupOptions(
-                      inAppWebViewOptions: InAppWebViewOptions(
-                        debuggingEnabled: true,
+                      crossPlatform: InAppWebViewOptions(
+
                       )
                   ),
-                  onWebViewCreated: (InAppWebViewController controller) {
+                  onWebViewCreated: (controller) {
   
                   },
-                  onLoadStart: (InAppWebViewController controller, String url) {
+                  onLoadStart: (controller, url) {
   
                   },
-                  onLoadStop: (InAppWebViewController controller, String url) {
+                  onLoadStop: (controller, url) {
   
                   },
                 ),
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/ContentBlocker/ContentBlockerHandler.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/ContentBlocker/ContentBlockerHandler.java
index fa245709..eee7b752 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/ContentBlocker/ContentBlockerHandler.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/ContentBlocker/ContentBlockerHandler.java
@@ -109,31 +109,33 @@ public class ContentBlockerHandler {
                     latch.await();
                 }
 
-                if (!trigger.loadType.isEmpty()) {
-                    URI cUrl = new URI(webViewUrl[0]);
-                    String cHost = cUrl.getHost();
-                    int cPort = cUrl.getPort();
-                    String cScheme = cUrl.getScheme();
+                if (webViewUrl[0] != null) {
+                    if (!trigger.loadType.isEmpty()) {
+                        URI cUrl = new URI(webViewUrl[0]);
+                        String cHost = cUrl.getHost();
+                        int cPort = cUrl.getPort();
+                        String cScheme = cUrl.getScheme();
 
-                    if ( (trigger.loadType.contains("first-party") && cHost != null && !(cScheme.equals(scheme) && cHost.equals(host) && cPort == port)) ||
-                            (trigger.loadType.contains("third-party") && cHost != null && cHost.equals(host)) )
-                        return null;
-                }
-                if (!trigger.ifTopUrl.isEmpty()) {
-                    boolean matchFound = false;
-                    for (String topUrl : trigger.ifTopUrl) {
-                        if (webViewUrl[0].startsWith(topUrl)) {
-                            matchFound = true;
-                            break;
-                        }
-                    }
-                    if (!matchFound)
-                        return null;
-                }
-                if (!trigger.unlessTopUrl.isEmpty()) {
-                    for (String topUrl : trigger.unlessTopUrl)
-                        if (webViewUrl[0].startsWith(topUrl))
+                        if ( (trigger.loadType.contains("first-party") && cHost != null && !(cScheme.equals(scheme) && cHost.equals(host) && cPort == port)) ||
+                                (trigger.loadType.contains("third-party") && cHost != null && cHost.equals(host)) )
                             return null;
+                    }
+                    if (!trigger.ifTopUrl.isEmpty()) {
+                        boolean matchFound = false;
+                        for (String topUrl : trigger.ifTopUrl) {
+                            if (webViewUrl[0].startsWith(topUrl)) {
+                                matchFound = true;
+                                break;
+                            }
+                        }
+                        if (!matchFound)
+                            return null;
+                    }
+                    if (!trigger.unlessTopUrl.isEmpty()) {
+                        for (String topUrl : trigger.unlessTopUrl)
+                            if (webViewUrl[0].startsWith(topUrl))
+                                return null;
+                    }
                 }
 
                 switch (action.type) {
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/FlutterWebView.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/FlutterWebView.java
index 912afd67..a59c6a95 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/FlutterWebView.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/FlutterWebView.java
@@ -67,28 +67,9 @@ public class FlutterWebView implements PlatformView, MethodCallHandler  {
               "- See the official wiki here: https://github.com/flutter/flutter/wiki/Upgrading-pre-1.12-Android-projects\n\n\n");
     }
 
-    // MutableContextWrapper mMutableContext = new MutableContextWrapper(Shared.activity);
-    // webView = new InAppWebView(mMutableContext, this, id, options, contextMenu, containerView);
-    // displayListenerProxy.onPostWebViewInitialization(displayManager);
-    // mMutableContext.setBaseContext(context);
-
-    webView = new InAppWebView(Shared.activity, this, id, windowId, options, contextMenu, containerView);
+    webView = new InAppWebView(context, this, id, windowId, options, contextMenu, containerView);
     displayListenerProxy.onPostWebViewInitialization(displayManager);
 
-    // fix https://github.com/pichillilorenzo/flutter_inappwebview/issues/182
-    try {
-      Class superClass =  webView.getClass().getSuperclass();
-      while(!superClass.getName().equals("android.view.View")) {
-        superClass = superClass.getSuperclass();
-      }
-      Field mContext = superClass.getDeclaredField("mContext");
-      mContext.setAccessible(true);
-      mContext.set(webView, context);
-    } catch (Exception e) {
-      e.printStackTrace();
-      Log.e(LOG_TAG, "Cannot find mContext for this WebView");
-    }
-
     webView.prepare();
 
     if (windowId != null) {
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebView.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebView.java
index d985344a..fb3a5dbe 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebView.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebView.java
@@ -677,9 +677,6 @@ final public class InAppWebView extends InputAwareWebView {
     WebSettings settings = getSettings();
 
     settings.setJavaScriptEnabled(options.javaScriptEnabled);
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
-      setWebContentsDebuggingEnabled(options.debuggingEnabled);
-    }
     settings.setJavaScriptCanOpenWindowsAutomatically(options.javaScriptCanOpenWindowsAutomatically);
     settings.setBuiltInZoomControls(options.builtInZoomControls);
     settings.setDisplayZoomControls(options.displayZoomControls);
@@ -853,7 +850,7 @@ final public class InAppWebView extends InputAwareWebView {
       }
     };
 
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && !options.useHybridComposition) {
       checkContextMenuShouldBeClosedTask = new Runnable() {
         @Override
         public void run() {
@@ -1133,9 +1130,6 @@ final public class InAppWebView extends InputAwareWebView {
     if (newOptionsMap.get("javaScriptEnabled") != null && options.javaScriptEnabled != newOptions.javaScriptEnabled)
       settings.setJavaScriptEnabled(newOptions.javaScriptEnabled);
 
-    if (newOptionsMap.get("debuggingEnabled") != null && options.debuggingEnabled != newOptions.debuggingEnabled && Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT)
-      setWebContentsDebuggingEnabled(newOptions.debuggingEnabled);
-
     if (newOptionsMap.get("useShouldInterceptAjaxRequest") != null && options.useShouldInterceptAjaxRequest != newOptions.useShouldInterceptAjaxRequest) {
       String placeholderValue = newOptions.useShouldInterceptAjaxRequest ? "true" : "false";
       String sourceJs = InAppWebView.enableVariableForShouldInterceptAjaxRequestJS.replace("$PLACEHOLDER_VALUE", placeholderValue);
@@ -1505,14 +1499,11 @@ final public class InAppWebView extends InputAwareWebView {
   }
 
   @Override
-  protected void onScrollChanged (int l,
-                                  int t,
-                                  int oldl,
-                                  int oldt) {
-    super.onScrollChanged(l, t, oldl, oldt);
-
-    int x = (int) (l/scale);
-    int y = (int) (t/scale);
+  protected void onScrollChanged (int x,
+                                  int y,
+                                  int oldX,
+                                  int oldY) {
+    super.onScrollChanged(x, y, oldX, oldY);
 
     if (floatingContextMenu != null) {
       floatingContextMenu.setAlpha(0f);
@@ -1662,12 +1653,18 @@ final public class InAppWebView extends InputAwareWebView {
 
   @Override
   public ActionMode startActionMode(ActionMode.Callback callback) {
+    if (options.useHybridComposition && !options.disableContextMenu && (contextMenu == null || contextMenu.keySet().size() == 0)) {
+      return super.startActionMode(callback);
+    }
     return rebuildActionMode(super.startActionMode(callback), callback);
   }
 
   @RequiresApi(api = Build.VERSION_CODES.M)
   @Override
   public ActionMode startActionMode(ActionMode.Callback callback, int type) {
+    if (options.useHybridComposition && !options.disableContextMenu && (contextMenu == null || contextMenu.keySet().size() == 0)) {
+      return super.startActionMode(callback, type);
+    }
     return rebuildActionMode(super.startActionMode(callback, type), callback);
   }
 
@@ -1711,6 +1708,7 @@ final public class InAppWebView extends InputAwareWebView {
         final MenuItem menuItem = actionMenu.getItem(i);
         final int itemId = menuItem.getItemId();
         final String itemTitle = menuItem.getTitle().toString();
+
         TextView text = (TextView) LayoutInflater.from(this.getContext())
                 .inflate(R.layout.floating_action_mode_item, this, false);
         text.setText(itemTitle);
@@ -1855,7 +1853,7 @@ final public class InAppWebView extends InputAwareWebView {
             "    var clientRect = range.getClientRects();" +
             "    if (clientRect.length > 0) {" +
             "      rangeY = clientRect[0].y;" +
-            "    } else if (document.activeElement) {" +
+            "    } else if (document.activeElement != null && document.activeElement.tagName.toLowerCase() !== 'iframe') {" +
             "      var boundingClientRect = document.activeElement.getBoundingClientRect();" +
             "      rangeY = boundingClientRect.y;" +
             "    }" +
@@ -1865,7 +1863,7 @@ final public class InAppWebView extends InputAwareWebView {
       @Override
       public void onReceiveValue(String value) {
         if (floatingContextMenu != null) {
-          if (value != null) {
+          if (value != null && !value.equals("null")) {
             int x = contextMenuPoint.x;
             int y = (int) ((Float.parseFloat(value) * scale) + (floatingContextMenu.getHeight() / 3.5));
             contextMenuPoint.y = y;
@@ -1873,6 +1871,7 @@ final public class InAppWebView extends InputAwareWebView {
           } else {
             floatingContextMenu.setVisibility(View.VISIBLE);
             floatingContextMenu.animate().alpha(1f).setDuration(100).setListener(null);
+            onFloatingActionGlobalLayout(contextMenuPoint.x, contextMenuPoint.y);
           }
         }
       }
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewClient.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewClient.java
index ea62d7f0..dd7ca586 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewClient.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewClient.java
@@ -176,7 +176,9 @@ public class InAppWebViewClient extends WebViewClient {
     if (webView.options.useOnLoadResource) {
       js += InAppWebView.resourceObserverJS.replaceAll("[\r\n]+", "");
     }
-    js += InAppWebView.checkGlobalKeyDownEventToHideContextMenuJS.replaceAll("[\r\n]+", "");
+    if (!webView.options.useHybridComposition) {
+      js += InAppWebView.checkGlobalKeyDownEventToHideContextMenuJS.replaceAll("[\r\n]+", "");
+    }
     js += InAppWebView.onWindowFocusEventJS.replaceAll("[\r\n]+", "");
     js += InAppWebView.onWindowBlurEventJS.replaceAll("[\r\n]+", "");
     js += InAppWebView.printJS.replaceAll("[\r\n]+", "");
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewOptions.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewOptions.java
index a40098fa..e3bb4fde 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewOptions.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InAppWebViewOptions.java
@@ -26,7 +26,6 @@ public class InAppWebViewOptions implements Options<InAppWebView> {
   public String userAgent = "";
   public String applicationNameForUserAgent = "";
   public Boolean javaScriptEnabled = true;
-  public Boolean debuggingEnabled = false;
   public Boolean javaScriptCanOpenWindowsAutomatically = false;
   public Boolean mediaPlaybackRequiresUserGesture = true;
   public Integer minimumFontSize = 8;
@@ -97,6 +96,7 @@ public class InAppWebViewOptions implements Options<InAppWebView> {
   public Boolean useShouldInterceptRequest = false;
   public Boolean useOnRenderProcessGone = false;
   public Boolean disableDefaultErrorPage = false;
+  public Boolean useHybridComposition = false;
 
   @Override
   public InAppWebViewOptions parse(Map<String, Object> options) {
@@ -129,9 +129,6 @@ public class InAppWebViewOptions implements Options<InAppWebView> {
         case "javaScriptEnabled":
           javaScriptEnabled = (Boolean) value;
           break;
-        case "debuggingEnabled":
-          debuggingEnabled = (Boolean) value;
-          break;
         case "javaScriptCanOpenWindowsAutomatically":
           javaScriptCanOpenWindowsAutomatically = (Boolean) value;
           break;
@@ -339,6 +336,9 @@ public class InAppWebViewOptions implements Options<InAppWebView> {
         case "disableDefaultErrorPage":
           disableDefaultErrorPage = (Boolean) value;
           break;
+        case "useHybridComposition":
+          useHybridComposition = (Boolean) value;
+          break;
       }
     }
 
@@ -355,7 +355,6 @@ public class InAppWebViewOptions implements Options<InAppWebView> {
     options.put("userAgent", userAgent);
     options.put("applicationNameForUserAgent", applicationNameForUserAgent);
     options.put("javaScriptEnabled", javaScriptEnabled);
-    options.put("debuggingEnabled", debuggingEnabled);
     options.put("javaScriptCanOpenWindowsAutomatically", javaScriptCanOpenWindowsAutomatically);
     options.put("mediaPlaybackRequiresUserGesture", mediaPlaybackRequiresUserGesture);
     options.put("minimumFontSize", minimumFontSize);
@@ -425,6 +424,7 @@ public class InAppWebViewOptions implements Options<InAppWebView> {
     options.put("useShouldInterceptRequest", useShouldInterceptRequest);
     options.put("useOnRenderProcessGone", useOnRenderProcessGone);
     options.put("disableDefaultErrorPage", disableDefaultErrorPage);
+    options.put("useHybridComposition", useHybridComposition);
     return options;
   }
 
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InputAwareWebView.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InputAwareWebView.java
index 24f77f4d..6a69a084 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InputAwareWebView.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebView/InputAwareWebView.java
@@ -16,6 +16,8 @@ import android.widget.ListPopupWindow;
  * A WebView subclass that mirrors the same implementation hacks that the system WebView does in
  * order to correctly create an InputConnection.
  *
+ * These hacks are only needed in Android versions below N and exist to create an InputConnection
+ * on the WebView's dedicated input, or IME, thread. The majority of this proxying logic is in
  * https://github.com/flutter/plugins/blob/master/packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/InputAwareWebView.java
  */
 public class InputAwareWebView extends WebView {
@@ -234,9 +236,9 @@ public class InputAwareWebView extends WebView {
 
   private boolean isCalledFromListPopupWindowShow() {
     StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
-    for (int i = 0; i < stackTraceElements.length; i++) {
-      if (stackTraceElements[i].getClassName().equals(ListPopupWindow.class.getCanonicalName())
-              && stackTraceElements[i].getMethodName().equals("show")) {
+    for (StackTraceElement stackTraceElement : stackTraceElements) {
+      if (stackTraceElement.getClassName().equals(ListPopupWindow.class.getCanonicalName())
+              && stackTraceElement.getMethodName().equals("show")) {
         return true;
       }
     }
diff --git a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebViewStatic.java b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebViewStatic.java
index a9744e28..db74d146 100755
--- a/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebViewStatic.java
+++ b/android/src/main/java/com/pichillilorenzo/flutter_inappwebview/InAppWebViewStatic.java
@@ -72,6 +72,13 @@ public class InAppWebViewStatic implements MethodChannel.MethodCallHandler {
           result.success(null);
         }
         break;
+      case "setWebContentsDebuggingEnabled":
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+          boolean debuggingEnabled = (boolean) call.argument("debuggingEnabled");
+          WebView.setWebContentsDebuggingEnabled(debuggingEnabled);
+        }
+        result.success(true);
+        break;
       default:
         result.notImplemented();
     }
diff --git a/example/.flutter-plugins-dependencies b/example/.flutter-plugins-dependencies
old mode 100755
new mode 100644
index 6f9ab3d4..9cebde9e
--- a/example/.flutter-plugins-dependencies
+++ b/example/.flutter-plugins-dependencies
@@ -1 +1 @@
-{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"e2e","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/e2e-0.2.4+4/","dependencies":[]},{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.4.4/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-1.6.10/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.0.1/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-5.4.11/","dependencies":[]}],"android":[{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"e2e","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/e2e-0.2.4+4/","dependencies":[]},{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.4.4/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-1.6.10/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.0.1/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-5.4.11/","dependencies":[]}],"macos":[{"name":"path_provider_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_macos-0.0.4+3/","dependencies":[]},{"name":"url_launcher_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_macos-0.0.1+7/","dependencies":[]}],"linux":[{"name":"path_provider_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_linux-0.0.1+1/","dependencies":[]}],"windows":[],"web":[{"name":"url_launcher_web","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_web-0.1.2/","dependencies":[]}]},"dependencyGraph":[{"name":"flutter_inappwebview","dependencies":[]},{"name":"e2e","dependencies":[]},{"name":"flutter_downloader","dependencies":[]},{"name":"path_provider","dependencies":["path_provider_macos","path_provider_linux"]},{"name":"path_provider_linux","dependencies":[]},{"name":"path_provider_macos","dependencies":[]},{"name":"permission_handler","dependencies":[]},{"name":"url_launcher","dependencies":["url_launcher_web","url_launcher_macos"]},{"name":"url_launcher_macos","dependencies":[]},{"name":"url_launcher_web","dependencies":[]}],"date_created":"2020-09-07 18:06:16.830498","version":"1.20.3"}
\ No newline at end of file
+{"info":"This is a generated file; do not edit or check into version control.","plugins":{"ios":[{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.5.2/","dependencies":[]},{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"integration_test","path":"/Users/lorenzopichilli/flutter/.pub-cache/git/plugins-16f3281b04b0db12e609352b1c9544901392e428/packages/integration_test/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-1.6.27/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.0.1+1/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-6.0.0-nullsafety.4/","dependencies":[]}],"android":[{"name":"flutter_downloader","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_downloader-1.5.2/","dependencies":[]},{"name":"flutter_inappwebview","path":"/Users/lorenzopichilli/Desktop/flutter_inappwebview/","dependencies":[]},{"name":"integration_test","path":"/Users/lorenzopichilli/flutter/.pub-cache/git/plugins-16f3281b04b0db12e609352b1c9544901392e428/packages/integration_test/","dependencies":[]},{"name":"path_provider","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider-1.6.27/","dependencies":[]},{"name":"permission_handler","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/permission_handler-5.0.1+1/","dependencies":[]},{"name":"url_launcher","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher-6.0.0-nullsafety.4/","dependencies":[]}],"macos":[{"name":"path_provider_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_macos-0.0.4+8/","dependencies":[]},{"name":"url_launcher_macos","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_macos-0.1.0-nullsafety.2/","dependencies":[]}],"linux":[{"name":"path_provider_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_linux-0.0.1+2/","dependencies":[]},{"name":"url_launcher_linux","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_linux-0.1.0-nullsafety.3/","dependencies":[]}],"windows":[{"name":"path_provider_windows","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/path_provider_windows-0.0.4+3/","dependencies":[]},{"name":"url_launcher_windows","path":"/Users/lorenzopichilli/flutter/.pub-cache/hosted/pub.dartlang.org/url_launcher_windows-0.1.0-nullsafety.2/","dependencies":[]}],"web":[]},"dependencyGraph":[{"name":"flutter_downloader","dependencies":[]},{"name":"flutter_inappwebview","dependencies":[]},{"name":"integration_test","dependencies":[]},{"name":"path_provider","dependencies":["path_provider_macos","path_provider_linux","path_provider_windows"]},{"name":"path_provider_linux","dependencies":[]},{"name":"path_provider_macos","dependencies":[]},{"name":"path_provider_windows","dependencies":[]},{"name":"permission_handler","dependencies":[]},{"name":"url_launcher","dependencies":["url_launcher_linux","url_launcher_macos","url_launcher_windows"]},{"name":"url_launcher_linux","dependencies":[]},{"name":"url_launcher_macos","dependencies":[]},{"name":"url_launcher_windows","dependencies":[]}],"date_created":"2021-01-28 16:30:24.941683","version":"1.26.0-13.0.pre.194"}
\ No newline at end of file
diff --git a/example/android/app/src/main/java/com/pichillilorenzo/flutterwebviewexample/EmbedderV1Activity.java b/example/android/app/src/main/java/com/pichillilorenzo/flutterwebviewexample/EmbedderV1Activity.java
index f1d74591..6ef55096 100755
--- a/example/android/app/src/main/java/com/pichillilorenzo/flutterwebviewexample/EmbedderV1Activity.java
+++ b/example/android/app/src/main/java/com/pichillilorenzo/flutterwebviewexample/EmbedderV1Activity.java
@@ -1,15 +1,16 @@
 package com.pichillilorenzo.flutterwebviewexample;
 
 import android.os.Bundle;
-import dev.flutter.plugins.e2e.E2EPlugin;
-import io.flutter.app.FlutterActivity;
+import dev.flutter.plugins.integration_test.IntegrationTestPlugin;
 import com.pichillilorenzo.flutter_inappwebview.InAppWebViewFlutterPlugin;
 
-public class EmbedderV1Activity extends FlutterActivity {
+@SuppressWarnings("deprecation")
+public class EmbedderV1Activity extends io.flutter.app.FlutterActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
-    E2EPlugin.registerWith(registrarFor("dev.flutter.plugins.e2e.E2EPlugin"));
+    IntegrationTestPlugin.registerWith(
+            registrarFor("dev.flutter.plugins.integration_test.IntegrationTestPlugin"));
     InAppWebViewFlutterPlugin.registerWith(
             registrarFor("com.pichillilorenzo.flutter_inappwebview.InAppWebViewFlutterPlugin"));
   }
diff --git a/example/assets/sample_audio.ogg b/example/assets/sample_audio.ogg
new file mode 100644
index 00000000..27e17104
Binary files /dev/null and b/example/assets/sample_audio.ogg differ
diff --git a/example/assets/sample_video.mp4 b/example/assets/sample_video.mp4
new file mode 100644
index 00000000..a203d0cd
Binary files /dev/null and b/example/assets/sample_video.mp4 differ
diff --git a/example/integration_test/.env.dart b/example/integration_test/.env.dart
new file mode 100755
index 00000000..43e66331
--- /dev/null
+++ b/example/integration_test/.env.dart
@@ -0,0 +1 @@
+final environment = {"NODE_SERVER_IP":"192.168.1.129"};
\ No newline at end of file
diff --git a/example/integration_test/webview_flutter_test.dart b/example/integration_test/webview_flutter_test.dart
new file mode 100644
index 00000000..3d9114e3
--- /dev/null
+++ b/example/integration_test/webview_flutter_test.dart
@@ -0,0 +1,2052 @@
+// @dart = 2.9
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+
+import '.env.dart';
+
+class Foo {
+  String bar;
+  String baz;
+
+  Foo({this.bar, this.baz});
+
+  Map<String, dynamic> toJson() {
+    return {
+      'bar': this.bar,
+      'baz': this.baz
+    };
+  }
+}
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  if (Platform.isAndroid) {
+    AndroidInAppWebViewController.setWebContentsDebuggingEnabled(false);
+  }
+
+  testWidgets('initialUrl', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    final String currentUrl = await controller.getUrl();
+    expect(currentUrl, 'https://flutter.dev/');
+  });
+
+  testWidgets('loadUrl', (WidgetTester tester) async {
+    final Completer controllerCompleter =
+    Completer<InAppWebViewController>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await controller.loadUrl(url: 'https://www.google.com/');
+    final String currentUrl = await controller.getUrl();
+    expect(currentUrl, 'https://www.google.com/');
+  });
+
+  // enable this once https://github.com/flutter/flutter/issues/31510
+  // is resolved.
+  testWidgets('loadUrl with headers', (WidgetTester tester) async {
+    final Completer controllerCompleter =
+    Completer<InAppWebViewController>();
+    final StreamController<String> pageStarts = StreamController<String>();
+    final StreamController<String> pageLoads = StreamController<String>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          initialOptions: InAppWebViewGroupOptions(
+            crossPlatform: InAppWebViewOptions(
+              javaScriptEnabled: true
+            )
+          ),
+          onLoadStart: (controller, url) {
+            pageStarts.add(url);
+          },
+          onLoadStop: (controller, url) {
+            pageLoads.add(url);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    final Map<String, String> headers = <String, String>{
+      'test_header': 'flutter_test_header'
+    };
+    await controller.loadUrl(url: 'https://flutter-header-echo.herokuapp.com/',
+        headers: headers);
+    final String currentUrl = await controller.getUrl();
+    expect(currentUrl, 'https://flutter-header-echo.herokuapp.com/');
+
+    await pageStarts.stream.firstWhere((String url) => url == currentUrl);
+    await pageLoads.stream.firstWhere((String url) => url == currentUrl);
+
+    final String content = await controller
+        .evaluateJavascript(source: 'document.documentElement.innerText');
+    expect(content.contains('flutter_test_header'), isTrue);
+  });
+
+  testWidgets('JavaScript Handler', (WidgetTester tester) async {
+
+    final Completer controllerCompleter =
+    Completer<InAppWebViewController>();
+    final Completer<void> pageStarted = Completer<void>();
+    final Completer<void> pageLoaded = Completer<void>();
+    final Completer<void> handlerFoo = Completer<void>();
+    final Completer<void> handlerFooWithArgs = Completer<void>();
+    final List<dynamic> messagesReceived = <dynamic>[];
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_javascript_handler_test.html",
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+
+            controller.addJavaScriptHandler(handlerName:'handlerFoo', callback: (args) {
+              handlerFoo.complete();
+              return Foo(bar: 'bar_value', baz: 'baz_value');
+            });
+
+            controller.addJavaScriptHandler(handlerName: 'handlerFooWithArgs', callback: (args) {
+              messagesReceived.add(args[0] as int);
+              messagesReceived.add(args[1] as bool);
+              messagesReceived.add(args[2].cast<dynamic>());
+              messagesReceived.add(args[3].cast<String, String>());
+              messagesReceived.add(args[4].cast<String, String>());
+              handlerFooWithArgs.complete();
+            });
+          },
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true
+              )
+          ),
+          onLoadStart: (controller, url) {
+            pageStarted.complete();
+          },
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageStarted.future;
+    await pageLoaded.future;
+    await handlerFoo.future;
+    await handlerFooWithArgs.future;
+
+    expect(messagesReceived[0], 1);
+    expect(messagesReceived[1], true);
+    expect(listEquals(messagesReceived[2], ["bar", 5]), true);
+    expect(mapEquals(messagesReceived[3], {"foo": "baz"}), true);
+    expect(mapEquals(messagesReceived[4], {"bar":"bar_value","baz":"baz_value"}), true);
+  });
+
+  testWidgets('resize webview', (WidgetTester tester) async {
+    final String resizeTest = '''
+        <!DOCTYPE html><html>
+        <head><title>Resize test</title>
+          <script type="text/javascript">
+            function onResize() {
+              window.flutter_inappwebview.callHandler('resize')
+            }
+            function onLoad() {
+              window.onresize = onResize;
+            }
+          </script>
+        </head>
+        <body onload="onLoad();" bgColor="blue">
+        </body>
+        </html>
+      ''';
+    final String resizeTestBase64 =
+    base64Encode(const Utf8Encoder().convert(resizeTest));
+    final Completer<void> resizeCompleter = Completer<void>();
+    final Completer<void> pageStarted = Completer<void>();
+    final Completer<void> pageLoaded = Completer<void>();
+    final Completer controllerCompleter =
+    Completer<InAppWebViewController>();
+    final GlobalKey key = GlobalKey();
+
+    final InAppWebView webView = InAppWebView(
+      key: key,
+      initialUrl: 'data:text/html;charset=utf-8;base64,$resizeTestBase64',
+      onWebViewCreated: (controller) {
+        controllerCompleter.complete(controller);
+
+        controller.addJavaScriptHandler(handlerName:'resize', callback: (args) {
+          resizeCompleter.complete(true);
+        });
+      },
+      onLoadStart: (controller, url) {
+        pageStarted.complete();
+      },
+      onLoadStop: (controller, url) {
+        pageLoaded.complete();
+      },
+      initialOptions: InAppWebViewGroupOptions(
+          crossPlatform: InAppWebViewOptions(
+              javaScriptEnabled: true
+          )
+      ),
+    );
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: Column(
+          children: <Widget>[
+            SizedBox(
+              width: 200,
+              height: 200,
+              child: webView,
+            ),
+          ],
+        ),
+      ),
+    );
+
+    await controllerCompleter.future;
+    await pageStarted.future;
+    await pageLoaded.future;
+
+    expect(resizeCompleter.isCompleted, false);
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: Column(
+          children: <Widget>[
+            SizedBox(
+              width: 400,
+              height: 400,
+              child: webView,
+            ),
+          ],
+        ),
+      ),
+    );
+
+    await resizeCompleter.future;
+  });
+
+  testWidgets('set custom userAgent', (WidgetTester tester) async {
+    final Completer controllerCompleter1 =
+    Completer<InAppWebViewController>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          initialUrl: 'about:blank',
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  userAgent: 'Custom_User_Agent1',
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter1.complete(controller);
+          },
+        ),
+      ),
+    );
+    InAppWebViewController controller1 = await controllerCompleter1.future;
+    final String customUserAgent1 = await controller1.evaluateJavascript(source: 'navigator.userAgent;');
+    expect(customUserAgent1, 'Custom_User_Agent1');
+
+    await controller1.setOptions(options: InAppWebViewGroupOptions(
+        crossPlatform: InAppWebViewOptions(
+          userAgent: 'Custom_User_Agent2',
+        )
+    ));
+
+    final String customUserAgent2 = await controller1.evaluateJavascript(source: 'navigator.userAgent;');
+    expect(customUserAgent2, 'Custom_User_Agent2');
+  });
+
+  group('Video playback policy', () {
+    String videoTestBase64;
+    setUpAll(() async {
+      final ByteData videoData =
+      await rootBundle.load('test_assets/sample_video.mp4');
+      final String base64VideoData =
+      base64Encode(Uint8List.view(videoData.buffer));
+      final String videoTest = '''
+        <!DOCTYPE html><html>
+        <head><title>Video auto play</title>
+          <script type="text/javascript">
+            function play() {
+              var video = document.getElementById("video");
+              video.play();
+            }
+            function isPaused() {
+              var video = document.getElementById("video");
+              return video.paused;
+            }
+            function isFullScreen() {
+              var video = document.getElementById("video");
+              return video.webkitDisplayingFullscreen;
+            }
+          </script>
+        </head>
+        <body onload="play();">
+        <video controls playsinline autoplay id="video">
+          <source src="data:video/mp4;charset=utf-8;base64,$base64VideoData">
+        </video>
+        </body>
+        </html>
+      ''';
+      videoTestBase64 = base64Encode(const Utf8Encoder().convert(videoTest));
+    });
+
+    testWidgets('Auto media playback', (WidgetTester tester) async {
+      Completer<InAppWebViewController> controllerCompleter =
+      Completer<InAppWebViewController>();
+      Completer<void> pageLoaded = Completer<void>();
+
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: 'data:text/html;charset=utf-8;base64,$videoTestBase64',
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+                crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  mediaPlaybackRequiresUserGesture: false
+                )
+            ),
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+          ),
+        ),
+      );
+      InAppWebViewController controller = await controllerCompleter.future;
+      await pageLoaded.future;
+
+      bool isPaused = await controller.evaluateJavascript(source: 'isPaused();');
+      expect(isPaused, false);
+
+      controllerCompleter = Completer<InAppWebViewController>();
+      pageLoaded = Completer<void>();
+
+      // We change the key to re-create a new webview as we change the mediaPlaybackRequiresUserGesture
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: 'data:text/html;charset=utf-8;base64,$videoTestBase64',
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+                crossPlatform: InAppWebViewOptions(
+                    javaScriptEnabled: true,
+                    mediaPlaybackRequiresUserGesture: true
+                )
+            ),
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+          ),
+        ),
+      );
+
+      controller = await controllerCompleter.future;
+      await pageLoaded.future;
+
+      isPaused = await controller.evaluateJavascript(source: 'isPaused();');
+      expect(isPaused, true);
+    });
+
+    testWidgets('Video plays inline when allowsInlineMediaPlayback is true',
+            (WidgetTester tester) async {
+          Completer<InAppWebViewController> controllerCompleter =
+          Completer<InAppWebViewController>();
+          Completer<void> pageLoaded = Completer<void>();
+
+          await tester.pumpWidget(
+            Directionality(
+              textDirection: TextDirection.ltr,
+              child: InAppWebView(
+                key: GlobalKey(),
+                initialUrl: 'data:text/html;charset=utf-8;base64,$videoTestBase64',
+                onWebViewCreated: (controller) {
+                  controllerCompleter.complete(controller);
+                },
+                initialOptions: InAppWebViewGroupOptions(
+                    crossPlatform: InAppWebViewOptions(
+                        javaScriptEnabled: true,
+                        mediaPlaybackRequiresUserGesture: false,
+                    ),
+                  ios: IOSInAppWebViewOptions(
+                    allowsInlineMediaPlayback: true
+                  )
+                ),
+                onLoadStop: (controller, url) {
+                  pageLoaded.complete();
+                },
+              ),
+            ),
+          );
+          InAppWebViewController controller = await controllerCompleter.future;
+          await pageLoaded.future;
+
+          bool isFullScreen =
+          await controller.evaluateJavascript(source: 'isFullScreen();');
+          expect(isFullScreen, false);
+        });
+
+    testWidgets('Video plays fullscreen when allowsInlineMediaPlayback is false',
+            (WidgetTester tester) async {
+          Completer<InAppWebViewController> controllerCompleter =
+          Completer<InAppWebViewController>();
+          Completer<void> pageLoaded = Completer<void>();
+
+          await tester.pumpWidget(
+            Directionality(
+              textDirection: TextDirection.ltr,
+              child: InAppWebView(
+                key: GlobalKey(),
+                initialUrl: 'data:text/html;charset=utf-8;base64,$videoTestBase64',
+                onWebViewCreated: (controller) {
+                  controllerCompleter.complete(controller);
+                },
+                initialOptions: InAppWebViewGroupOptions(
+                    crossPlatform: InAppWebViewOptions(
+                      javaScriptEnabled: true,
+                      mediaPlaybackRequiresUserGesture: false,
+                    ),
+                    ios: IOSInAppWebViewOptions(
+                        allowsInlineMediaPlayback: false
+                    )
+                ),
+                onLoadStop: (controller, url) {
+                  pageLoaded.complete();
+                },
+              ),
+            ),
+          );
+
+          InAppWebViewController controller = await controllerCompleter.future;
+          await pageLoaded.future;
+
+          bool isFullScreen = await controller.evaluateJavascript(source: 'isFullScreen();');
+          expect(isFullScreen, true);
+        }, skip: true /*https://github.com/flutter/flutter/issues/72572 */);
+  });
+
+  group('Audio playback policy', () {
+    String audioTestBase64;
+    setUpAll(() async {
+      final ByteData audioData =
+      await rootBundle.load('test_assets/sample_audio.ogg');
+      final String base64AudioData =
+      base64Encode(Uint8List.view(audioData.buffer));
+      final String audioTest = '''
+        <!DOCTYPE html><html>
+        <head><title>Audio auto play</title>
+          <script type="text/javascript">
+            function play() {
+              var audio = document.getElementById("audio");
+              audio.play();
+            }
+            function isPaused() {
+              var audio = document.getElementById("audio");
+              return audio.paused;
+            }
+          </script>
+        </head>
+        <body onload="play();">
+        <audio controls id="audio">
+          <source src="data:audio/ogg;charset=utf-8;base64,$base64AudioData">
+        </audio>
+        </body>
+        </html>
+      ''';
+      audioTestBase64 = base64Encode(const Utf8Encoder().convert(audioTest));
+    });
+
+    testWidgets('Auto media playback', (WidgetTester tester) async {
+      Completer<InAppWebViewController> controllerCompleter =
+      Completer<InAppWebViewController>();
+      Completer<void> pageStarted = Completer<void>();
+      Completer<void> pageLoaded = Completer<void>();
+
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: 'data:text/html;charset=utf-8;base64,$audioTestBase64',
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+                crossPlatform: InAppWebViewOptions(
+                    javaScriptEnabled: true,
+                    mediaPlaybackRequiresUserGesture: false
+                )
+            ),
+            onLoadStart: (controller, url) {
+              pageStarted.complete();
+            },
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+          ),
+        ),
+      );
+      InAppWebViewController controller = await controllerCompleter.future;
+      await pageStarted.future;
+      await pageLoaded.future;
+
+      bool isPaused = await controller.evaluateJavascript(source: 'isPaused();');
+      expect(isPaused, false);
+
+      controllerCompleter = Completer<InAppWebViewController>();
+      pageStarted = Completer<void>();
+      pageLoaded = Completer<void>();
+
+      // We change the key to re-create a new webview as we change the mediaPlaybackRequiresUserGesture
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: 'data:text/html;charset=utf-8;base64,$audioTestBase64',
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+                crossPlatform: InAppWebViewOptions(
+                    javaScriptEnabled: true,
+                    mediaPlaybackRequiresUserGesture: true
+                ),
+            ),
+            onLoadStart: (controller, url) {
+              pageStarted.complete();
+            },
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+          ),
+        ),
+      );
+
+      controller = await controllerCompleter.future;
+      await pageStarted.future;
+      await pageLoaded.future;
+
+      isPaused = await controller.evaluateJavascript(source: 'isPaused();');
+      expect(isPaused, true);
+    }/*, skip: true https://github.com/flutter/flutter/issues/72572 */);
+  });
+
+  testWidgets('getTitle', (WidgetTester tester) async {
+    final String getTitleTest = '''
+        <!DOCTYPE html><html>
+        <head><title>Some title</title>
+        </head>
+        <body>
+        </body>
+        </html>
+      ''';
+    final String getTitleTestBase64 =
+    base64Encode(const Utf8Encoder().convert(getTitleTest));
+    final Completer<void> pageStarted = Completer<void>();
+    final Completer<void> pageLoaded = Completer<void>();
+    final Completer controllerCompleter =
+    Completer<InAppWebViewController>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          initialUrl: 'data:text/html;charset=utf-8;base64,$getTitleTestBase64',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onLoadStart: (controller, url) {
+            pageStarted.complete();
+          },
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageStarted.future;
+    await pageLoaded.future;
+
+    final String title = await controller.getTitle();
+    expect(title, 'Some title');
+  });
+
+  group('Programmatic Scroll', () {
+    testWidgets('setAndGetScrollPosition', (WidgetTester tester) async {
+      final String scrollTestPage = '''
+        <!DOCTYPE html>
+        <html>
+          <head>
+            <style>
+              body {
+                height: 100%;
+                width: 100%;
+              }
+              #container{
+                width:5000px;
+                height:5000px;
+            }
+            </style>
+          </head>
+          <body>
+            <div id="container"/>
+          </body>
+        </html>
+      ''';
+
+      final String scrollTestPageBase64 =
+      base64Encode(const Utf8Encoder().convert(scrollTestPage));
+
+      final Completer<void> pageLoaded = Completer<void>();
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            initialUrl:
+            'data:text/html;charset=utf-8;base64,$scrollTestPageBase64',
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+          ),
+        ),
+      );
+
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await pageLoaded.future;
+
+      await tester.pumpAndSettle(Duration(seconds: 3));
+
+      // Check scrollTo()
+      const int X_SCROLL = 123;
+      const int Y_SCROLL = 321;
+
+      await controller.scrollTo(x: X_SCROLL, y: Y_SCROLL);
+      await tester.pumpAndSettle(Duration(seconds: 1));
+      int scrollPosX = await controller.getScrollX();
+      int scrollPosY = await controller.getScrollY();
+      expect(scrollPosX, X_SCROLL);
+      expect(scrollPosY, Y_SCROLL);
+
+      // Check scrollBy() (on top of scrollTo())
+      await controller.scrollBy(x: X_SCROLL, y: Y_SCROLL);
+      await tester.pumpAndSettle(Duration(seconds: 1));
+      scrollPosX = await controller.getScrollX();
+      scrollPosY = await controller.getScrollY();
+      expect(scrollPosX, X_SCROLL * 2);
+      expect(scrollPosY, Y_SCROLL * 2);
+    });
+  });
+
+  group('Android Hybrid Composition', () {
+    testWidgets('setAndGetScrollPosition', (WidgetTester tester) async {
+      final String scrollTestPage = '''
+        <!DOCTYPE html>
+        <html>
+          <head>
+            <style>
+              body {
+                height: 100%;
+                width: 100%;
+              }
+              #container{
+                width:5000px;
+                height:5000px;
+            }
+            </style>
+          </head>
+          <body>
+            <div id="container"/>
+          </body>
+        </html>
+      ''';
+
+      final String scrollTestPageBase64 =
+      base64Encode(const Utf8Encoder().convert(scrollTestPage));
+
+      final Completer<void> pageLoaded = Completer<void>();
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            initialUrl:
+            'data:text/html;charset=utf-8;base64,$scrollTestPageBase64',
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              android: AndroidInAppWebViewOptions(
+                useHybridComposition: true
+              )
+            ),
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+          ),
+        ),
+      );
+
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await pageLoaded.future;
+
+      await tester.pumpAndSettle(Duration(seconds: 3));
+
+      // Check scrollTo()
+      const int X_SCROLL = 123;
+      const int Y_SCROLL = 321;
+
+      await controller.scrollTo(x: X_SCROLL, y: Y_SCROLL);
+      await tester.pumpAndSettle(Duration(seconds: 1));
+      int scrollPosX = await controller.getScrollX();
+      int scrollPosY = await controller.getScrollY();
+      expect(scrollPosX, X_SCROLL);
+      expect(scrollPosY, Y_SCROLL);
+
+      // Check scrollBy() (on top of scrollTo())
+      await controller.scrollBy(x: X_SCROLL, y: Y_SCROLL);
+      await tester.pumpAndSettle(Duration(seconds: 1));
+      scrollPosX = await controller.getScrollX();
+      scrollPosY = await controller.getScrollY();
+      expect(scrollPosX, X_SCROLL * 2);
+      expect(scrollPosY, Y_SCROLL * 2);
+    });
+  }, skip: !Platform.isAndroid);
+
+  group('shouldOverrideUrlLoading', () {
+    final String page = '''<!DOCTYPE html><head></head><body><a id="link" href="https://github.com/pichillilorenzo/flutter_inappwebview">flutter_inappwebview</a></body></html>''';
+    final String pageEncoded = 'data:text/html;charset=utf-8;base64,' +
+        base64Encode(const Utf8Encoder().convert(page));
+
+    testWidgets('can allow requests', (WidgetTester tester) async {
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+      final StreamController<String> pageLoads = StreamController<String>.broadcast();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: pageEncoded,
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                useShouldOverrideUrlLoading: true
+              ),
+            ),
+            shouldOverrideUrlLoading: (controller, shouldOverrideUrlLoadingRequest) async {
+              return (shouldOverrideUrlLoadingRequest.url.contains('youtube.com'))
+                  ? ShouldOverrideUrlLoadingAction.CANCEL
+                  : ShouldOverrideUrlLoadingAction.ALLOW;
+            },
+            onLoadStop: (controller, url) {
+              pageLoads.add(url);
+            },
+          ),
+        ),
+      );
+
+      await pageLoads.stream.first; // Wait for initial page load.
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await controller
+          .evaluateJavascript(source: 'location.href = "https://www.google.com/"');
+
+      await pageLoads.stream.first; // Wait for the next page load.
+      final String currentUrl = await controller.getUrl();
+      expect(currentUrl, 'https://www.google.com/');
+    });
+
+    testWidgets('allow requests on iOS only if iosWKNavigationType == IOSWKNavigationType.LINK_ACTIVATED', (WidgetTester tester) async {
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+      final StreamController<String> pageLoads = StreamController<String>.broadcast();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: pageEncoded,
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  useShouldOverrideUrlLoading: true
+              ),
+            ),
+            shouldOverrideUrlLoading: (controller, shouldOverrideUrlLoadingRequest) async {
+              return (shouldOverrideUrlLoadingRequest.iosWKNavigationType == IOSWKNavigationType.LINK_ACTIVATED)
+                  ? ShouldOverrideUrlLoadingAction.ALLOW
+                  : ShouldOverrideUrlLoadingAction.CANCEL;
+            },
+            onLoadStop: (controller, url) {
+              pageLoads.add(url);
+            },
+          ),
+        ),
+      );
+
+      await pageLoads.stream.first; // Wait for initial page load.
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await controller.evaluateJavascript(source: 'location.href = "https://www.google.com/"');
+
+      // There should never be any second page load, since our new URL is
+      // blocked. Still wait for a potential page change for some time in order
+      // to give the test a chance to fail.
+      await pageLoads.stream.first
+          .timeout(const Duration(milliseconds: 500), onTimeout: () => null);
+      String currentUrl = await controller.getUrl();
+      expect(currentUrl, isNot('https://www.google.com/'));
+
+      await controller.evaluateJavascript(source: 'document.querySelector("#link").click();');
+      await pageLoads.stream.first; // Wait for the next page load.
+      currentUrl = await controller.getUrl();
+      expect(currentUrl, 'https://github.com/pichillilorenzo/flutter_inappwebview');
+    }, skip: !Platform.isIOS);
+
+    testWidgets('can block requests', (WidgetTester tester) async {
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+      final StreamController<String> pageLoads =
+      StreamController<String>.broadcast();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: pageEncoded,
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  useShouldOverrideUrlLoading: true
+              ),
+            ),
+            shouldOverrideUrlLoading: (controller, shouldOverrideUrlLoadingRequest) async {
+              return (shouldOverrideUrlLoadingRequest.url.contains('youtube.com'))
+                  ? ShouldOverrideUrlLoadingAction.CANCEL
+                  : ShouldOverrideUrlLoadingAction.ALLOW;
+            },
+            onLoadStop: (controller, url) {
+              pageLoads.add(url);
+            },
+          ),
+        ),
+      );
+
+      await pageLoads.stream.first; // Wait for initial page load.
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await controller
+          .evaluateJavascript(source: 'location.href = "https://www.youtube.com/"');
+
+      // There should never be any second page load, since our new URL is
+      // blocked. Still wait for a potential page change for some time in order
+      // to give the test a chance to fail.
+      await pageLoads.stream.first
+          .timeout(const Duration(milliseconds: 500), onTimeout: () => null);
+      final String currentUrl = await controller.getUrl();
+      expect(currentUrl, isNot(contains('youtube.com')));
+    });
+
+    testWidgets('supports asynchronous decisions', (WidgetTester tester) async {
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+      final StreamController<String> pageLoads =
+      StreamController<String>.broadcast();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            initialUrl: pageEncoded,
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  useShouldOverrideUrlLoading: true
+              ),
+            ),
+            shouldOverrideUrlLoading: (controller, shouldOverrideUrlLoadingRequest) async {
+              var action = ShouldOverrideUrlLoadingAction.CANCEL;
+              action = await Future<ShouldOverrideUrlLoadingAction>.delayed(
+                  const Duration(milliseconds: 10),
+                      () => ShouldOverrideUrlLoadingAction.ALLOW);
+              return action;
+            },
+            onLoadStop: (controller, url) {
+              pageLoads.add(url);
+            },
+          ),
+        ),
+      );
+
+      await pageLoads.stream.first; // Wait for initial page load.
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await controller
+          .evaluateJavascript(source: 'location.href = "https://www.google.com"');
+
+      await pageLoads.stream.first; // Wait for second page to load.
+      final String currentUrl = await controller.getUrl();
+      expect(currentUrl, 'https://www.google.com/');
+    });
+  });
+
+  testWidgets('onLoadError', (WidgetTester tester) async {
+    final Completer<String> errorUrlCompleter = Completer<String>();
+    final Completer<int> errorCodeCompleter = Completer<int>();
+    final Completer<String> errorMessageCompleter = Completer<String>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://www.notawebsite..com',
+          onLoadError: (controller, url, code, message) {
+            errorUrlCompleter.complete(url);
+            errorCodeCompleter.complete(code);
+            errorMessageCompleter.complete(message);
+          },
+        ),
+      ),
+    );
+
+    final String url = await errorUrlCompleter.future;
+    final int code = await errorCodeCompleter.future;
+    final String message = await errorMessageCompleter.future;
+
+    if (Platform.isAndroid) {
+      expect(code, -2);
+    } else if (Platform.isIOS) {
+      expect(code, -1003);
+    }
+    expect(url, 'https://www.notawebsite..com/');
+  });
+
+  testWidgets('onLoadError is not called with valid url',
+          (WidgetTester tester) async {
+        final Completer<String> errorUrlCompleter = Completer<String>();
+        final Completer<int> errorCodeCompleter = Completer<int>();
+        final Completer<String> errorMessageCompleter = Completer<String>();
+
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              initialUrl:
+              'data:text/html;charset=utf-8;base64,PCFET0NUWVBFIGh0bWw+',
+              onLoadError: (controller, url, code, message) {
+                errorUrlCompleter.complete(url);
+                errorCodeCompleter.complete(code);
+                errorMessageCompleter.complete(message);
+              },
+            ),
+          ),
+        );
+
+        expect(errorUrlCompleter.future, doesNotComplete);
+        expect(errorCodeCompleter.future, doesNotComplete);
+        expect(errorMessageCompleter.future, doesNotComplete);
+      });
+
+  testWidgets('launches with allowsBackForwardNavigationGestures true on iOS',
+          (WidgetTester tester) async {
+        final Completer controllerCompleter =
+        Completer<InAppWebViewController>();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: SizedBox(
+              width: 400,
+              height: 300,
+              child: InAppWebView(
+                key: GlobalKey(),
+                initialUrl: 'https://flutter.dev/',
+                initialOptions: InAppWebViewGroupOptions(
+                  ios: IOSInAppWebViewOptions(
+                    allowsBackForwardNavigationGestures: true
+                  )
+                ),
+                onWebViewCreated: (controller) {
+                  controllerCompleter.complete(controller);
+                },
+              ),
+            ),
+          ),
+        );
+        final InAppWebViewController controller = await controllerCompleter.future;
+        final String currentUrl = await controller.getUrl();
+        expect(currentUrl, contains('flutter.dev'));
+      });
+
+  testWidgets('target _blank opens in same window',
+          (WidgetTester tester) async {
+        final Completer controllerCompleter =
+        Completer<InAppWebViewController>();
+        final StreamController<String> pageLoads = StreamController<String>.broadcast();
+        await tester.pumpWidget(
+          Directionality(
+            textDirection: TextDirection.ltr,
+            child: InAppWebView(
+              key: GlobalKey(),
+              onWebViewCreated: (controller) {
+                controllerCompleter.complete(controller);
+              },
+              initialOptions: InAppWebViewGroupOptions(
+                crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  javaScriptCanOpenWindowsAutomatically: true
+                ),
+              ),
+              onLoadStop: (controller, url) {
+                pageLoads.add(url);
+              },
+            ),
+          ),
+        );
+        await pageLoads.stream.first;
+        final InAppWebViewController controller = await controllerCompleter.future;
+
+        await controller.evaluateJavascript(source: 'window.open("about:blank", "_blank")');
+        await pageLoads.stream.first;
+        final String currentUrl = await controller.getUrl();
+        expect(currentUrl, 'about:blank');
+      });
+
+  testWidgets(
+    'can open new window and go back',
+        (WidgetTester tester) async {
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+      final StreamController<String> pageLoads = StreamController<String>.broadcast();
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  javaScriptCanOpenWindowsAutomatically: true
+              ),
+            ),
+            onLoadStop: (controller, url) {
+              pageLoads.add(url);
+            },
+            initialUrl: 'https://flutter.dev',
+          ),
+        ),
+      );
+      await pageLoads.stream.first;
+      final InAppWebViewController controller = await controllerCompleter.future;
+
+      await controller
+          .evaluateJavascript(source: 'window.open("https://www.google.com")');
+      await pageLoads.stream.first;
+      expect(await controller.getUrl(), contains('google.com'));
+
+      await controller.goBack();
+      await pageLoads.stream.first;
+      expect(await controller.getUrl(), contains('flutter.dev'));
+    },
+    skip: !Platform.isAndroid,
+  );
+
+  testWidgets(
+    'javascript does not run in parent window',
+        (WidgetTester tester) async {
+      final String iframe = '''
+        <!DOCTYPE html>
+        <script>
+          window.onload = () => {
+            window.open(`javascript:
+              var elem = document.createElement("p");
+              elem.innerHTML = "<b>Executed JS in parent origin: " + window.location.origin + "</b>";
+              document.body.append(elem);
+            `);
+          };
+        </script>
+      ''';
+      final String iframeTestBase64 =
+      base64Encode(const Utf8Encoder().convert(iframe));
+
+      final String openWindowTest = '''
+        <!DOCTYPE html>
+        <html>
+        <head>
+          <title>XSS test</title>
+        </head>
+        <body>
+          <iframe
+            onload="window.iframeLoaded = true;"
+            src="data:text/html;charset=utf-8;base64,$iframeTestBase64"></iframe>
+        </body>
+        </html>
+      ''';
+      final String openWindowTestBase64 =
+      base64Encode(const Utf8Encoder().convert(openWindowTest));
+      final Completer controllerCompleter =
+      Completer<InAppWebViewController>();
+      final Completer<void> pageLoadCompleter = Completer<void>();
+
+      await tester.pumpWidget(
+        Directionality(
+          textDirection: TextDirection.ltr,
+          child: InAppWebView(
+            key: GlobalKey(),
+            onWebViewCreated: (controller) {
+              controllerCompleter.complete(controller);
+            },
+            initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  javaScriptEnabled: true,
+                  javaScriptCanOpenWindowsAutomatically: true
+              ),
+            ),
+            initialUrl:
+            'data:text/html;charset=utf-8;base64,$openWindowTestBase64',
+            onLoadStop: (controller, url) {
+              pageLoadCompleter.complete();
+            },
+          ),
+        ),
+      );
+
+      final InAppWebViewController controller = await controllerCompleter.future;
+      await pageLoadCompleter.future;
+
+      await expectLater(controller.evaluateJavascript(source: 'iframeLoaded'), completion(true));
+      await expectLater(
+        controller.evaluateJavascript(
+            source: 'document.querySelector("p") && document.querySelector("p").textContent'),
+        completion(null),
+      );
+    },
+    skip: !Platform.isAndroid,
+  );
+
+  testWidgets('intercept ajax request', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer shouldInterceptAjaxPostRequestCompleter = Completer<void>();
+    final Completer<Map<String, dynamic>> onAjaxReadyStateChangeCompleter = Completer<Map<String, dynamic>>();
+    final Completer<Map<String, dynamic>> onAjaxProgressCompleter = Completer<Map<String, dynamic>>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewAjaxTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewAjaxTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            var xhttp = new XMLHttpRequest();
+            xhttp.open("POST", "http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post");
+            xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
+            xhttp.send("firstname=Foo&lastname=Bar");
+
+            var xhttp2 = new XMLHttpRequest();
+            xhttp2.open("GET", "http://${environment["NODE_SERVER_IP"]}:8082/test-download-file");
+            xhttp2.send();
+          });
+        </script>
+    </body>
+</html>
+                    """),
+          initialHeaders: {},
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+                useShouldInterceptAjaxRequest: true,
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          shouldInterceptAjaxRequest: (controller, ajaxRequest) async {
+            if (ajaxRequest.url.endsWith("/test-ajax-post")) {
+              ajaxRequest.responseType = 'json';
+              ajaxRequest.data = "firstname=Foo2&lastname=Bar2";
+              shouldInterceptAjaxPostRequestCompleter.complete(controller);
+            }
+            return ajaxRequest;
+          },
+          onAjaxReadyStateChange: (controller, ajaxRequest) async {
+            if (ajaxRequest.readyState == AjaxRequestReadyState.DONE && ajaxRequest.status == 200 && ajaxRequest.url.endsWith("/test-ajax-post")) {
+              Map<String, dynamic> res = ajaxRequest.response;
+              onAjaxReadyStateChangeCompleter.complete(res);
+            }
+            return AjaxRequestAction.PROCEED;
+          },
+          onAjaxProgress: (controller, ajaxRequest) async {
+            if (ajaxRequest.event.type == AjaxRequestEventType.LOAD && ajaxRequest.url.endsWith("/test-ajax-post")) {
+              Map<String, Object> res = ajaxRequest.response;
+              onAjaxProgressCompleter.complete(res);
+            }
+            return AjaxRequestAction.PROCEED;
+          },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await shouldInterceptAjaxPostRequestCompleter.future;
+    final Map<String, dynamic> onAjaxReadyStateChangeValue = await onAjaxReadyStateChangeCompleter.future;
+    final Map<String, dynamic> onAjaxProgressValue = await onAjaxProgressCompleter.future;
+
+    expect(mapEquals(onAjaxReadyStateChangeValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}), true);
+    expect(mapEquals(onAjaxProgressValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}), true);
+  });
+
+  testWidgets('Content Blocker', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  clearCache: true,
+                  contentBlockers: [
+                    ContentBlocker(
+                        trigger: ContentBlockerTrigger(
+                            urlFilter: ".*",
+                            resourceType: [
+                              ContentBlockerTriggerResourceType.IMAGE,
+                              ContentBlockerTriggerResourceType.STYLE_SHEET
+                            ],
+                            ifTopUrl: [
+                              "https://flutter.dev/"
+                            ]),
+                        action: ContentBlockerAction(
+                            type: ContentBlockerActionType.BLOCK))
+                  ]
+              )
+          ),
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await expectLater(pageLoaded.future, completes);
+  });
+
+  testWidgets('Cookie Manager', (WidgetTester tester) async {
+    CookieManager cookieManager = CookieManager.instance();
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<String> pageLoaded = Completer<String>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  clearCache: true,
+              )
+          ),
+          onLoadStop: (controller, url) {
+            pageLoaded.complete(url);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    final String url = await pageLoaded.future;
+
+    await cookieManager.setCookie(url: url, name: "myCookie", value: "myValue");
+    List<Cookie> cookies = await cookieManager.getCookies(url: url);
+    expect(cookies, isNotEmpty);
+
+    Cookie cookie = await cookieManager.getCookie(url: url, name: "myCookie");
+    expect(cookie.value.toString(), "myValue");
+
+    await cookieManager.deleteCookie(url: url, name: "myCookie");
+    cookie = await cookieManager.getCookie(url: url, name: "myCookie");
+    expect(cookie, isNull);
+
+    await cookieManager.deleteCookies(url: url);
+    cookies = await cookieManager.getCookies(url: url);
+    expect(cookies, isEmpty);
+  });
+
+  testWidgets('intercept fetch request', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<String> fetchGetCompleter = Completer<String>();
+    final Completer<Map<String, dynamic>> fetchPostCompleter = Completer<Map<String, dynamic>>();
+    final Completer<void> shouldInterceptFetchPostRequestCompleter = Completer<void>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewFetchTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewFetchTest</h1>
+        <script>
+          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
+            fetch(new Request("http://${environment["NODE_SERVER_IP"]}:8082/test-download-file")).then(function(response) {
+                window.flutter_inappwebview.callHandler('fetchGet', response.status);
+            }).catch(function(error) {
+                window.flutter_inappwebview.callHandler('fetchGet', "ERROR: " + error);
+            });
+
+            fetch("http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post", {
+                method: 'POST',
+                body: JSON.stringify({
+                    firstname: 'Foo',
+                    lastname: 'Bar'
+                }),
+                headers: {
+                  'Content-Type': 'application/json'
+                }
+            }).then(function(response) {
+                response.json().then(function(value) {
+                  window.flutter_inappwebview.callHandler('fetchPost', value);
+                }).catch(function(error) {
+                    window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+                });
+            }).catch(function(error) {
+                window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
+            });
+          });
+        </script>
+    </body>
+</html>
+                    """),
+          initialHeaders: {},
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+                useShouldInterceptFetchRequest: true,
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+
+            controller.addJavaScriptHandler(handlerName: "fetchGet", callback: (args) {
+              fetchGetCompleter.complete(args[0].toString());
+            });
+
+            controller.addJavaScriptHandler(handlerName: "fetchPost", callback: (args) {
+              fetchPostCompleter.complete(args[0] as Map<String, dynamic>);
+            });
+          },
+          shouldInterceptFetchRequest: (controller, fetchRequest) async {
+            if (fetchRequest.url.endsWith("/test-ajax-post")) {
+              fetchRequest.body = utf8.encode("""{
+                "firstname": "Foo2",
+                "lastname": "Bar2"
+              }
+              """);
+              shouldInterceptFetchPostRequestCompleter.complete();
+            }
+            return fetchRequest;
+          },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+
+    var fetchGetCompleterValue = await fetchGetCompleter.future;
+    expect(fetchGetCompleterValue, '200');
+
+    await shouldInterceptFetchPostRequestCompleter.future;
+    var fetchPostCompleterValue = await fetchPostCompleter.future;
+
+    expect(mapEquals(fetchPostCompleterValue, {'firstname': 'Foo2', 'lastname': 'Bar2'}), true);
+  });
+
+  testWidgets('Http Auth Credential Database', (WidgetTester tester) async {
+    HttpAuthCredentialDatabase httpAuthCredentialDatabase = HttpAuthCredentialDatabase.instance();
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+
+    httpAuthCredentialDatabase.setHttpAuthCredential(
+        protectionSpace: ProtectionSpace(host: environment["NODE_SERVER_IP"], protocol: "http", realm: "Node", port: 8081),
+        credential: HttpAuthCredential(username: "USERNAME", password: "PASSWORD")
+    );
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: "http://${environment["NODE_SERVER_IP"]}:8081/",
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+              )
+          ),
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+          onReceivedHttpAuthRequest: (controller, challenge) async {
+            return new HttpAuthResponse(action: HttpAuthResponseAction.USE_SAVED_HTTP_AUTH_CREDENTIALS);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    final String h1Content = await controller.evaluateJavascript(source: "document.body.querySelector('h1').textContent");
+    expect(h1Content, "Authorized");
+
+    var credentials = await httpAuthCredentialDatabase.getHttpAuthCredentials(protectionSpace:
+      ProtectionSpace(host: environment["NODE_SERVER_IP"], protocol: "http", realm: "Node", port: 8081)
+    );
+    expect(credentials.length, 1);
+
+    await httpAuthCredentialDatabase.clearAllAuthCredentials();
+    credentials = await httpAuthCredentialDatabase.getHttpAuthCredentials(protectionSpace:
+      ProtectionSpace(host: environment["NODE_SERVER_IP"], protocol: "http", realm: "Node", port: 8081)
+    );
+    expect(credentials, isEmpty);
+  });
+
+  testWidgets('onReceivedHttpAuthRequest', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: "http://${environment["NODE_SERVER_IP"]}:8081/",
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+              )
+          ),
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+          onReceivedHttpAuthRequest: (controller, challenge) async {
+            return new HttpAuthResponse(
+                username: "USERNAME",
+                password: "PASSWORD",
+                action: HttpAuthResponseAction.PROCEED,
+                permanentPersistence: true);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    final String h1Content = await controller.evaluateJavascript(source: "document.body.querySelector('h1').textContent");
+    expect(h1Content, "Authorized");
+  });
+
+  testWidgets('onConsoleMessage', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<ConsoleMessage> onConsoleMessageCompleter = Completer<ConsoleMessage>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_on_console_message_test.html",
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onConsoleMessage: (controller, consoleMessage) {
+            onConsoleMessageCompleter.complete(consoleMessage);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    final ConsoleMessage consoleMessage = await onConsoleMessageCompleter.future;
+    expect(consoleMessage.message, 'message');
+    expect(consoleMessage.messageLevel, ConsoleMessageLevel.LOG);
+  });
+
+  testWidgets('onCreateWindow', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> newWindowOpenedCompleter = Completer<void>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_on_create_window_test.html",
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+                javaScriptCanOpenWindowsAutomatically: true,
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onLoadStop: (controller, url) {
+            if (url == "https://flutter.dev/") {
+              newWindowOpenedCompleter.complete();
+            }
+          },
+          onCreateWindow: (controller, createWindowRequest) async {
+            controller.loadUrl(url: createWindowRequest.url);
+            return null;
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await expectLater(newWindowOpenedCompleter.future, completes);
+  });
+
+  testWidgets('onDownloadStart', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<String> onDownloadStartCompleter = Completer<String>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialData: InAppWebViewInitialData(data: """
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8">
+        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+        <meta http-equiv="X-UA-Compatible" content="ie=edge">
+        <title>InAppWebViewOnDownloadStartTest</title>
+    </head>
+    <body>
+        <h1>InAppWebViewOnDownloadStartTest</h1>
+        <a id="download-file" href="http://${environment["NODE_SERVER_IP"]}:8082/test-download-file">download file</a>
+        <script>
+            window.addEventListener("flutterInAppWebViewPlatformReady", function(event) {
+                document.querySelector("#download-file").click();
+            });
+        </script>
+    </body>
+</html>
+          """),
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+                useOnDownloadStart: true
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onDownloadStart: (controller, url) {
+            onDownloadStartCompleter.complete(url);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    final String url = await onDownloadStartCompleter.future;
+    expect(url, "http://${environment["NODE_SERVER_IP"]}:8082/test-download-file");
+  });
+
+  testWidgets('onFindResultReceived', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<int> numberOfMatchesCompleter = Completer<int>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_initial_file_test.html",
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onLoadStop: (controller, url) {
+            controller.findAllAsync(find: "InAppWebViewInitialFileTest");
+          },
+          onFindResultReceived: (controller, int activeMatchOrdinal, int numberOfMatches, bool isDoneCounting) async {
+            if (isDoneCounting && !numberOfMatchesCompleter.isCompleted) {
+              numberOfMatchesCompleter.complete(numberOfMatches);
+            }
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    final int numberOfMatches = await numberOfMatchesCompleter.future;
+    expect(numberOfMatches, 2);
+  });
+
+  testWidgets('javascript dialogs', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+    final Completer<JsAlertRequest> alertCompleter = Completer<JsAlertRequest>();
+    final Completer<bool> confirmCompleter = Completer<bool>();
+    final Completer<String> promptCompleter = Completer<String>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_on_js_dialog_test.html",
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                clearCache: true,
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+
+            controller.addJavaScriptHandler(handlerName: 'confirm', callback: (args) {
+              confirmCompleter.complete(args[0] as bool);
+            });
+
+            controller.addJavaScriptHandler(handlerName: 'prompt', callback: (args) {
+              promptCompleter.complete(args[0] as String);
+            });
+          },
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+          onJsAlert:
+              (controller, jsAlertRequest) async {
+            JsAlertResponseAction action = JsAlertResponseAction.CONFIRM;
+            alertCompleter.complete(jsAlertRequest);
+            return JsAlertResponse(
+                handledByClient: true, action: action);
+          },
+          onJsConfirm:
+              (controller, jsConfirmRequest) async {
+            JsConfirmResponseAction action = JsConfirmResponseAction.CONFIRM;
+            return JsConfirmResponse(
+                handledByClient: true, action: action);
+          },
+          onJsPrompt: (controller, jsPromptRequest) async {
+            JsPromptResponseAction action = JsPromptResponseAction.CONFIRM;
+            return JsPromptResponse(
+                handledByClient: true,
+                action: action,
+                value: 'new value');
+          },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    final JsAlertRequest jsAlertRequest = await alertCompleter.future;
+    expect(jsAlertRequest.message, 'alert message');
+
+    final bool onJsConfirmValue = await confirmCompleter.future;
+    expect(onJsConfirmValue, true);
+
+    final String onJsPromptValue = await promptCompleter.future;
+    expect(onJsPromptValue, 'new value');
+  });
+
+  testWidgets('onLoadHttpError', (WidgetTester tester) async {
+    final Completer<String> errorUrlCompleter = Completer<String>();
+    final Completer<int> statusCodeCompleter = Completer<int>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://google.com/404',
+          onLoadHttpError: (controller, url, statusCode, description) async {
+            errorUrlCompleter.complete(url);
+            statusCodeCompleter.complete(statusCode);
+          },
+        ),
+      ),
+    );
+
+    final String url = await errorUrlCompleter.future;
+    final int code = await statusCodeCompleter.future;
+
+    expect(url, 'https://google.com/404');
+    expect(code, 404);
+  });
+
+  testWidgets('onLoadResourceCustomScheme', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> imageLoaded = Completer<void>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_on_load_resource_custom_scheme_test.html",
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  clearCache: true,
+                  resourceCustomSchemes: ["my-special-custom-scheme"]
+              )
+          ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+
+            controller.addJavaScriptHandler(handlerName: "imageLoaded", callback: (args) {
+              imageLoaded.complete();
+            });
+          },
+          onLoadResourceCustomScheme: (controller, scheme, url) async {
+            if (scheme == "my-special-custom-scheme") {
+              var bytes = await rootBundle.load("test_assets/" + url.replaceFirst("my-special-custom-scheme://", "", 0));
+              var response = CustomSchemeResponse(data: bytes.buffer.asUint8List(), contentType: "image/svg+xml", contentEnconding: "utf-8");
+              return response;
+            }
+            return null;
+          },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await expectLater(imageLoaded.future, completes);
+  });
+
+  testWidgets('onLoadResource', (WidgetTester tester) async {
+    List<String> resourceList = [
+      "https://getbootstrap.com/docs/4.3/dist/css/bootstrap.min.css",
+      "https://code.jquery.com/jquery-3.3.1.min.js",
+      "https://via.placeholder.com/100x50"
+    ];
+    List<String> resourceLoaded = [];
+
+    final Completer<void> loadedResourceCompleter = Completer<void>();
+    final Completer<void> pageLoaded = Completer<void>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialFile: "test_assets/in_app_webview_on_load_resource_test.html",
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  clearCache: true,
+                  useOnLoadResource: true
+              )
+          ),
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+          onLoadResource: (controller, response) async {
+            resourceLoaded.add(response.url);
+            if (resourceLoaded.length == resourceList.length) {
+              loadedResourceCompleter.complete();
+            }
+          }
+        ),
+      ),
+    );
+
+    await pageLoaded.future;
+    await loadedResourceCompleter.future;
+
+    expect(resourceLoaded, unorderedEquals(resourceList));
+  });
+
+  testWidgets('onUpdateVisitedHistory', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> firstPushCompleter = Completer<void>();
+    final Completer<void> secondPushCompleter = Completer<void>();
+    final Completer<void> pageLoaded = Completer<void>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+            key: GlobalKey(),
+          initialUrl: "https://flutter.dev/",
+            initialOptions: InAppWebViewGroupOptions(
+                crossPlatform: InAppWebViewOptions(
+                    clearCache: true
+                )
+            ),
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+            onLoadStop: (controller, url) {
+              pageLoaded.complete();
+            },
+            onUpdateVisitedHistory: (controller, url, androidIsReload) async {
+              if (url.endsWith("second-push")) {
+                secondPushCompleter.complete();
+              } else if (url.endsWith("first-push")) {
+                firstPushCompleter.complete();
+              }
+            },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    await controller.evaluateJavascript(source: """
+var state = {}
+var title = ''
+var url = 'first-push';
+history.pushState(state, title, url);
+
+setTimeout(function() {
+    var url = 'second-push';
+    history.pushState(state, title, url);
+}, 500);
+""");
+
+    await firstPushCompleter.future;
+    expect(await controller.getUrl(), 'https://flutter.dev/first-push');
+
+    await secondPushCompleter.future;
+    expect(await controller.getUrl(), 'https://flutter.dev/second-push');
+  });
+
+  testWidgets('onProgressChanged', (WidgetTester tester) async {
+    final Completer<void> onProgressChangedCompleter = Completer<void>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          initialOptions: InAppWebViewGroupOptions(
+              crossPlatform: InAppWebViewOptions(
+                  clearCache: true,
+              )
+          ),
+          onProgressChanged: (controller, progress) {
+            if (progress == 100) {
+              onProgressChangedCompleter.complete();
+            }
+          },
+        ),
+      ),
+    );
+    await expectLater(onProgressChangedCompleter.future, completes);
+  });
+
+  testWidgets('androidOnSafeBrowsingHit', (WidgetTester tester) async {
+    final Completer<String> pageLoaded = Completer<String>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'chrome://safe-browsing/match?type=malware',
+          initialOptions: InAppWebViewGroupOptions(
+            crossPlatform: InAppWebViewOptions(
+              // if I set javaScriptEnabled to true, it will crash!
+                javaScriptEnabled: false,
+                clearCache: true,
+            ),
+            android: AndroidInAppWebViewOptions(
+              safeBrowsingEnabled: true,
+            ),
+          ),
+          onWebViewCreated: (controller) {
+            controller.android.startSafeBrowsing();
+          },
+          onLoadStop: (controller, url) {
+            pageLoaded.complete(url);
+          },
+          androidOnSafeBrowsingHit: (controller, url, threatType) async {
+            return SafeBrowsingResponse(report: true, action: SafeBrowsingResponseAction.PROCEED);
+          },
+        ),
+      ),
+    );
+
+    final String url = await pageLoaded.future;
+    expect(url, "chrome://safe-browsing/match?type=malware");
+  }, skip: !Platform.isAndroid);
+
+  testWidgets('onScrollChanged', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+    final Completer<void> onScrollChangedCompleter = Completer<void>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: 'https://flutter.dev/',
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+          onScrollChanged: (controller, x, y) {
+            if (x == 0 && y == 500) {
+              onScrollChangedCompleter.complete();
+            }
+          },
+        ),
+      ),
+    );
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    controller.scrollTo(x: 0, y: 500);
+    await tester.pumpAndSettle(Duration(seconds: 1));
+
+    await expectLater(onScrollChangedCompleter.future, completes);
+  });
+
+  testWidgets('SSL request', (WidgetTester tester) async {
+    final Completer controllerCompleter = Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          initialUrl: "https://${environment["NODE_SERVER_IP"]}:4433/",
+          onWebViewCreated: (controller) {
+            controllerCompleter.complete(controller);
+          },
+          onLoadStop: (controller, url) {
+            pageLoaded.complete();
+          },
+          onReceivedServerTrustAuthRequest: (controller, challenge) async {
+            return new ServerTrustAuthResponse(action: ServerTrustAuthResponseAction.PROCEED);
+          },
+          onReceivedClientCertRequest: (controller, challenge) async {
+            return new ClientCertResponse(
+                certificatePath: "test_assets/certificate.pfx",
+                certificatePassword: "",
+                androidKeyStoreType: "PKCS12",
+                action: ClientCertResponseAction.PROCEED);
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    final String h1Content = await controller.evaluateJavascript(source: "document.body.querySelector('h1').textContent");
+    expect(h1Content, "Authorized");
+  });
+}
diff --git a/example/ios/Flutter/Debug.xcconfig b/example/ios/Flutter/Debug.xcconfig
index 1fce94d3..8ad039b7 100755
--- a/example/ios/Flutter/Debug.xcconfig
+++ b/example/ios/Flutter/Debug.xcconfig
@@ -1,3 +1,4 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Generated.xcconfig"
 FLUTTER_BUILD_MODE=debug
\ No newline at end of file
diff --git a/example/ios/Flutter/Flutter.podspec b/example/ios/Flutter/Flutter.podspec
old mode 100755
new mode 100644
index 5ca30416..2c4421cf
--- a/example/ios/Flutter/Flutter.podspec
+++ b/example/ios/Flutter/Flutter.podspec
@@ -1,18 +1,18 @@
 #
 # NOTE: This podspec is NOT to be published. It is only used as a local source!
+#       This is a generated file; do not edit or check into version control.
 #
 
 Pod::Spec.new do |s|
   s.name             = 'Flutter'
   s.version          = '1.0.0'
   s.summary          = 'High-performance, high-fidelity mobile apps.'
-  s.description      = <<-DESC
-Flutter provides an easy and productive way to build and deploy high-performance mobile apps for Android and iOS.
-                       DESC
   s.homepage         = 'https://flutter.io'
   s.license          = { :type => 'MIT' }
   s.author           = { 'Flutter Dev Team' => 'flutter-dev@googlegroups.com' }
   s.source           = { :git => 'https://github.com/flutter/engine', :tag => s.version.to_s }
   s.ios.deployment_target = '8.0'
-  s.vendored_frameworks = 'Flutter.framework'
+  # Framework linking is handled by Flutter tooling, not CocoaPods.
+  # Add a placeholder to satisfy `s.dependency 'Flutter'` plugin podspecs.
+  s.vendored_frameworks = 'path/to/nothing'
 end
diff --git a/example/ios/Flutter/Release.xcconfig b/example/ios/Flutter/Release.xcconfig
index 399e9340..88c29144 100755
--- a/example/ios/Flutter/Release.xcconfig
+++ b/example/ios/Flutter/Release.xcconfig
@@ -1,2 +1,3 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Generated.xcconfig"
diff --git a/example/ios/Flutter/flutter_export_environment.sh b/example/ios/Flutter/flutter_export_environment.sh
index 0e6ac9c7..1d1cd30c 100755
--- a/example/ios/Flutter/flutter_export_environment.sh
+++ b/example/ios/Flutter/flutter_export_environment.sh
@@ -5,11 +5,10 @@ export "FLUTTER_APPLICATION_PATH=/Users/lorenzopichilli/Desktop/flutter_inappweb
 export "FLUTTER_TARGET=/Users/lorenzopichilli/Desktop/flutter_inappwebview/example/lib/main.dart"
 export "FLUTTER_BUILD_DIR=build"
 export "SYMROOT=${SOURCE_ROOT}/../build/ios"
-export "OTHER_LDFLAGS=$(inherited) -framework Flutter"
-export "FLUTTER_FRAMEWORK_DIR=/Users/lorenzopichilli/flutter/bin/cache/artifacts/engine/ios"
 export "FLUTTER_BUILD_NAME=1.0.0"
 export "FLUTTER_BUILD_NUMBER=1"
+export "DART_DEFINES=flutter.inspector.structuredErrors%3Dtrue,FLUTTER_WEB_AUTO_DETECT%3Dtrue"
 export "DART_OBFUSCATION=false"
 export "TRACK_WIDGET_CREATION=true"
 export "TREE_SHAKE_ICONS=false"
-export "PACKAGE_CONFIG=.packages"
+export "PACKAGE_CONFIG=/Users/lorenzopichilli/Desktop/flutter_inappwebview/example/.dart_tool/package_config.json"
diff --git a/example/ios/Runner.xcodeproj/project.pbxproj b/example/ios/Runner.xcodeproj/project.pbxproj
index 8610a573..db262e68 100644
--- a/example/ios/Runner.xcodeproj/project.pbxproj
+++ b/example/ios/Runner.xcodeproj/project.pbxproj
@@ -254,19 +254,17 @@
 			);
 			inputPaths = (
 				"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
-				"${PODS_ROOT}/../Flutter/Flutter.framework",
-				"${BUILT_PRODUCTS_DIR}/e2e/e2e.framework",
 				"${BUILT_PRODUCTS_DIR}/flutter_downloader/flutter_downloader.framework",
 				"${BUILT_PRODUCTS_DIR}/flutter_inappwebview/flutter_inappwebview.framework",
+				"${BUILT_PRODUCTS_DIR}/integration_test/integration_test.framework",
 				"${BUILT_PRODUCTS_DIR}/path_provider/path_provider.framework",
 				"${BUILT_PRODUCTS_DIR}/url_launcher/url_launcher.framework",
 			);
 			name = "[CP] Embed Pods Frameworks";
 			outputPaths = (
-				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/Flutter.framework",
-				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/e2e.framework",
 				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/flutter_downloader.framework",
 				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/flutter_inappwebview.framework",
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/integration_test.framework",
 				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/path_provider.framework",
 				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/url_launcher.framework",
 			);
@@ -451,7 +449,7 @@
 					"$(inherited)",
 					"$(PROJECT_DIR)/Flutter",
 				);
-				PRODUCT_BUNDLE_IDENTIFIER = com.pichillilorenzo.flutter_inappwebviewExample;
+				PRODUCT_BUNDLE_IDENTIFIER = "flutter-inappwebviewExample";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_OBJC_BRIDGING_HEADER = "Runner/Runner-Bridging-Header.h";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
diff --git a/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata b/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
index 1d526a16..919434a6 100755
--- a/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
+++ b/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
@@ -2,6 +2,6 @@
 <Workspace
    version = "1.0">
    <FileRef
-      location = "group:Runner.xcodeproj">
+      location = "self:">
    </FileRef>
 </Workspace>
diff --git a/example/ios/Runner/Info.plist b/example/ios/Runner/Info.plist
index a57480bf..f32f02ae 100755
--- a/example/ios/Runner/Info.plist
+++ b/example/ios/Runner/Info.plist
@@ -2,54 +2,52 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-	<key>NSLocationAlwaysUsageDescription</key>
-	<string>Need location</string>
-	<key>NSLocationWhenInUseUsageDescription</key>
-	<string>Need location</string>
-	<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
-	<string>Need location</string>
-	<key>CFBundleIdentifier</key>
-	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
-	<key>CFBundleName</key>
-	<string>flutter_inappwebview_example</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleVersion</key>
-	<string>$(FLUTTER_BUILD_NUMBER)</string>
-	<key>UIBackgroundModes</key>
-	<array>
-		<string>fetch</string>
-		<string>remote-notification</string>
-	</array>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
 	<key>CFBundleExecutable</key>
 	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>flutter_inappwebview_example</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(FLUTTER_BUILD_NAME)</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>$(FLUTTER_BUILD_NUMBER)</string>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
-	<key>UILaunchStoryboardName</key>
-	<string>LaunchScreen</string>
-	<key>UIMainStoryboardFile</key>
-	<string>Main</string>
 	<key>NSAppTransportSecurity</key>
 	<dict>
 		<key>NSAllowsLocalNetworking</key>
 		<true/>
 	</dict>
+	<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
+	<string>Need location</string>
+	<key>NSLocationAlwaysUsageDescription</key>
+	<string>Need location</string>
+	<key>NSLocationWhenInUseUsageDescription</key>
+	<string>Need location</string>
+	<key>UIBackgroundModes</key>
+	<array>
+		<string>fetch</string>
+		<string>remote-notification</string>
+	</array>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIMainStoryboardFile</key>
+	<string>Main</string>
 	<key>UISupportedInterfaceOrientations</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>
 		<string>UIInterfaceOrientationLandscapeLeft</string>
 		<string>UIInterfaceOrientationLandscapeRight</string>
 	</array>
-	<key>UIViewControllerBasedStatusBarAppearance</key>
-	<false/>
-	<key>io.flutter.embedded_views_preview</key>
-	<true/>
-	<key>CFBundleSignature</key>
-	<string>????</string>
-	<key>CFBundlePackageType</key>
-	<string>APPL</string>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>en</string>
 	<key>UISupportedInterfaceOrientations~ipad</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>
@@ -57,7 +55,13 @@
 		<string>UIInterfaceOrientationLandscapeLeft</string>
 		<string>UIInterfaceOrientationLandscapeRight</string>
 	</array>
-	<key>CFBundleShortVersionString</key>
-	<string>$(FLUTTER_BUILD_NAME)</string>
+	<key>NSBonjourServices</key>
+	<array>
+		<string></string>
+	</array>
+	<key>UIViewControllerBasedStatusBarAppearance</key>
+	<false/>
+	<key>NSLocalNetworkUsageDescription</key>
+	<string>Allow Flutter tools on your computer to connect and debug your application.</string>
 </dict>
 </plist>
diff --git a/example/lib/headless_in_app_webview.screen.dart b/example/lib/headless_in_app_webview.screen.dart
index 6b33cef3..00d39b9c 100755
--- a/example/lib/headless_in_app_webview.screen.dart
+++ b/example/lib/headless_in_app_webview.screen.dart
@@ -11,7 +11,7 @@ class HeadlessInAppWebViewExampleScreen extends StatefulWidget {
 }
 
 class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebViewExampleScreen> {
-  HeadlessInAppWebView headlessWebView;
+  HeadlessInAppWebView? headlessWebView;
   String url = "";
 
   @override
@@ -22,7 +22,7 @@ class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebView
       initialUrl: "https://flutter.dev/",
       initialOptions: InAppWebViewGroupOptions(
         crossPlatform: InAppWebViewOptions(
-          debuggingEnabled: true,
+
         ),
       ),
       onWebViewCreated: (controller) {
@@ -34,19 +34,19 @@ class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebView
       onLoadStart: (controller, url) async {
         print("onLoadStart $url");
         setState(() {
-          this.url = url;
+          this.url = url ?? '';
         });
       },
       onLoadStop: (controller, url) async {
         print("onLoadStop $url");
         setState(() {
-          this.url = url;
+          this.url = url ?? '';
         });
       },
-      onUpdateVisitedHistory: (InAppWebViewController controller, String url, bool androidIsReload) {
+      onUpdateVisitedHistory: (controller, url, androidIsReload) {
         print("onUpdateVisitedHistory $url");
         setState(() {
-          this.url = url;
+          this.url = url ?? '';
         });
       },
     );
@@ -55,7 +55,7 @@ class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebView
   @override
   void dispose() {
     super.dispose();
-    headlessWebView.dispose();
+    headlessWebView?.dispose();
   }
 
   @override
@@ -76,8 +76,8 @@ class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebView
           Center(
             child: RaisedButton(
               onPressed: () async {
-                await headlessWebView.dispose();
-                await headlessWebView.run();
+                await headlessWebView?.dispose();
+                await headlessWebView?.run();
               },
               child: Text("Run HeadlessInAppWebView")),
           ),
@@ -85,7 +85,7 @@ class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebView
             child: RaisedButton(
               onPressed: () async {
                 try {
-                  await headlessWebView.webViewController.evaluateJavascript(source: """console.log('Here is the message!');""");
+                  await headlessWebView?.webViewController.evaluateJavascript(source: """console.log('Here is the message!');""");
                 } on MissingPluginException catch(e) {
                   print("HeadlessInAppWebView is not running. Click on \"Run HeadlessInAppWebView\"!");
                 }
@@ -95,7 +95,7 @@ class _HeadlessInAppWebViewExampleScreenState extends State<HeadlessInAppWebView
           Center(
             child: RaisedButton(
               onPressed: () {
-                headlessWebView.dispose();
+                headlessWebView?.dispose();
               },
               child: Text("Dispose HeadlessInAppWebView")),
           )
diff --git a/example/lib/in_app_browser_example.screen.dart b/example/lib/in_app_browser_example.screen.dart
index dbcea3ae..69b3ea88 100755
--- a/example/lib/in_app_browser_example.screen.dart
+++ b/example/lib/in_app_browser_example.screen.dart
@@ -12,22 +12,22 @@ class MyInAppBrowser extends InAppBrowser {
   }
 
   @override
-  Future onLoadStart(String url) async {
+  Future onLoadStart(url) async {
     print("\n\nStarted $url\n\n");
   }
 
   @override
-  Future onLoadStop(String url) async {
+  Future onLoadStop(url) async {
     print("\n\nStopped $url\n\n");
   }
 
   @override
-  void onLoadError(String url, int code, String message) {
+  void onLoadError(url, code, message) {
     print("Can't load $url.. Error: $message");
   }
 
   @override
-  void onProgressChanged(int progress) {
+  void onProgressChanged(progress) {
     print("Progress: $progress");
   }
 
@@ -38,27 +38,27 @@ class MyInAppBrowser extends InAppBrowser {
 
   @override
   Future<ShouldOverrideUrlLoadingAction> shouldOverrideUrlLoading(
-      ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest) async {
+      shouldOverrideUrlLoadingRequest) async {
     print("\n\nOverride ${shouldOverrideUrlLoadingRequest.url}\n\n");
     return ShouldOverrideUrlLoadingAction.ALLOW;
   }
 
   @override
-  void onLoadResource(LoadedResource response) {
+  void onLoadResource(response) {
     print("Started at: " +
         response.startTime.toString() +
         "ms ---> duration: " +
         response.duration.toString() +
         "ms " +
-        response.url);
+        response.url!);
   }
 
   @override
-  void onConsoleMessage(ConsoleMessage consoleMessage) {
+  void onConsoleMessage(consoleMessage) {
     print("""
     console output:
       message: ${consoleMessage.message}
-      messageLevel: ${consoleMessage.messageLevel.toValue()}
+      messageLevel: ${consoleMessage.messageLevel!.toValue()}
    """);
   }
 }
@@ -96,7 +96,6 @@ class _InAppBrowserExampleScreenState extends State<InAppBrowserExampleScreen> {
                           options: InAppBrowserClassOptions(
                               inAppWebViewGroupOptions: InAppWebViewGroupOptions(
                                   crossPlatform: InAppWebViewOptions(
-                            debuggingEnabled: true,
                             useShouldOverrideUrlLoading: true,
                             useOnLoadResource: true,
                           ))));
diff --git a/example/lib/in_app_webiew_example.screen.dart b/example/lib/in_app_webiew_example.screen.dart
index 1dc03d5d..2f4349b0 100755
--- a/example/lib/in_app_webiew_example.screen.dart
+++ b/example/lib/in_app_webiew_example.screen.dart
@@ -1,4 +1,3 @@
-import 'dart:developer';
 import 'dart:io';
 
 import 'package:flutter/material.dart';
@@ -14,8 +13,8 @@ class InAppWebViewExampleScreen extends StatefulWidget {
 }
 
 class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
-  InAppWebViewController webView;
-  ContextMenu contextMenu;
+  InAppWebViewController? webView;
+  late ContextMenu contextMenu;
   String url = "";
   double progress = 0;
   CookieManager _cookieManager = CookieManager.instance();
@@ -28,8 +27,8 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
       menuItems: [
         ContextMenuItem(androidId: 1, iosId: "1", title: "Special", action: () async {
           print("Menu item Special clicked!");
-          print(await webView.getSelectedText());
-          await webView.clearFocus();
+          print(await webView?.getSelectedText());
+          await webView?.clearFocus();
         })
       ],
       options: ContextMenuOptions(
@@ -38,7 +37,7 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
       onCreateContextMenu: (hitTestResult) async {
         print("onCreateContextMenu");
         print(hitTestResult.extra);
-        print(await webView.getSelectedText());
+        print(await webView?.getSelectedText());
       },
       onHideContextMenu: () {
         print("onHideContextMenu");
@@ -81,26 +80,25 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
                   BoxDecoration(border: Border.all(color: Colors.blueAccent)),
                   child: InAppWebView(
                     // contextMenu: contextMenu,
-                    initialUrl: "https://github.com/flutter",
+                    initialUrl: "https://flutter.dev/",
                     // initialFile: "assets/index.html",
                     initialHeaders: {},
                     initialOptions: InAppWebViewGroupOptions(
                       crossPlatform: InAppWebViewOptions(
-                        debuggingEnabled: true,
-                        useShouldOverrideUrlLoading: true,
+                        useShouldOverrideUrlLoading: false
                       ),
                       android: AndroidInAppWebViewOptions(
                         useHybridComposition: true
                       )
                     ),
-                    onWebViewCreated: (InAppWebViewController controller) {
+                    onWebViewCreated: (controller) {
                       webView = controller;
                       print("onWebViewCreated");
                     },
-                    onLoadStart: (InAppWebViewController controller, String url) {
+                    onLoadStart: (controller, url) {
                       print("onLoadStart $url");
                       setState(() {
-                        this.url = url;
+                        this.url = url ?? '';
                       });
                     },
                     shouldOverrideUrlLoading: (controller, shouldOverrideUrlLoadingRequest) async {
@@ -122,21 +120,21 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
 
                       return ShouldOverrideUrlLoadingAction.ALLOW;
                     },
-                    onLoadStop: (InAppWebViewController controller, String url) async {
+                    onLoadStop: (controller, url) async {
                       print("onLoadStop $url");
                       setState(() {
-                        this.url = url;
+                        this.url = url ?? '';
                       });
                     },
-                    onProgressChanged: (InAppWebViewController controller, int progress) {
+                    onProgressChanged: (controller, progress) {
                       setState(() {
                         this.progress = progress / 100;
                       });
                     },
-                    onUpdateVisitedHistory: (InAppWebViewController controller, String url, bool androidIsReload) {
+                    onUpdateVisitedHistory: (controller, url, androidIsReload) {
                       print("onUpdateVisitedHistory $url");
                       setState(() {
-                        this.url = url;
+                        this.url = url ?? '';
                       });
                     },
                     onConsoleMessage: (controller, consoleMessage) {
@@ -151,25 +149,19 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
                   RaisedButton(
                     child: Icon(Icons.arrow_back),
                     onPressed: () {
-                      if (webView != null) {
-                        webView.goBack();
-                      }
+                      webView?.goBack();
                     },
                   ),
                   RaisedButton(
                     child: Icon(Icons.arrow_forward),
                     onPressed: () {
-                      if (webView != null) {
-                        webView.goForward();
-                      }
+                      webView?.goForward();
                     },
                   ),
                   RaisedButton(
                     child: Icon(Icons.refresh),
                     onPressed: () {
-                      if (webView != null) {
-                        webView.reload();
-                      }
+                      webView?.reload();
                     },
                   ),
                 ],
diff --git a/example/lib/main.dart b/example/lib/main.dart
index 82f75941..ebf56810 100755
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -1,6 +1,8 @@
 import 'dart:async';
+import 'dart:io';
 
 import 'package:flutter/material.dart';
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 
 import 'package:flutter_inappwebview_example/chrome_safari_browser_example.screen.dart';
 import 'package:flutter_inappwebview_example/headless_in_app_webview.screen.dart';
@@ -15,10 +17,13 @@ Future main() async {
 //  await Permission.camera.request();
 //  await Permission.storage.request();
   // await localhostServer.start();
+  if (Platform.isAndroid) {
+    await AndroidInAppWebViewController.setWebContentsDebuggingEnabled(true);
+  }
   runApp(MyApp());
 }
 
-Drawer myDrawer({@required BuildContext context}) {
+Drawer myDrawer({required BuildContext context}) {
   return Drawer(
     child: ListView(
       padding: EdgeInsets.zero,
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 6b0beb76..16495922 100755
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -10,8 +10,8 @@ description: Demonstrates how to use the flutter_inappwebview plugin.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
-  flutter: ">=1.10.0 <2.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
+  flutter: ">=1.22.0"
 
 dependencies:
   flutter:
@@ -19,20 +19,26 @@ dependencies:
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
-  cupertino_icons: ^0.1.2
-  flutter_downloader: ^1.4.4
-  path_provider: ^1.6.9
-  permission_handler: ^5.0.0+hotfix.6
-  url_launcher: ^5.4.11
+  cupertino_icons: ^1.0.2
+  flutter_downloader: ^1.5.2
+  path_provider: ^1.6.27
+  permission_handler: ^5.0.1+1
+  url_launcher: ^6.0.0-nullsafety.4
   # connectivity: ^0.4.5+6
   flutter_inappwebview:
     path: ../
 
 dev_dependencies:
-  e2e: "^0.2.0"
+  flutter_test:
+    sdk: flutter
   flutter_driver:
     sdk: flutter
-  test: any
+  # integration_test: ^1.0.2+1
+  integration_test:
+    git:
+      url: https://github.com/flutter/plugins.git
+      path: packages/integration_test
+  pedantic: ^1.8.0
 
 # For information on the generic Dart part of this file, see the
 # following page: https://www.dartlang.org/tools/pub/pubspec
@@ -53,6 +59,8 @@ flutter:
     - assets/css/
     - assets/images/
     - assets/favicon.ico
+    - assets/sample_audio.ogg
+    - assets/sample_video.mp4
     - test_assets/certificate.pfx
     - test_assets/in_app_webview_initial_file_test.html
     - test_assets/in_app_webview_on_load_resource_test.html
@@ -64,6 +72,8 @@ flutter:
     - test_assets/css/
     - test_assets/images/
     - test_assets/favicon.ico
+    - test_assets/sample_audio.ogg
+    - test_assets/sample_video.mp4
 
   # To add assets to your application, add an assets section, like this:
   # assets:
diff --git a/example/test_assets/sample_audio.ogg b/example/test_assets/sample_audio.ogg
new file mode 100644
index 00000000..27e17104
Binary files /dev/null and b/example/test_assets/sample_audio.ogg differ
diff --git a/example/test_assets/sample_video.mp4 b/example/test_assets/sample_video.mp4
new file mode 100644
index 00000000..a203d0cd
Binary files /dev/null and b/example/test_assets/sample_video.mp4 differ
diff --git a/example/test_driver/.env.dart b/example/test_driver/.env.dart
deleted file mode 100755
index 403c309b..00000000
--- a/example/test_driver/.env.dart
+++ /dev/null
@@ -1 +0,0 @@
-final environment = {"NODE_SERVER_IP":"192.168.1.122"};
\ No newline at end of file
diff --git a/example/test_driver/app.dart b/example/test_driver/app.dart
deleted file mode 100755
index e5731cfa..00000000
--- a/example/test_driver/app.dart
+++ /dev/null
@@ -1,11 +0,0 @@
-import 'package:flutter_driver/driver_extension.dart';
-import 'main_test.dart' as app;
-
-void main() {
-  // This line enables the extension.
-  enableFlutterDriverExtension();
-
-  // Call the `main()` function of the app, or call `runApp` with
-  // any widget you are interested in testing.
-  app.main();
-}
\ No newline at end of file
diff --git a/example/test_driver/app_test.dart b/example/test_driver/app_test.dart
deleted file mode 100755
index a8f0f006..00000000
--- a/example/test_driver/app_test.dart
+++ /dev/null
@@ -1,532 +0,0 @@
-// Imports the Flutter Driver API.
-import 'dart:async';
-import 'dart:io';
-
-import 'package:flutter_driver/flutter_driver.dart';
-import 'package:test/test.dart';
-import '.env.dart';
-
-void main() {
-
-  group('Flutter InAppWebView', () {
-    FlutterDriver driver;
-
-    // Connect to the Flutter driver before running any tests.
-    setUpAll(() async {
-      driver = await FlutterDriver.connect();
-      await driver.setTextEntryEmulation(enabled: true);
-    });
-
-    // Close the connection to the driver after the tests have completed.
-    tearDownAll(() async {
-      if (driver != null) {
-        driver.close();
-      }
-    });
-
-    test('InAppWebViewInitialUrlTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewInitialFileTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewInitialUrlTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String url = await driver.getText(appBarTitle);
-      expect(url, "https://flutter.dev/");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewInitialFileTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewInitialDataTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewInitialFileTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewInitialDataTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnProgressChangedTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewInitialDataTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnProgressChangedTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnScrollChangedTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnProgressChangedTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnScrollChangedTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnLoadResourceTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnScrollChangedTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnLoadResourceTest', () async {
-      List<String> resourceList = [
-        "https://getbootstrap.com/docs/4.3/dist/css/bootstrap.min.css",
-        "https://code.jquery.com/jquery-3.3.1.min.js",
-        "https://via.placeholder.com/100x50"
-      ];
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewJavaScriptHandlerTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnLoadResourceTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      for (String resource in resourceList) {
-        expect(true, title.contains(resource));
-      }
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewJavaScriptHandlerTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewAjaxTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewJavaScriptHandlerTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(true, !title.contains("false"));
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewAjaxTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewFetchTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewAjaxTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "Lorenzo Pichilli Lorenzo Pichilli");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewFetchTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnLoadResourceCustomSchemeTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewFetchTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(true, title.contains("Lorenzo Pichilli") && title.contains("200"));
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnLoadResourceCustomSchemeTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewShouldOverrideUrlLoadingTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnLoadResourceCustomSchemeTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewShouldOverrideUrlLoadingTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnConsoleMessageTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewShouldOverrideUrlLoadingTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String url = await driver.getText(appBarTitle);
-      expect(url, "https://flutter.dev/");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnConsoleMessageTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnDownloadStartTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnConsoleMessageTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "message LOG");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnDownloadStartTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnCreateWindowTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnDownloadStartTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String url = await driver.getText(appBarTitle);
-      expect(url, "http://${environment["NODE_SERVER_IP"]}:8082/test-download-file");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnCreateWindowTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnJsDialogTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnCreateWindowTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String url = await driver.getText(appBarTitle);
-      expect(url, "https://flutter.dev/");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnJsDialogTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-      final alertButtonOk = find.byValueKey('AlertButtonOk');
-      final confirmButtonCancel = find.byValueKey('ConfirmButtonCancel');
-      final confirmButtonOk = find.byValueKey('ConfirmButtonOk');
-      final promptTextField = find.byValueKey('PromptTextField');
-      final promptButtonCancel = find.byValueKey('PromptButtonCancel');
-      final promptButtonOk = find.byValueKey('PromptButtonOk');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnSafeBrowsingHitTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnJsDialogTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      await driver.tap(alertButtonOk);
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "alert");
-
-      await Future.delayed(const Duration(milliseconds: 500));
-
-      await driver.tap(confirmButtonOk);
-
-      title = await driver.getText(appBarTitle);
-      expect(title, "confirm true");
-
-      await Future.delayed(const Duration(milliseconds: 500));
-
-      await driver.tap(promptTextField);
-      await driver.enterText("new value");
-      await driver.waitFor(find.text("new value"));
-
-      await driver.tap(promptButtonOk);
-
-      title = await driver.getText(appBarTitle);
-      expect(title, "prompt new value");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnSafeBrowsingHitTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnReceivedHttpAuthRequestTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnSafeBrowsingHitTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String url = await driver.getText(appBarTitle);
-      if (Platform.isAndroid)
-        expect(url, "chrome://safe-browsing/match?type=malware");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnReceivedHttpAuthRequestTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewSslRequestTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnReceivedHttpAuthRequestTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "Authorized");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewSslRequestTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnFindResultReceivedTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewSslRequestTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "Authorized");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnFindResultReceivedTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnNavigationStateChangeTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnFindResultReceivedTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "2");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnNavigationStateChangeTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnLoadErrorTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnNavigationStateChangeTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(true, title.contains("first-push") && title.contains("second-push"));
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnLoadErrorTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewOnLoadHttpErrorTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnLoadErrorTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      if (Platform.isAndroid) {
-        expect(title, "-2");
-      } else if (Platform.isIOS) {
-        expect(title, "-1022");
-      }
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewOnLoadHttpErrorTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewCookieManagerTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewOnLoadHttpErrorTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "404");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewCookieManagerTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewHttpAuthCredentialDatabaseTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewCookieManagerTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "myValue true true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewHttpAuthCredentialDatabaseTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      final sideMenuButton = find.byValueKey('SideMenu');
-      final listTiles = find.byValueKey('ListTiles');
-      final nextTest = find.byValueKey('InAppWebViewContentBlockerTest');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewHttpAuthCredentialDatabaseTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "Authorized true true");
-
-      await driver.tap(sideMenuButton);
-      await driver.scrollUntilVisible(listTiles, nextTest, dyScroll: -300.0);
-      await driver.tap(nextTest);
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-    test('InAppWebViewContentBlockerTest', () async {
-      final appBarTitle = find.byValueKey('AppBarTitle');
-
-      while((await driver.getText(appBarTitle)) == "InAppWebViewContentBlockerTest") {
-        await Future.delayed(const Duration(milliseconds: 500));
-      }
-
-      String title = await driver.getText(appBarTitle);
-      expect(title, "true");
-    }, timeout: new Timeout(new Duration(minutes: 5)));
-
-  });
-}
\ No newline at end of file
diff --git a/example/test_driver/custom_widget_test.dart b/example/test_driver/custom_widget_test.dart
deleted file mode 100755
index 1115fd09..00000000
--- a/example/test_driver/custom_widget_test.dart
+++ /dev/null
@@ -1,26 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:flutter/widgets.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-class WidgetTest extends StatefulWidget {
-  final WidgetTestState state = WidgetTestState();
-
-  WidgetTest({Key key}): super(key: key);
-
-  @override
-  WidgetTestState createState() {
-    return state;
-  }
-}
-
-class WidgetTestState extends State<WidgetTest> {
-  final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>();
-  InAppWebViewController webView;
-  String appBarTitle;
-
-  @override
-  Widget build(BuildContext context) {
-    return null;
-  }
-}
\ No newline at end of file
diff --git a/example/test_driver/in_app_webview_ajax_test.dart b/example/test_driver/in_app_webview_ajax_test.dart
deleted file mode 100755
index 2cc08dd4..00000000
--- a/example/test_driver/in_app_webview_ajax_test.dart
+++ /dev/null
@@ -1,112 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-import '.env.dart';
-
-class InAppWebViewAjaxTest extends WidgetTest {
-  final InAppWebViewAjaxTestState state = InAppWebViewAjaxTestState();
-
-  @override
-  InAppWebViewAjaxTestState createState() => state;
-}
-
-class InAppWebViewAjaxTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewAjaxTest";
-  int totTests = 2;
-  int testsDone = 0;
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialData: InAppWebViewInitialData(data: """
-<!doctype html>
-<html lang="en">
-    <head>
-        <meta charset="UTF-8">
-        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
-        <meta http-equiv="X-UA-Compatible" content="ie=edge">
-        <title>InAppWebViewAjaxTest</title>
-    </head>
-    <body>
-        <h1>InAppWebViewAjaxTest</h1>
-        <script>
-          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
-            var xhttp = new XMLHttpRequest();
-            xhttp.open("POST", "http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post");
-            xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
-            xhttp.send("firstname=Foo&lastname=Bar");
-
-            var xhttp2 = new XMLHttpRequest();
-            xhttp2.open("GET", "http://${environment["NODE_SERVER_IP"]}:8082/test-download-file");
-            xhttp2.send();
-          });
-        </script>
-    </body>
-</html>
-                    """),
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true,
-                            useShouldInterceptAjaxRequest: true,
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    shouldInterceptAjaxRequest: (InAppWebViewController controller, AjaxRequest ajaxRequest) async {
-                      if (ajaxRequest.url.endsWith("/test-ajax-post")) {
-                        ajaxRequest.responseType = 'json';
-                        ajaxRequest.data = "firstname=Lorenzo&lastname=Pichilli";
-                      }
-                      return ajaxRequest;
-                    },
-                    onAjaxReadyStateChange: (InAppWebViewController controller, AjaxRequest ajaxRequest) async {
-                      if (ajaxRequest.readyState == AjaxRequestReadyState.DONE && ajaxRequest.status == 200 && ajaxRequest.url.endsWith("/test-ajax-post")) {
-                        Map<String, Object> res = ajaxRequest.response;
-                        appBarTitle = (appBarTitle == "InAppWebViewAjaxTest") ? res['fullname'] : appBarTitle + " " + res['fullname'];
-                        updateCountTest(context: context);
-                      }
-                      return AjaxRequestAction.PROCEED;
-                    },
-                    onAjaxProgress: (InAppWebViewController controller, AjaxRequest ajaxRequest) async {
-                      if (ajaxRequest.event.type == AjaxRequestEventType.LOAD && ajaxRequest.url.endsWith("/test-ajax-post")) {
-                        Map<String, Object> res = ajaxRequest.response;
-                        appBarTitle = (appBarTitle == "InAppWebViewAjaxTest") ? res['fullname'] : appBarTitle + " " + res['fullname'];
-                        updateCountTest(context: context);
-                      }
-                      return AjaxRequestAction.PROCEED;
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-
-  void updateCountTest({@required BuildContext context}) {
-    testsDone++;
-    if (testsDone == totTests) {
-      setState(() {  });
-    }
-  }
-}
diff --git a/example/test_driver/in_app_webview_content_blocker_test.dart b/example/test_driver/in_app_webview_content_blocker_test.dart
deleted file mode 100755
index 7b738b72..00000000
--- a/example/test_driver/in_app_webview_content_blocker_test.dart
+++ /dev/null
@@ -1,70 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewContentBlockerTest extends WidgetTest {
-  final InAppWebViewContentBlockerTestState state = InAppWebViewContentBlockerTestState();
-
-  @override
-  InAppWebViewContentBlockerTestState createState() => state;
-}
-
-class InAppWebViewContentBlockerTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewContentBlockerTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true,
-                            contentBlockers: [
-                              ContentBlocker(
-                                  trigger: ContentBlockerTrigger(
-                                      urlFilter: ".*",
-                                      resourceType: [
-                                        ContentBlockerTriggerResourceType.IMAGE,
-                                        ContentBlockerTriggerResourceType.STYLE_SHEET
-                                      ],
-                                      ifTopUrl: [
-                                        "https://flutter.dev/"
-                                      ]),
-                                  action: ContentBlockerAction(
-                                      type: ContentBlockerActionType.BLOCK))
-                            ]
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = "true";
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_cookie_manager_test.dart b/example/test_driver/in_app_webview_cookie_manager_test.dart
deleted file mode 100755
index 37edacb4..00000000
--- a/example/test_driver/in_app_webview_cookie_manager_test.dart
+++ /dev/null
@@ -1,69 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewCookieManagerTest extends WidgetTest {
-  final InAppWebViewCookieManagerTestState state = InAppWebViewCookieManagerTestState();
-
-  @override
-  InAppWebViewCookieManagerTestState createState() => state;
-}
-
-class InAppWebViewCookieManagerTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewCookieManagerTest";
-  CookieManager cookieManager = CookieManager.instance();
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) async {
-                      var title = "";
-                      await cookieManager.getCookies(url: url);
-                      await cookieManager.setCookie(url: url, name: "myCookie", value: "myValue");
-                      Cookie cookie = await cookieManager.getCookie(url: url, name: "myCookie");
-                      title = cookie.value.toString();
-                      await cookieManager.deleteCookie(url: url, name: "myCookie");
-                      cookie = await cookieManager.getCookie(url: url, name: "myCookie");
-                      title += " " + ((cookie == null) ? "true" : "false");
-                      await cookieManager.deleteCookies(url: url);
-                      List<Cookie> cookies = await cookieManager.getCookies(url: url);
-                      title += " " + ((cookies.length == 0) ? "true" : "false");
-
-                      setState(() {
-                        appBarTitle = title;
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_fetch_test.dart b/example/test_driver/in_app_webview_fetch_test.dart
deleted file mode 100755
index c6b46057..00000000
--- a/example/test_driver/in_app_webview_fetch_test.dart
+++ /dev/null
@@ -1,127 +0,0 @@
-import 'dart:convert';
-
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-import '.env.dart';
-
-class InAppWebViewFetchTest extends WidgetTest {
-  final InAppWebViewFetchTestState state = InAppWebViewFetchTestState();
-
-  @override
-  InAppWebViewFetchTestState createState() => state;
-}
-
-class InAppWebViewFetchTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewFetchTest";
-  int totTests = 2;
-  int testsDone = 0;
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialData: InAppWebViewInitialData(data: """
-<!doctype html>
-<html lang="en">
-    <head>
-        <meta charset="UTF-8">
-        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
-        <meta http-equiv="X-UA-Compatible" content="ie=edge">
-        <title>InAppWebViewFetchTest</title>
-    </head>
-    <body>
-        <h1>InAppWebViewFetchTest</h1>
-        <script>
-          window.addEventListener('flutterInAppWebViewPlatformReady', function(event) {
-            fetch(new Request("http://${environment["NODE_SERVER_IP"]}:8082/test-download-file")).then(function(response) {
-                window.flutter_inappwebview.callHandler('fetchGet', response.status);
-            }).catch(function(error) {
-                window.flutter_inappwebview.callHandler('fetchGet', "ERROR: " + error);
-            });
-
-            fetch("http://${environment["NODE_SERVER_IP"]}:8082/test-ajax-post", {
-                method: 'POST',
-                body: JSON.stringify({
-                    firstname: 'Foo',
-                    lastname: 'Bar'
-                }),
-                headers: {
-                  'Content-Type': 'application/json'
-                }
-            }).then(function(response) {
-                response.json().then(function(value) {
-					window.flutter_inappwebview.callHandler('fetchPost', value);
-				}).catch(function(error) {
-				    window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
-				});
-            }).catch(function(error) {
-                window.flutter_inappwebview.callHandler('fetchPost', "ERROR: " + error);
-            });
-          });
-        </script>
-    </body>
-</html>
-                    """),
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true,
-                            useShouldInterceptFetchRequest: true,
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-
-                      webView.addJavaScriptHandler(handlerName: "fetchGet", callback: (args) {
-                        appBarTitle = (appBarTitle == "InAppWebViewFetchTest") ? args[0].toString() : appBarTitle + " " + args[0].toString();
-                        updateCountTest(context: context);
-                      });
-
-                      webView.addJavaScriptHandler(handlerName: "fetchPost", callback: (args) {
-                        appBarTitle = (appBarTitle == "InAppWebViewFetchTest") ? args[0]["fullname"] : appBarTitle + " " + args[0]["fullname"];
-                        updateCountTest(context: context);
-                      });
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    shouldInterceptFetchRequest: (InAppWebViewController controller, FetchRequest fetchRequest) async {
-                      if (fetchRequest.url.endsWith("/test-ajax-post")) {
-                        fetchRequest.body = utf8.encode("""{
-                          "firstname": "Lorenzo",
-                          "lastname": "Pichilli"
-                        }
-                        """);
-                      }
-                      return fetchRequest;
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-
-  void updateCountTest({@required BuildContext context}) {
-    testsDone++;
-    if (testsDone == totTests) {
-      setState(() {  });
-    }
-  }
-}
diff --git a/example/test_driver/in_app_webview_http_auth_credential_database_test.dart b/example/test_driver/in_app_webview_http_auth_credential_database_test.dart
deleted file mode 100755
index 14fc2c2c..00000000
--- a/example/test_driver/in_app_webview_http_auth_credential_database_test.dart
+++ /dev/null
@@ -1,79 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-import '.env.dart';
-
-class InAppWebViewHttpAuthCredentialDatabaseTest extends WidgetTest {
-  final InAppWebViewHttpAuthCredentialDatabaseTestState state = InAppWebViewHttpAuthCredentialDatabaseTestState();
-
-  @override
-  InAppWebViewHttpAuthCredentialDatabaseTestState createState() => state;
-}
-
-class InAppWebViewHttpAuthCredentialDatabaseTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewHttpAuthCredentialDatabaseTest";
-  HttpAuthCredentialDatabase httpAuthCredentialDatabase = HttpAuthCredentialDatabase.instance();
-
-  @override
-  Widget build(BuildContext context) {
-
-    httpAuthCredentialDatabase.setHttpAuthCredential(
-        protectionSpace: ProtectionSpace(host: environment["NODE_SERVER_IP"], protocol: "http", realm: "Node", port: 8081),
-        credential: HttpAuthCredential(username: "USERNAME", password: "PASSWORD")
-    );
-
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "http://${environment["NODE_SERVER_IP"]}:8081/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) async {
-                      var title = "";
-                      String h1Content = await controller.evaluateJavascript(source: "document.body.querySelector('h1').textContent");
-                      title = h1Content;
-                      var credentials = await httpAuthCredentialDatabase.getHttpAuthCredentials(protectionSpace:
-                        ProtectionSpace(host: environment["NODE_SERVER_IP"], protocol: "http", realm: "Node", port: 8081)
-                      );
-                      title += " " + ((credentials.length == 1) ? "true" : "false");
-                      await httpAuthCredentialDatabase.clearAllAuthCredentials();
-                      credentials = await httpAuthCredentialDatabase.getHttpAuthCredentials(protectionSpace:
-                        ProtectionSpace(host: environment["NODE_SERVER_IP"], protocol: "http", realm: "Node", port: 8081)
-                      );
-                      title += " " + ((credentials.length == 0) ? "true" : "false");
-                      setState(() {
-                        appBarTitle = title;
-                      });
-                    },
-                    onReceivedHttpAuthRequest: (InAppWebViewController controller, HttpAuthChallenge challenge) async {
-                      return new HttpAuthResponse(action: HttpAuthResponseAction.USE_SAVED_HTTP_AUTH_CREDENTIALS);
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_initial_data_test.dart b/example/test_driver/in_app_webview_initial_data_test.dart
deleted file mode 100755
index 4075ee0d..00000000
--- a/example/test_driver/in_app_webview_initial_data_test.dart
+++ /dev/null
@@ -1,92 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewInitialDataTest extends WidgetTest {
-  final InAppWebViewInitialDataTestState state = InAppWebViewInitialDataTestState();
-
-  @override
-  InAppWebViewInitialDataTestState createState() => state;
-}
-
-class InAppWebViewInitialDataTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewInitialDataTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialData: InAppWebViewInitialData(data: """
-<!doctype html>
-<html lang="en">
-    <head>
-        <meta charset="UTF-8">
-        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
-        <meta http-equiv="X-UA-Compatible" content="ie=edge">
-        <title>InAppWebViewInitialDataTest</title>
-        <link rel="stylesheet" href="https://getbootstrap.com/docs/4.3/dist/css/bootstrap.min.css">
-        <link rel="stylesheet" href="css/style.css">
-        <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
-        <link rel="shortcut icon" href="favicon.ico">
-    </head>
-    <body class="text-center">
-        <div class="cover-container d-flex w-100 h-100 p-3 mx-auto flex-column">
-            <header class="masthead mb-auto">
-                <div class="inner">
-                    <h3 class="masthead-brand">InAppWebViewInitialDataTest</h3>
-                    <nav class="nav nav-masthead justify-content-center">
-                        <a class="nav-link active" href="index.html">Home</a>
-                        <a class="nav-link" href="page-1.html">Page 1</a>
-                        <a class="nav-link" href="page-2.html">Page 2</a>
-                    </nav>
-                </div>
-            </header>
-
-            <main role="main" class="inner cover">
-                <h1 class="cover-heading">InAppWebViewInitialFileTest</h1>
-                <img src="images/flutter-logo.svg" alt="flutter logo">
-                <p>
-                    <img src="https://via.placeholder.com/100x50" alt="placeholder 100x50">
-                </p>
-                <a id="link" href="https://github.com/pichillilorenzo/flutter_inappwebview">flutter_inappwebview</a>
-            </main>
-        </div>
-    </body>
-</html>
-                    """),
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = "true";
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_initial_file_test.dart b/example/test_driver/in_app_webview_initial_file_test.dart
deleted file mode 100755
index 7f2de7db..00000000
--- a/example/test_driver/in_app_webview_initial_file_test.dart
+++ /dev/null
@@ -1,55 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewInitialFileTest extends WidgetTest {
-  final InAppWebViewInitialFileTestState state = InAppWebViewInitialFileTestState();
-
-  @override
-  InAppWebViewInitialFileTestState createState() => state;
-}
-
-class InAppWebViewInitialFileTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewInitialFileTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_initial_file_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = "true";
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_initial_url_test.dart b/example/test_driver/in_app_webview_initial_url_test.dart
deleted file mode 100755
index 486cdf99..00000000
--- a/example/test_driver/in_app_webview_initial_url_test.dart
+++ /dev/null
@@ -1,56 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewInitialUrlTest extends WidgetTest {
-  final InAppWebViewInitialUrlTestState state = InAppWebViewInitialUrlTestState();
-
-  @override
-  InAppWebViewInitialUrlTestState createState() => state;
-}
-
-class InAppWebViewInitialUrlTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewInitialUrlTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = url;
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_javascript_handler_test.dart b/example/test_driver/in_app_webview_javascript_handler_test.dart
deleted file mode 100755
index 1fac7e69..00000000
--- a/example/test_driver/in_app_webview_javascript_handler_test.dart
+++ /dev/null
@@ -1,84 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class Foo {
-  String bar;
-  String baz;
-
-  Foo({this.bar, this.baz});
-
-  Map<String, dynamic> toJson() {
-    return {
-      'bar': this.bar,
-      'baz': this.baz
-    };
-  }
-}
-
-class InAppWebViewJavaScriptHandlerTest extends WidgetTest {
-  final InAppWebViewJavaScriptHandlerTestState state = InAppWebViewJavaScriptHandlerTestState();
-
-  @override
-  InAppWebViewJavaScriptHandlerTestState createState() => state;
-}
-
-class InAppWebViewJavaScriptHandlerTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewJavaScriptHandlerTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_javascript_handler_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-
-                      controller.addJavaScriptHandler(handlerName:'handlerFoo', callback: (args) {
-                        appBarTitle = (args.length == 0).toString();
-                        return Foo(bar: 'bar_value', baz: 'baz_value');
-                      });
-
-                      controller.addJavaScriptHandler(handlerName: 'handlerFooWithArgs', callback: (args) {
-                        appBarTitle += " " + (args[0] is int).toString();
-                        appBarTitle += " " + (args[1] is bool).toString();
-                        appBarTitle += " " + (args[2] is List).toString();
-                        appBarTitle += " " + (args[2] is List).toString();
-                        appBarTitle += " " + (args[3] is Map).toString();
-                        appBarTitle += " " + (args[4] is Map).toString();
-                        setState(() { });
-                      });
-
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_console_message_test.dart b/example/test_driver/in_app_webview_on_console_message_test.dart
deleted file mode 100755
index 2c89b584..00000000
--- a/example/test_driver/in_app_webview_on_console_message_test.dart
+++ /dev/null
@@ -1,58 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnConsoleMessageTest extends WidgetTest {
-  final InAppWebViewOnConsoleMessageTestState state = InAppWebViewOnConsoleMessageTestState();
-
-  @override
-  InAppWebViewOnConsoleMessageTestState createState() => state;
-}
-
-class InAppWebViewOnConsoleMessageTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnConsoleMessageTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_on_console_message_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onConsoleMessage: (InAppWebViewController controller, ConsoleMessage consoleMessage) {
-                      setState(() {
-                        appBarTitle = consoleMessage.message + " " + consoleMessage.messageLevel.toString();
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_create_window_test.dart b/example/test_driver/in_app_webview_on_create_window_test.dart
deleted file mode 100755
index af5c54a8..00000000
--- a/example/test_driver/in_app_webview_on_create_window_test.dart
+++ /dev/null
@@ -1,62 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnCreateWindowTest extends WidgetTest {
-  final InAppWebViewOnCreateWindowTestState state = InAppWebViewOnCreateWindowTestState();
-
-  @override
-  InAppWebViewOnCreateWindowTestState createState() => state;
-}
-
-class InAppWebViewOnCreateWindowTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnCreateWindowTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_on_create_window_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true,
-                            javaScriptCanOpenWindowsAutomatically: true,
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      if (url == "https://flutter.dev/") {
-                        setState(() {
-                          appBarTitle = url;
-                        });
-                      }
-                    },
-                    onCreateWindow: (InAppWebViewController controller, CreateWindowRequest createWindowRequest) async {
-                      controller.loadUrl(url: createWindowRequest.url);
-                      return null;
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_download_start_test.dart b/example/test_driver/in_app_webview_on_download_start_test.dart
deleted file mode 100755
index d1a7d543..00000000
--- a/example/test_driver/in_app_webview_on_download_start_test.dart
+++ /dev/null
@@ -1,79 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-import '.env.dart';
-
-class InAppWebViewOnDownloadStartTest extends WidgetTest {
-  final InAppWebViewOnDownloadStartTestState state = InAppWebViewOnDownloadStartTestState();
-
-  @override
-  InAppWebViewOnDownloadStartTestState createState() => state;
-}
-
-class InAppWebViewOnDownloadStartTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnDownloadStartTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialData: InAppWebViewInitialData(data: """
-<!doctype html>
-<html lang="en">
-    <head>
-        <meta charset="UTF-8">
-        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
-        <meta http-equiv="X-UA-Compatible" content="ie=edge">
-        <title>InAppWebViewOnDownloadStartTest</title>
-    </head>
-    <body>
-        <h1>InAppWebViewOnDownloadStartTest</h1>
-        <a id="download-file" href="http://${environment["NODE_SERVER_IP"]}:8082/test-download-file">download file</a>
-        <script>
-            window.addEventListener("flutterInAppWebViewPlatformReady", function(event) {
-                document.querySelector("#download-file").click();
-            });
-        </script>
-    </body>
-</html>
-                    """),
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true,
-                            useOnDownloadStart: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onDownloadStart: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = url;
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_find_result_received_test.dart b/example/test_driver/in_app_webview_on_find_result_received_test.dart
deleted file mode 100755
index c601b24b..00000000
--- a/example/test_driver/in_app_webview_on_find_result_received_test.dart
+++ /dev/null
@@ -1,60 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnFindResultReceivedTest extends WidgetTest {
-  final InAppWebViewOnFindResultReceivedTestState state = InAppWebViewOnFindResultReceivedTestState();
-
-  @override
-  InAppWebViewOnFindResultReceivedTestState createState() => state;
-}
-
-class InAppWebViewOnFindResultReceivedTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnFindResultReceivedTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_initial_file_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      controller.findAllAsync(find: "InAppWebViewInitialFileTest");
-                    },
-                    onFindResultReceived: (InAppWebViewController controller, int activeMatchOrdinal, int numberOfMatches, bool isDoneCounting) async {
-                      if (isDoneCounting) {
-                        setState(() {
-                          appBarTitle = numberOfMatches.toString();
-                        });
-                      }
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_js_dialog_test.dart b/example/test_driver/in_app_webview_on_js_dialog_test.dart
deleted file mode 100755
index 65813ef2..00000000
--- a/example/test_driver/in_app_webview_on_js_dialog_test.dart
+++ /dev/null
@@ -1,199 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnJsDialogTest extends WidgetTest {
-  final InAppWebViewOnJsDialogTestState state = InAppWebViewOnJsDialogTestState();
-
-  @override
-  InAppWebViewOnJsDialogTestState createState() => state;
-}
-
-class InAppWebViewOnJsDialogTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnJsDialogTest";
-
-  TextEditingController _textFieldController = TextEditingController();
-
-  @override
-  void dispose() {
-    super.dispose();
-    _textFieldController.dispose();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_on_js_dialog_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-
-                      controller.addJavaScriptHandler(handlerName: 'confirm', callback: (args) {
-                        setState(() {
-                          appBarTitle = "confirm " + ((args[0] is bool && args[0]) ? "true" : "false");
-                        });
-                      });
-
-                      controller.addJavaScriptHandler(handlerName: 'prompt', callback: (args) {
-                        setState(() {
-                          appBarTitle = "prompt " + args[0];
-                        });
-                      });
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = "loaded";
-                      });
-                    },
-                    onJsAlert:
-                        (InAppWebViewController controller, JsAlertRequest jsAlertRequest) async {
-                      JsAlertResponseAction action =
-                      await createAlertDialog(context, jsAlertRequest.message);
-                      return JsAlertResponse(
-                          handledByClient: true, action: action);
-                    },
-                    onJsConfirm:
-                        (InAppWebViewController controller, JsConfirmRequest jsConfirmRequest) async {
-                      JsConfirmResponseAction action =
-                      await createConfirmDialog(context, jsConfirmRequest.message);
-                      return JsConfirmResponse(
-                          handledByClient: true, action: action);
-                    },
-                    onJsPrompt: (InAppWebViewController controller, JsPromptRequest jsPromptRequest) async {
-                      _textFieldController.text = jsPromptRequest.defaultValue;
-                      JsPromptResponseAction action =
-                      await createPromptDialog(context, jsPromptRequest.message);
-                      return JsPromptResponse(
-                          handledByClient: true,
-                          action: action,
-                          value: _textFieldController.text);
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-
-  Future<JsAlertResponseAction> createAlertDialog(
-      BuildContext context, String message) async {
-    JsAlertResponseAction action;
-
-    await showDialog(
-      context: context,
-      builder: (BuildContext context) {
-        return AlertDialog(
-          content: Text(message),
-          actions: <Widget>[
-            FlatButton(
-              child: Text("Ok"),
-              key: Key("AlertButtonOk"),
-              onPressed: () {
-                action = JsAlertResponseAction.CONFIRM;
-                Navigator.of(context).pop();
-                setState(() {
-                  appBarTitle = "alert";
-                });
-              },
-            ),
-          ],
-        );
-      },
-    );
-
-    return action;
-  }
-
-  Future<JsConfirmResponseAction> createConfirmDialog(
-      BuildContext context, String message) async {
-    JsConfirmResponseAction action;
-
-    await showDialog(
-      context: context,
-      builder: (BuildContext context) {
-        return AlertDialog(
-          content: Text(message),
-          actions: <Widget>[
-            FlatButton(
-              child: Text("Cancel"),
-              key: Key("ConfirmButtonCancel"),
-              onPressed: () {
-                action = JsConfirmResponseAction.CANCEL;
-                Navigator.of(context).pop();
-              },
-            ),
-            FlatButton(
-              child: Text("Ok"),
-              key: Key("ConfirmButtonOk"),
-              onPressed: () {
-                action = JsConfirmResponseAction.CONFIRM;
-                Navigator.of(context).pop();
-              },
-            ),
-          ],
-        );
-      },
-    );
-
-    return action;
-  }
-
-  Future<JsPromptResponseAction> createPromptDialog(
-      BuildContext context, String message) async {
-    JsPromptResponseAction action;
-
-    await showDialog(
-      context: context,
-      builder: (BuildContext context) {
-        return AlertDialog(
-          title: Text(message),
-          content: TextField(
-            key: Key("PromptTextField"),
-            controller: _textFieldController,
-          ),
-          actions: <Widget>[
-            FlatButton(
-              child: Text("Cancel"),
-              key: Key("PromptButtonCancel"),
-              onPressed: () {
-                action = JsPromptResponseAction.CANCEL;
-                Navigator.of(context).pop();
-              },
-            ),
-            FlatButton(
-              child: Text("Ok"),
-              key: Key("PromptButtonOk"),
-              onPressed: () {
-                action = JsPromptResponseAction.CONFIRM;
-                Navigator.of(context).pop();
-              },
-            ),
-          ],
-        );
-      },
-    );
-
-    return action;
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_load_error_test.dart b/example/test_driver/in_app_webview_on_load_error_test.dart
deleted file mode 100755
index 7642d38f..00000000
--- a/example/test_driver/in_app_webview_on_load_error_test.dart
+++ /dev/null
@@ -1,59 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewOnLoadErrorTest extends WidgetTest {
-  final InAppWebViewOnLoadErrorTestState state = InAppWebViewOnLoadErrorTestState();
-
-  @override
-  InAppWebViewOnLoadErrorTestState createState() => state;
-}
-
-class InAppWebViewOnLoadErrorTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewOnLoadErrorTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://not-existing-domain.org/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadError: (InAppWebViewController controller, String url, int code, String message) async {
-                      setState(() {
-                        appBarTitle = code.toString();
-                      });
-                    }
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_load_http_error_test.dart b/example/test_driver/in_app_webview_on_load_http_error_test.dart
deleted file mode 100755
index 687b085f..00000000
--- a/example/test_driver/in_app_webview_on_load_http_error_test.dart
+++ /dev/null
@@ -1,59 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewOnLoadHttpErrorTest extends WidgetTest {
-  final InAppWebViewOnLoadHttpErrorTestState state = InAppWebViewOnLoadHttpErrorTestState();
-
-  @override
-  InAppWebViewOnLoadHttpErrorTestState createState() => state;
-}
-
-class InAppWebViewOnLoadHttpErrorTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewOnLoadHttpErrorTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://google.com/404",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadHttpError: (InAppWebViewController controller, String url, int statusCode, String description) async {
-                      setState(() {
-                        appBarTitle = statusCode.toString();
-                      });
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_load_resource_custom_scheme_test.dart b/example/test_driver/in_app_webview_on_load_resource_custom_scheme_test.dart
deleted file mode 100755
index dd48200a..00000000
--- a/example/test_driver/in_app_webview_on_load_resource_custom_scheme_test.dart
+++ /dev/null
@@ -1,69 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnLoadResourceCustomSchemeTest extends WidgetTest {
-  final InAppWebViewOnLoadResourceCustomSchemeTestState state = InAppWebViewOnLoadResourceCustomSchemeTestState();
-
-  @override
-  InAppWebViewOnLoadResourceCustomSchemeTestState createState() => state;
-}
-
-class InAppWebViewOnLoadResourceCustomSchemeTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnLoadResourceCustomSchemeTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_on_load_resource_custom_scheme_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                          clearCache: true,
-                          debuggingEnabled: true,
-                          resourceCustomSchemes: ["my-special-custom-scheme"]
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-
-                      webView.addJavaScriptHandler(handlerName: "imageLoaded", callback: (args) {
-                        setState(() {
-                          appBarTitle = "true";
-                        });
-                      });
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadResourceCustomScheme: (InAppWebViewController controller, String scheme, String url) async {
-                      if (scheme == "my-special-custom-scheme") {
-                        var bytes = await rootBundle.load("test_assets/" + url.replaceFirst("my-special-custom-scheme://", "", 0));
-                        var response = CustomSchemeResponse(data: bytes.buffer.asUint8List(), contentType: "image/svg+xml", contentEnconding: "utf-8");
-                        return response;
-                      }
-                      return null;
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_load_resource_test.dart b/example/test_driver/in_app_webview_on_load_resource_test.dart
deleted file mode 100755
index 272d86b8..00000000
--- a/example/test_driver/in_app_webview_on_load_resource_test.dart
+++ /dev/null
@@ -1,67 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnLoadResourceTest extends WidgetTest {
-  final InAppWebViewOnLoadResourceTestState state = InAppWebViewOnLoadResourceTestState();
-
-  @override
-  InAppWebViewOnLoadResourceTestState createState() => state;
-}
-
-class InAppWebViewOnLoadResourceTestState extends WidgetTestState {
-  List<String> resourceList = [
-    "https://getbootstrap.com/docs/4.3/dist/css/bootstrap.min.css",
-    "https://code.jquery.com/jquery-3.3.1.min.js",
-    "https://via.placeholder.com/100x50"
-  ];
-  int countResources = 0;
-  String appBarTitle = "InAppWebViewOnLoadResourceTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_on_load_resource_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                          clearCache: true,
-                          debuggingEnabled: true,
-                          useOnLoadResource: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadResource: (InAppWebViewController controller, LoadedResource response) {
-                      appBarTitle = (appBarTitle == "InAppWebViewOnLoadResourceTest") ? response.url : appBarTitle + " " + response.url;
-                      countResources++;
-                      if (countResources == resourceList.length) {
-                        setState(() {  });
-                      }
-                    }
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_navigation_state_change_test.dart b/example/test_driver/in_app_webview_on_navigation_state_change_test.dart
deleted file mode 100755
index cad07c7c..00000000
--- a/example/test_driver/in_app_webview_on_navigation_state_change_test.dart
+++ /dev/null
@@ -1,72 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'main_test.dart';
-import 'custom_widget_test.dart';
-
-class InAppWebViewOnNavigationStateChangeTest extends WidgetTest {
-  final InAppWebViewOnNavigationStateChangeTestState state = InAppWebViewOnNavigationStateChangeTestState();
-
-  @override
-  InAppWebViewOnNavigationStateChangeTestState createState() => state;
-}
-
-class InAppWebViewOnNavigationStateChangeTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewOnNavigationStateChangeTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      controller.evaluateJavascript(source: """
-var state = {}
-var title = ''
-var url = 'first-push';
-history.pushState(state, title, url);
-
-setTimeout(function() {
-    var url = 'second-push';
-    history.pushState(state, title, url);
-}, 100);
-""");
-                    },
-                    onUpdateVisitedHistory: (InAppWebViewController controller, String url, bool androidIsReload) async {
-                      if (url.endsWith("second-push")) {
-                        setState(() {
-                          appBarTitle += " " + url;
-                        });
-                      } else {
-                        appBarTitle = url;
-                      }
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_progress_changed_test.dart b/example/test_driver/in_app_webview_on_progress_changed_test.dart
deleted file mode 100755
index 80692469..00000000
--- a/example/test_driver/in_app_webview_on_progress_changed_test.dart
+++ /dev/null
@@ -1,61 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewOnProgressChangedTest extends WidgetTest {
-  final InAppWebViewOnProgressChangedTestState state = InAppWebViewOnProgressChangedTestState();
-
-  @override
-  InAppWebViewOnProgressChangedTestState createState() => state;
-}
-
-class InAppWebViewOnProgressChangedTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewOnProgressChangedTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-
-                    },
-                    onProgressChanged: (InAppWebViewController controller, int progress) {
-                      if (progress == 100) {
-                        setState(() {
-                          appBarTitle = "true";
-                        });
-                      }
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_received_http_auth_request_test.dart b/example/test_driver/in_app_webview_on_received_http_auth_request_test.dart
deleted file mode 100755
index 45296afc..00000000
--- a/example/test_driver/in_app_webview_on_received_http_auth_request_test.dart
+++ /dev/null
@@ -1,65 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-import '.env.dart';
-
-class InAppWebViewOnReceivedHttpAuthRequestTest extends WidgetTest {
-  final InAppWebViewOnReceivedHttpAuthRequestTestState state = InAppWebViewOnReceivedHttpAuthRequestTestState();
-
-  @override
-  InAppWebViewOnReceivedHttpAuthRequestTestState createState() => state;
-}
-
-class InAppWebViewOnReceivedHttpAuthRequestTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewOnReceivedHttpAuthRequestTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "http://${environment["NODE_SERVER_IP"]}:8081/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) async {
-                      String h1Content = await controller.evaluateJavascript(source: "document.body.querySelector('h1').textContent");
-                      setState(() {
-                        appBarTitle = h1Content;
-                      });
-                    },
-                    onReceivedHttpAuthRequest: (InAppWebViewController controller, HttpAuthChallenge challenge) async {
-                      return new HttpAuthResponse(
-                          username: "USERNAME",
-                          password: "PASSWORD",
-                          action: HttpAuthResponseAction.PROCEED,
-                          permanentPersistence: true);
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_safe_browsing_hit_test.dart b/example/test_driver/in_app_webview_on_safe_browsing_hit_test.dart
deleted file mode 100755
index f0b57fcb..00000000
--- a/example/test_driver/in_app_webview_on_safe_browsing_hit_test.dart
+++ /dev/null
@@ -1,68 +0,0 @@
-import 'dart:io';
-
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewOnSafeBrowsingHitTest extends WidgetTest {
-  final InAppWebViewOnSafeBrowsingHitTestState state = InAppWebViewOnSafeBrowsingHitTestState();
-
-  @override
-  InAppWebViewOnSafeBrowsingHitTestState createState() => state;
-}
-
-class InAppWebViewOnSafeBrowsingHitTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewOnSafeBrowsingHitTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: (Platform.isAndroid) ? "chrome://safe-browsing/match?type=malware" : "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            // if I set javaScriptEnabled to true, it will crash!
-                            javaScriptEnabled: false,
-                            clearCache: true,
-                            debuggingEnabled: true
-                        ),
-                        android: AndroidInAppWebViewOptions(
-                          safeBrowsingEnabled: true,
-                        ),
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                      if(Platform.isAndroid)
-                        controller.android.startSafeBrowsing();
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      setState(() {
-                        appBarTitle = url;
-                      });
-                    },
-                    androidOnSafeBrowsingHit: (InAppWebViewController controller, String url, SafeBrowsingThreat threatType) async {
-                      return SafeBrowsingResponse(report: true, action: SafeBrowsingResponseAction.PROCEED);
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_on_scroll_changed_test.dart b/example/test_driver/in_app_webview_on_scroll_changed_test.dart
deleted file mode 100755
index 4d4fa7d6..00000000
--- a/example/test_driver/in_app_webview_on_scroll_changed_test.dart
+++ /dev/null
@@ -1,63 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewOnScrollChangedTest extends WidgetTest {
-  final InAppWebViewOnScrollChangedTestState state = InAppWebViewOnScrollChangedTestState();
-
-  @override
-  InAppWebViewOnScrollChangedTestState createState() => state;
-}
-
-class InAppWebViewOnScrollChangedTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewOnScrollChangedTest";
-  bool scrolled = false;
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://flutter.dev/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      controller.scrollTo(x: 0, y: 500);
-                    },
-                    onScrollChanged: (InAppWebViewController controller, int x, int y) {
-                      if (!scrolled) {
-                        scrolled = true;
-                        setState(() {
-                          appBarTitle = "true";
-                        });
-                      }
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_should_override_url_loading_test.dart b/example/test_driver/in_app_webview_should_override_url_loading_test.dart
deleted file mode 100755
index e2df7813..00000000
--- a/example/test_driver/in_app_webview_should_override_url_loading_test.dart
+++ /dev/null
@@ -1,67 +0,0 @@
-import 'package:flutter/material.dart';
-import 'dart:io' show Platform;
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-
-class InAppWebViewShouldOverrideUrlLoadingTest extends WidgetTest {
-  final InAppWebViewShouldOverrideUrlLoadingTestState state = InAppWebViewShouldOverrideUrlLoadingTestState();
-
-  @override
-  InAppWebViewShouldOverrideUrlLoadingTestState createState() => state;
-}
-
-class InAppWebViewShouldOverrideUrlLoadingTestState extends WidgetTestState {
-  String appBarTitle = "InAppWebViewShouldOverrideUrlLoadingTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialFile: "test_assets/in_app_webview_initial_file_test.html",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true,
-                            useShouldOverrideUrlLoading: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) {
-                      if (url == "https://flutter.dev/") {
-                        setState(() {
-                          appBarTitle = url;
-                        });
-                      } else {
-                        controller.evaluateJavascript(source: "document.querySelector('#link').click();");
-                      }
-                    },
-                    shouldOverrideUrlLoading: (InAppWebViewController controller, ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest) async {
-                      if (Platform.isAndroid || shouldOverrideUrlLoadingRequest.iosWKNavigationType == IOSWKNavigationType.LINK_ACTIVATED) {
-                        await controller.loadUrl(url: "https://flutter.dev/");
-                        return ShouldOverrideUrlLoadingAction.CANCEL;
-                      }
-                      return ShouldOverrideUrlLoadingAction.ALLOW;
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/in_app_webview_ssl_request_test.dart b/example/test_driver/in_app_webview_ssl_request_test.dart
deleted file mode 100755
index a73de007..00000000
--- a/example/test_driver/in_app_webview_ssl_request_test.dart
+++ /dev/null
@@ -1,68 +0,0 @@
-import 'package:flutter/material.dart';
-
-import 'package:flutter_inappwebview/flutter_inappwebview.dart';
-
-import 'custom_widget_test.dart';
-import 'main_test.dart';
-import '.env.dart';
-
-class InAppWebViewSslRequestTest extends WidgetTest {
-  final InAppWebViewSslRequestTestState state = InAppWebViewSslRequestTestState();
-
-  @override
-  InAppWebViewSslRequestTestState createState() => state;
-}
-
-class InAppWebViewSslRequestTestState extends WidgetTestState {
-
-  String appBarTitle = "InAppWebViewSslRequestTest";
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-        key: this.scaffoldKey,
-        appBar: myAppBar(state: this, title: appBarTitle),
-        drawer: myDrawer(context: context),
-        body: Container(
-            child: Column(children: <Widget>[
-              Expanded(
-                child: Container(
-                  child: InAppWebView(
-                    initialUrl: "https://${environment["NODE_SERVER_IP"]}:4433/",
-                    initialHeaders: {},
-                    initialOptions: InAppWebViewGroupOptions(
-                        crossPlatform: InAppWebViewOptions(
-                            clearCache: true,
-                            debuggingEnabled: true
-                        )
-                    ),
-                    onWebViewCreated: (InAppWebViewController controller) {
-                      webView = controller;
-                    },
-                    onLoadStart: (InAppWebViewController controller, String url) {
-
-                    },
-                    onLoadStop: (InAppWebViewController controller, String url) async {
-                      String h1Content = await controller.evaluateJavascript(source: "document.body.querySelector('h1').textContent");
-                      setState(() {
-                        appBarTitle = h1Content;
-                      });
-                    },
-                    onReceivedServerTrustAuthRequest: (InAppWebViewController controller, ServerTrustChallenge challenge) async {
-                      return new ServerTrustAuthResponse(action: ServerTrustAuthResponseAction.PROCEED);
-                    },
-                    onReceivedClientCertRequest: (InAppWebViewController controller, ClientCertChallenge challenge) async {
-                      return new ClientCertResponse(
-                          certificatePath: "test_assets/certificate.pfx",
-                          certificatePassword: "",
-                          androidKeyStoreType: "PKCS12",
-                          action: ClientCertResponseAction.PROCEED);
-                    },
-                  ),
-                ),
-              ),
-            ])
-        )
-    );
-  }
-}
diff --git a/example/test_driver/integration_test.dart b/example/test_driver/integration_test.dart
new file mode 100644
index 00000000..61c01a8c
--- /dev/null
+++ b/example/test_driver/integration_test.dart
@@ -0,0 +1,15 @@
+// @dart = 2.9
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+import 'package:flutter_driver/flutter_driver.dart';
+
+Future<void> main() async {
+  final FlutterDriver driver = await FlutterDriver.connect();
+  final String data =
+  await driver.requestData(null, timeout: const Duration(minutes: 1));
+  await driver.close();
+  final Map<String, dynamic> result = jsonDecode(data);
+  exit(result['result'] == 'true' ? 0 : 1);
+}
\ No newline at end of file
diff --git a/example/test_driver/main_test.dart b/example/test_driver/main_test.dart
deleted file mode 100755
index db78a779..00000000
--- a/example/test_driver/main_test.dart
+++ /dev/null
@@ -1,153 +0,0 @@
-import 'dart:async';
-
-import 'package:flutter/material.dart';
-
-import 'custom_widget_test.dart';
-import 'in_app_webview_ajax_test.dart';
-import 'in_app_webview_content_blocker_test.dart';
-import 'in_app_webview_cookie_manager_test.dart';
-import 'in_app_webview_fetch_test.dart';
-import 'in_app_webview_http_auth_credential_database_test.dart';
-import 'in_app_webview_initial_data_test.dart';
-import 'in_app_webview_initial_file_test.dart';
-import 'in_app_webview_initial_url_test.dart';
-import 'in_app_webview_javascript_handler_test.dart';
-import 'in_app_webview_on_console_message_test.dart';
-import 'in_app_webview_on_download_start_test.dart';
-import 'in_app_webview_on_find_result_received_test.dart';
-import 'in_app_webview_on_js_dialog_test.dart';
-import 'in_app_webview_on_load_error_test.dart';
-import 'in_app_webview_on_load_http_error_test.dart';
-import 'in_app_webview_on_load_resource_custom_scheme_test.dart';
-import 'in_app_webview_on_load_resource_test.dart';
-import 'in_app_webview_on_navigation_state_change_test.dart';
-import 'in_app_webview_on_progress_changed_test.dart';
-import 'in_app_webview_on_received_http_auth_request_test.dart';
-import 'in_app_webview_on_safe_browsing_hit_test.dart';
-import 'in_app_webview_on_scroll_changed_test.dart';
-import 'in_app_webview_on_create_window_test.dart';
-import 'in_app_webview_should_override_url_loading_test.dart';
-import 'in_app_webview_ssl_request_test.dart';
-
-Map<String, WidgetBuilder> getTestRoutes({@required BuildContext context}) {
-  var routes = {
-    '/': (context) => InAppWebViewInitialUrlTest(),
-    '/InAppWebViewInitialFileTest': (context) => InAppWebViewInitialFileTest(),
-    '/InAppWebViewInitialDataTest': (context) => InAppWebViewInitialDataTest(),
-    '/InAppWebViewOnProgressChangedTest': (context) => InAppWebViewOnProgressChangedTest(),
-    '/InAppWebViewOnScrollChangedTest': (context) => InAppWebViewOnScrollChangedTest(),
-    '/InAppWebViewOnLoadResourceTest': (context) => InAppWebViewOnLoadResourceTest(),
-    '/InAppWebViewJavaScriptHandlerTest': (context) => InAppWebViewJavaScriptHandlerTest(),
-    '/InAppWebViewAjaxTest': (context) => InAppWebViewAjaxTest(),
-    '/InAppWebViewFetchTest': (context) => InAppWebViewFetchTest(),
-    '/InAppWebViewOnLoadResourceCustomSchemeTest': (context) => InAppWebViewOnLoadResourceCustomSchemeTest(),
-    '/InAppWebViewShouldOverrideUrlLoadingTest': (context) => InAppWebViewShouldOverrideUrlLoadingTest(),
-    '/InAppWebViewOnConsoleMessageTest': (context) => InAppWebViewOnConsoleMessageTest(),
-    '/InAppWebViewOnDownloadStartTest': (context) => InAppWebViewOnDownloadStartTest(),
-    '/InAppWebViewOnCreateWindowTest': (context) => InAppWebViewOnCreateWindowTest(),
-    '/InAppWebViewOnJsDialogTest': (context) => InAppWebViewOnJsDialogTest(),
-    '/InAppWebViewOnSafeBrowsingHitTest': (context) => InAppWebViewOnSafeBrowsingHitTest(),
-    '/InAppWebViewOnReceivedHttpAuthRequestTest': (context) => InAppWebViewOnReceivedHttpAuthRequestTest(),
-    '/InAppWebViewSslRequestTest': (context) => InAppWebViewSslRequestTest(),
-    '/InAppWebViewOnFindResultReceivedTest': (context) => InAppWebViewOnFindResultReceivedTest(),
-    '/InAppWebViewOnNavigationStateChangeTest': (context) => InAppWebViewOnNavigationStateChangeTest(),
-    '/InAppWebViewOnLoadErrorTest': (context) => InAppWebViewOnLoadErrorTest(),
-    '/InAppWebViewOnLoadHttpErrorTest': (context) => InAppWebViewOnLoadHttpErrorTest(),
-    '/InAppWebViewCookieManagerTest': (context) => InAppWebViewCookieManagerTest(),
-    '/InAppWebViewHttpAuthCredentialDatabaseTest': (context) => InAppWebViewHttpAuthCredentialDatabaseTest(),
-    '/InAppWebViewContentBlockerTest': (context) => InAppWebViewContentBlockerTest(),
-  };
-  return routes;
-}
-
-AppBar myAppBar({@required WidgetTestState state, @required String title}) {
-
-  return AppBar(
-    title: Text(
-      title,
-      key: Key("AppBarTitle")
-    ),
-    actions: <Widget>[
-      IconButton(
-        icon: Icon(Icons.menu),
-        key: Key("SideMenu"),
-        onPressed: () {
-          state.scaffoldKey.currentState.openDrawer();
-        },
-      ),
-      IconButton(
-        icon: Icon(Icons.refresh),
-        onPressed: () {
-          if (state.webView != null)
-            state.webView.reload();
-        },
-      ),
-    ],
-  );
-}
-
-Drawer myDrawer({@required context}) {
-  var routes = getTestRoutes(context: context);
-  List<Widget> listTiles = [
-    DrawerHeader(
-      child: Text('Tests'),
-      decoration: BoxDecoration(
-        color: Colors.blue,
-      ),
-    )
-  ];
-  for (String k in routes.keys) {
-    var title = "";
-    if (k == "/") {
-      title = "InAppWebViewInitialUrlTest";
-    } else {
-      title = k.substring(1);
-    }
-    listTiles.add(ListTile(
-      title: Text(title),
-      key: Key(title),
-      onTap: () {
-        Navigator.pushReplacementNamed(context, k);
-      },
-    ));
-  }
-  return Drawer(
-    child: ListView(
-      key: Key("ListTiles"),
-      padding: EdgeInsets.zero,
-      children: listTiles,
-    ),
-  );
-}
-
-Future main() async {
-  WidgetsFlutterBinding.ensureInitialized();
-  runApp(new MyApp());
-}
-
-class MyApp extends StatefulWidget {
-  @override
-  _MyAppState createState() => new _MyAppState();
-}
-
-class _MyAppState extends State<MyApp> {
-
-  @override
-  void initState() {
-    super.initState();
-  }
-
-  @override
-  void dispose() {
-    super.dispose();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return MaterialApp(
-      title: 'flutter_inappbrowser tests',
-      initialRoute: '/',
-      routes: getTestRoutes(context: context)
-    );
-  }
-}
\ No newline at end of file
diff --git a/flutter_inappwebview.iml b/flutter_inappwebview.iml
index c8905c93..3acc9934 100755
--- a/flutter_inappwebview.iml
+++ b/flutter_inappwebview.iml
@@ -14,6 +14,12 @@
       <excludeFolder url="file://$MODULE_DIR$/example/flutter_plugin/.dart_tool" />
       <excludeFolder url="file://$MODULE_DIR$/example/flutter_plugin/.pub" />
       <excludeFolder url="file://$MODULE_DIR$/example/flutter_plugin/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_downloader/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_downloader/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_downloader/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_downloader/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_downloader/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_downloader/example/build" />
       <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_inappbrowser/.dart_tool" />
       <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_inappbrowser/.pub" />
       <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_inappbrowser/build" />
@@ -27,6 +33,33 @@
       <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_inappwebview/example/.pub" />
       <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_inappwebview/example/build" />
       <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/flutter_inappwebview/example/ios/Flutter/App.framework/flutter_assets/packages" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/integration_test_macos/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/integration_test_macos/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/integration_test/integration_test_macos/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/path_provider/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/path_provider/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/path_provider/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/path_provider/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/path_provider/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/path_provider/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/permission_handler/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/permission_handler/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/permission_handler/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/permission_handler/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/permission_handler/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/permission_handler/example/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/url_launcher/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/url_launcher/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/url_launcher/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/url_launcher/example/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/url_launcher/example/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/example/ios/.symlinks/plugins/url_launcher/example/build" />
       <excludeFolder url="file://$MODULE_DIR$/example/ios/Flutter/App.framework/flutter_assets/packages" />
       <excludeFolder url="file://$MODULE_DIR$/flutter_inappbrowser_tests/.dart_tool" />
       <excludeFolder url="file://$MODULE_DIR$/flutter_inappbrowser_tests/.pub" />
diff --git a/ios/Classes/InAppWebView.swift b/ios/Classes/InAppWebView.swift
index 264c6fd4..e6f230ee 100755
--- a/ios/Classes/InAppWebView.swift
+++ b/ios/Classes/InAppWebView.swift
@@ -1153,7 +1153,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate, WKNavi
             scrollView.maximumZoomScale = CGFloat(options.maximumZoomScale)
             scrollView.minimumZoomScale = CGFloat(options.minimumZoomScale)
             
-            // options.debuggingEnabled is always enabled for iOS,
+            // debugging is always enabled for iOS,
             // there isn't any option to set about it such as on Android.
             
             if options.clearCache {
@@ -2498,6 +2498,9 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate, WKNavi
                 }
                 if !handledByClient, InAppWebView.windowWebViews[windowId] != nil {
                     InAppWebView.windowWebViews.removeValue(forKey: windowId)
+                    if let url = navigationAction.request.url {
+                        self.loadUrl(url: url, headers: nil)
+                    }
                 }
             }
         })
diff --git a/ios/Classes/InAppWebViewOptions.swift b/ios/Classes/InAppWebViewOptions.swift
index 7668370a..0e33e74a 100755
--- a/ios/Classes/InAppWebViewOptions.swift
+++ b/ios/Classes/InAppWebViewOptions.swift
@@ -18,7 +18,6 @@ public class InAppWebViewOptions: Options<InAppWebView> {
     var userAgent = ""
     var applicationNameForUserAgent = ""
     var javaScriptEnabled = true
-    var debuggingEnabled = true
     var javaScriptCanOpenWindowsAutomatically = false
     var mediaPlaybackRequiresUserGesture = true
     var verticalScrollBarEnabled = true
diff --git a/lib/src/X509Certificate/asn1_decoder.dart b/lib/src/X509Certificate/asn1_decoder.dart
index 94a85305..abe06d1c 100644
--- a/lib/src/X509Certificate/asn1_decoder.dart
+++ b/lib/src/X509Certificate/asn1_decoder.dart
@@ -1,17 +1,16 @@
 import 'dart:convert';
 import 'dart:typed_data';
 
-import 'package:flutter/foundation.dart';
 import 'asn1_identifier.dart';
 import 'asn1_object.dart';
 
 class ASN1DERDecoder {
-  static List<ASN1Object> decode({@required List<int> data}) {
+  static List<ASN1Object> decode({required List<int> data}) {
     var iterator = data.iterator;
     return parse(iterator: iterator);
   }
 
-  static List<ASN1Object> parse({@required Iterator<int> iterator}) {
+  static List<ASN1Object> parse({required Iterator<int> iterator}) {
     var result = <ASN1Object>[];
 
     while (iterator.moveNext()) {
@@ -20,7 +19,7 @@ class ASN1DERDecoder {
       var asn1obj = ASN1Object();
       asn1obj.identifier = ASN1Identifier(nextValue);
 
-      if (asn1obj.identifier.isConstructed()) {
+      if (asn1obj.identifier!.isConstructed()) {
         var contentData = loadSubContent(iterator: iterator);
 
         if (contentData.isEmpty) {
@@ -34,18 +33,20 @@ class ASN1DERDecoder {
 
         asn1obj.encoded = Uint8List.fromList(contentData);
 
-        for (var item in asn1obj.sub) {
-          item.parent = asn1obj;
+        if (asn1obj.sub != null) {
+          for (var item in asn1obj.sub!) {
+            item.parent = asn1obj;
+          }
         }
       } else {
-        if (asn1obj.identifier.typeClass() == ASN1IdentifierClass.UNIVERSAL) {
+        if (asn1obj.identifier!.typeClass() == ASN1IdentifierClass.UNIVERSAL) {
           var contentData = loadSubContent(iterator: iterator);
 
           asn1obj.encoded = Uint8List.fromList(contentData);
 
           // decode the content data with come more convenient format
 
-          var tagNumber = asn1obj.identifier.tagNumber();
+          var tagNumber = asn1obj.identifier!.tagNumber();
 
           if (tagNumber == ASN1IdentifierTagNumber.END_OF_CONTENT) {
             return result;
@@ -130,9 +131,12 @@ class ASN1DERDecoder {
     return result;
   }
 
-  static BigInt getContentLength({@required Iterator<int> iterator}) {
+  static BigInt getContentLength({required Iterator<int> iterator}) {
     if (iterator.moveNext()) {
-      var first = iterator.current;
+      int? first;
+      try {
+        first = iterator.current;
+      } catch (e) {}
       if (first != null) {
         if ((first & 0x80) != 0) {
           // long
@@ -141,7 +145,10 @@ class ASN1DERDecoder {
           var data = <int>[];
           for (var i = 0; i < octetsToRead; i++) {
             if (iterator.moveNext()) {
-              var n = iterator.current;
+              int? n;
+              try {
+                n = iterator.current;
+              } catch (e) {}
               if (n != null) {
                 data.add(n);
               }
@@ -158,7 +165,7 @@ class ASN1DERDecoder {
     return BigInt.from(0);
   }
 
-  static List<int> loadSubContent({@required Iterator<int> iterator}) {
+  static List<int> loadSubContent({required Iterator<int> iterator}) {
     var len = getContentLength(iterator: iterator);
     int int64MaxValue = double.maxFinite.toInt();
 
@@ -170,7 +177,10 @@ class ASN1DERDecoder {
 
     for (var i = 0; i < len.toInt(); i++) {
       if (iterator.moveNext()) {
-        var n = iterator.current;
+        int? n;
+        try {
+          n = iterator.current;
+        } catch (e) {}
         if (n != null) {
           byteArray.add(n);
         }
@@ -183,7 +193,7 @@ class ASN1DERDecoder {
   }
 
   /// Decode DER OID bytes to String with dot notation
-  static String decodeOid({@required List<int> contentData}) {
+  static String decodeOid({required List<int> contentData}) {
     if (contentData.isEmpty) {
       return "";
     }
@@ -211,7 +221,7 @@ class ASN1DERDecoder {
   ///dates past 2049. Parsing that structure hasn't been implemented yet.
   ///
   ///[contentData] the UTCTime value to convert.
-  static DateTime utcTimeToDate({@required List<int> contentData}) {
+  static DateTime? utcTimeToDate({required List<int> contentData}) {
     /* The following formats can be used:
       YYMMDDhhmmZ
       YYMMDDhhmm+hh'mm'
@@ -231,7 +241,7 @@ class ASN1DERDecoder {
       hh' is the absolute value of the offset from GMT in hours
       mm' is the absolute value of the offset from GMT in minutes */
 
-    String utc;
+    String? utc;
     try {
       utc = utf8.decode(contentData);
     } catch (e) {}
@@ -250,8 +260,8 @@ class ASN1DERDecoder {
     var mm = int.parse(utc.substring(8, 10), radix: 10);
     var ss = 0;
 
-    int end;
-    String c;
+    int? end;
+    String? c;
     // not just YYMMDDhhmmZ
     if (utc.length > 11) {
       // get character after minutes
@@ -298,7 +308,7 @@ class ASN1DERDecoder {
   ///Converts a GeneralizedTime value to a date.
   ///
   ///[contentData] the GeneralizedTime value to convert.
-  static DateTime generalizedTimeToDate({@required List<int> contentData}) {
+  static DateTime? generalizedTimeToDate({required List<int> contentData}) {
     /* The following formats can be used:
       YYYYMMDDHHMMSS
       YYYYMMDDHHMMSS.fff
@@ -321,7 +331,7 @@ class ASN1DERDecoder {
       hh' is the absolute value of the offset from GMT in hours
       mm' is the absolute value of the offset from GMT in minutes */
 
-    String gentime;
+    String? gentime;
     try {
       gentime = utf8.decode(contentData);
     } catch (e) {}
@@ -385,7 +395,7 @@ class ASN1DERDecoder {
   }
 }
 
-BigInt toIntValue(List<int> data) {
+BigInt? toIntValue(List<int> data) {
   if (data.length > 8) {
     return null;
   }
diff --git a/lib/src/X509Certificate/asn1_distinguished_names.dart b/lib/src/X509Certificate/asn1_distinguished_names.dart
index 3340693c..98035db7 100644
--- a/lib/src/X509Certificate/asn1_distinguished_names.dart
+++ b/lib/src/X509Certificate/asn1_distinguished_names.dart
@@ -19,10 +19,15 @@ class ASN1DistinguishedNames {
     ASN1DistinguishedNames.EMAIL,
   ].toSet();
 
-  static ASN1DistinguishedNames fromValue(String oid) {
-    if (oid != null)
-      return ASN1DistinguishedNames.values
-          .firstWhere((element) => element.oid() == oid, orElse: () => null);
+  static ASN1DistinguishedNames? fromValue(String? oid) {
+    if (oid != null) {
+      try {
+        return ASN1DistinguishedNames.values
+            .firstWhere((element) => element.oid() == oid);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
diff --git a/lib/src/X509Certificate/asn1_identifier.dart b/lib/src/X509Certificate/asn1_identifier.dart
index f2086f1f..0512b785 100644
--- a/lib/src/X509Certificate/asn1_identifier.dart
+++ b/lib/src/X509Certificate/asn1_identifier.dart
@@ -10,11 +10,15 @@ class ASN1IdentifierClass {
     ASN1IdentifierClass.PRIVATE,
   ].toSet();
 
-  static ASN1IdentifierClass fromValue(int value) {
-    if (value != null)
-      return ASN1IdentifierClass.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static ASN1IdentifierClass? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return ASN1IdentifierClass.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -83,11 +87,15 @@ class ASN1IdentifierTagNumber {
     ASN1IdentifierTagNumber.BMP_STRING,
   ].toSet();
 
-  static ASN1IdentifierTagNumber fromValue(int value) {
-    if (value != null)
-      return ASN1IdentifierTagNumber.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static ASN1IdentifierTagNumber? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return ASN1IdentifierTagNumber.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
diff --git a/lib/src/X509Certificate/asn1_object.dart b/lib/src/X509Certificate/asn1_object.dart
index e46232d2..7fc73d08 100644
--- a/lib/src/X509Certificate/asn1_object.dart
+++ b/lib/src/X509Certificate/asn1_object.dart
@@ -7,34 +7,34 @@ import 'oid.dart';
 
 class ASN1Object {
   /// This property contains the DER encoded object
-  Uint8List encoded;
+  Uint8List? encoded;
 
   /// This property contains the decoded Swift object whenever is possible
   dynamic value;
 
-  ASN1Identifier identifier;
+  ASN1Identifier? identifier;
 
-  List<ASN1Object> sub;
+  List<ASN1Object>? sub;
 
-  ASN1Object parent;
+  ASN1Object? parent;
 
-  ASN1Object subAtIndex(int index) {
-    if (sub != null && index >= 0 && index < sub.length) {
-      return sub[index];
+  ASN1Object? subAtIndex(int index) {
+    if (sub != null && index >= 0 && index < sub!.length) {
+      return sub![index];
     }
     return null;
   }
 
-  ASN1Object firstSub() {
+  ASN1Object? firstSub() {
     if (subCount() > 0) {
-      return sub.first;
+      return sub!.first;
     }
     return null;
   }
 
-  ASN1Object lastSub() {
+  ASN1Object? lastSub() {
     if (subCount() > 0) {
-      return sub.last;
+      return sub!.last;
     }
     return null;
   }
@@ -43,7 +43,7 @@ class ASN1Object {
     return sub?.length ?? 0;
   }
 
-  ASN1Object findOid({OID oid, String oidValue}) {
+  ASN1Object? findOid({OID? oid, String? oidValue}) {
     oidValue = oid != null ? oid.toValue() : oidValue;
     for (var child in (sub ?? <ASN1Object>[])) {
       if (child.identifier?.tagNumber() ==
@@ -67,7 +67,7 @@ class ASN1Object {
 
   String printAsn1({insets = ""}) {
     var output = insets;
-    output += identifier?.description?.toUpperCase() ?? "";
+    output += identifier?.description.toUpperCase() ?? "";
     output += (value != null ? ": $value" : "");
     if (identifier?.typeClass() == ASN1IdentifierClass.UNIVERSAL &&
         identifier?.tagNumber() == ASN1IdentifierTagNumber.OBJECT_IDENTIFIER) {
@@ -76,12 +76,12 @@ class ASN1Object {
         output += " ($descr)";
       }
     }
-    output += sub != null && sub.length > 0 ? " {" : "";
+    output += sub != null && sub!.length > 0 ? " {" : "";
     output += "\n";
     for (var item in (sub ?? <ASN1Object>[])) {
       output += item.printAsn1(insets: insets + "    ");
     }
-    output += sub != null && sub.length > 0 ? "}\n" : "";
+    output += sub != null && sub!.length > 0 ? "}\n" : "";
     return output;
   }
 
@@ -90,9 +90,9 @@ class ASN1Object {
     return description;
   }
 
-  ASN1Object atIndex(X509BlockPosition x509blockPosition) {
-    if (sub != null && x509blockPosition.index < sub.length) {
-      return sub[x509blockPosition.index];
+  ASN1Object? atIndex(X509BlockPosition x509blockPosition) {
+    if (sub != null && x509blockPosition.index < sub!.length) {
+      return sub![x509blockPosition.index];
     }
     return null;
   }
diff --git a/lib/src/X509Certificate/key_usage.dart b/lib/src/X509Certificate/key_usage.dart
index 20c8b569..871f034e 100644
--- a/lib/src/X509Certificate/key_usage.dart
+++ b/lib/src/X509Certificate/key_usage.dart
@@ -15,14 +15,20 @@ class KeyUsage {
     KeyUsage.decipherOnly,
   ].toSet();
 
-  static KeyUsage fromIndex(int value) {
-    return KeyUsage.values.firstWhere((element) => element.toValue() == value,
-        orElse: () => null);
+  static KeyUsage? fromIndex(int? value) {
+    if (value != null) {
+      try {
+        return KeyUsage.values.firstWhere((element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
+    return null;
   }
 
   int toValue() => _value;
 
-  String name() => _KeyUsageMapName[this._value];
+  String name() => _KeyUsageMapName.containsKey(this._value) ? _KeyUsageMapName[this._value]! : "";
 
   @override
   String toString() => "($_value, ${name()})";
diff --git a/lib/src/X509Certificate/oid.dart b/lib/src/X509Certificate/oid.dart
index 5288559e..52d6427c 100644
--- a/lib/src/X509Certificate/oid.dart
+++ b/lib/src/X509Certificate/oid.dart
@@ -102,14 +102,20 @@ class OID {
     OID.timeStamping,
   ].toSet();
 
-  static OID fromValue(String value) {
-    return OID.values.firstWhere((element) => element.toValue() == value,
-        orElse: () => null);
+  static OID? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return OID.values.firstWhere((element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
+    return null;
   }
 
   String toValue() => _value;
 
-  String name() => _oidMapName[this._value];
+  String name() => _oidMapName.containsKey(this._value) ? _oidMapName[this._value]! : "";
 
   @override
   String toString() => "($_value, ${name()})";
diff --git a/lib/src/X509Certificate/x509_certificate.dart b/lib/src/X509Certificate/x509_certificate.dart
index e0bbd8db..4375e064 100644
--- a/lib/src/X509Certificate/x509_certificate.dart
+++ b/lib/src/X509Certificate/x509_certificate.dart
@@ -1,7 +1,6 @@
 import 'dart:convert';
 import 'dart:typed_data';
 
-import 'package:flutter/foundation.dart';
 import 'asn1_decoder.dart';
 import 'asn1_object.dart';
 import 'oid.dart';
@@ -13,19 +12,19 @@ import 'asn1_distinguished_names.dart';
 ///Class that represents a X.509 certificate.
 ///This provides a standard way to access all the attributes of an X.509 certificate.
 class X509Certificate {
-  List<ASN1Object> asn1;
-  ASN1Object block1;
+  List<ASN1Object>? asn1;
+  ASN1Object? block1;
 
   ///Returns the encoded form of this certificate. It is
   ///assumed that each certificate type would have only a single
   ///form of encoding; for example, X.509 certificates would
   ///be encoded as ASN.1 DER.
-  Uint8List encoded;
+  Uint8List? encoded;
 
   static const beginPemBlock = "-----BEGIN CERTIFICATE-----";
   static const endPemBlock = "-----END CERTIFICATE-----";
 
-  X509Certificate({ASN1Object asn1}) {
+  X509Certificate({ASN1Object? asn1}) {
     if (asn1 != null) {
       var block1 = asn1.subAtIndex(0);
       if (block1 == null) {
@@ -34,7 +33,7 @@ class X509Certificate {
     }
   }
 
-  static X509Certificate fromData({@required Uint8List data}) {
+  static X509Certificate fromData({required Uint8List data}) {
     var decoded = utf8.decode(data, allowMalformed: true);
     if (decoded.contains(X509Certificate.beginPemBlock)) {
       return X509Certificate.fromPemData(pem: data);
@@ -43,10 +42,10 @@ class X509Certificate {
     }
   }
 
-  static X509Certificate fromDerData({@required Uint8List der}) {
+  static X509Certificate fromDerData({required Uint8List der}) {
     var asn1 = ASN1DERDecoder.decode(data: der.toList(growable: true));
     if (asn1.length > 0) {
-      var block1 = asn1.first?.subAtIndex(0);
+      var block1 = asn1.first.subAtIndex(0);
       if (block1 != null) {
         var certificate = X509Certificate();
         certificate.asn1 = asn1;
@@ -58,7 +57,7 @@ class X509Certificate {
     throw ASN1ParseError();
   }
 
-  static X509Certificate fromPemData({@required Uint8List pem}) {
+  static X509Certificate fromPemData({required Uint8List pem}) {
     var derData = X509Certificate.decodeToDER(pemData: pem);
     if (derData == null) {
       throw ASN1ParseError();
@@ -67,9 +66,9 @@ class X509Certificate {
   }
 
   ///Read possible PEM encoding
-  static Uint8List decodeToDER({@required pemData}) {
+  static Uint8List? decodeToDER({required pemData}) {
     var pem = String.fromCharCodes(pemData);
-    if (pem != null && pem.contains(X509Certificate.beginPemBlock)) {
+    if (pem.contains(X509Certificate.beginPemBlock)) {
       var lines = pem.split("\n");
       var base64buffer = "";
       var certLine = false;
@@ -85,7 +84,7 @@ class X509Certificate {
         }
       }
 
-      Uint8List derDataDecoded;
+      Uint8List? derDataDecoded;
       try {
         derDataDecoded = Uint8List.fromList(utf8.encode(base64buffer));
       } catch (e) {}
@@ -97,26 +96,28 @@ class X509Certificate {
   }
 
   String get description =>
-      asn1.fold("", (value, element) => value + element.description + "\n");
+      asn1?.fold("", (value, element) => (value ?? '') + element.description + '\n') ?? '';
 
   ///Checks that the given date is within the certificate's validity period.
-  bool checkValidity({DateTime date}) {
+  bool checkValidity({DateTime? date}) {
     if (date == null) {
       date = DateTime.now();
     }
     if (notBefore != null && notAfter != null) {
-      return date.isAfter(notBefore) && date.isBefore(notAfter);
+      return date.isAfter(notBefore!) && date.isBefore(notAfter!);
     }
     return false;
   }
 
   ///Gets the version (version number) value from the certificate.
-  int get version {
-    var v = firstLeafValue(block: block1) as List<int>;
-    if (v != null) {
-      var index = toIntValue(v);
-      if (index != null) {
-        return index.toInt() + 1;
+  int? get version {
+    if (block1 != null) {
+      var v = firstLeafValue(block: block1!) as List<int>?;
+      if (v != null) {
+        var index = toIntValue(v);
+        if (index != null) {
+          return index.toInt() + 1;
+        }
       }
     }
     return null;
@@ -124,11 +125,11 @@ class X509Certificate {
 
   ///Gets the serialNumber value from the certificate.
   List<int> get serialNumber =>
-      block1.atIndex(X509BlockPosition.serialNumber)?.value as List<int>;
+      block1?.atIndex(X509BlockPosition.serialNumber)?.value as List<int>;
 
   ///Returns the issuer (issuer distinguished name) value from the certificate as a String.
-  String get issuerDistinguishedName {
-    var issuerBlock = block1.atIndex(X509BlockPosition.issuer);
+  String? get issuerDistinguishedName {
+    var issuerBlock = block1?.atIndex(X509BlockPosition.issuer);
     if (issuerBlock != null) {
       return blockDistinguishedName(block: issuerBlock);
     }
@@ -137,10 +138,10 @@ class X509Certificate {
 
   List<String> get issuerOIDs {
     var result = <String>[];
-    var issuerBlock = block1.atIndex(X509BlockPosition.issuer);
+    var issuerBlock = block1?.atIndex(X509BlockPosition.issuer);
     if (issuerBlock != null) {
       for (var sub in (issuerBlock.sub ?? <ASN1Object>[])) {
-        var value = firstLeafValue(block: sub) as String;
+        var value = firstLeafValue(block: sub) as String?;
         if (value != null) {
           result.add(value);
         }
@@ -149,12 +150,12 @@ class X509Certificate {
     return result;
   }
 
-  String issuer({String oid, ASN1DistinguishedNames dn}) {
+  String? issuer({String? oid, ASN1DistinguishedNames? dn}) {
     if (oid == null && dn != null) {
       oid = dn.oid();
     }
     if (oid != null) {
-      var issuerBlock = block1.atIndex(X509BlockPosition.issuer);
+      var issuerBlock = block1?.atIndex(X509BlockPosition.issuer);
       if (issuerBlock != null) {
         var oidBlock = issuerBlock.findOid(oidValue: oid);
         if (oidBlock != null) {
@@ -171,8 +172,8 @@ class X509Certificate {
   }
 
   ///Returns the subject (subject distinguished name) value from the certificate as a String.
-  String get subjectDistinguishedName {
-    var subjectBlock = block1.atIndex(X509BlockPosition.subject);
+  String? get subjectDistinguishedName {
+    var subjectBlock = block1?.atIndex(X509BlockPosition.subject);
     if (subjectBlock != null) {
       return blockDistinguishedName(block: subjectBlock);
     }
@@ -181,10 +182,10 @@ class X509Certificate {
 
   List<String> get subjectOIDs {
     var result = <String>[];
-    var subjectBlock = block1.atIndex(X509BlockPosition.subject);
+    var subjectBlock = block1?.atIndex(X509BlockPosition.subject);
     if (subjectBlock != null) {
       for (var sub in (subjectBlock.sub ?? <ASN1Object>[])) {
-        var value = firstLeafValue(block: sub) as String;
+        var value = firstLeafValue(block: sub) as String?;
         if (value != null) {
           result.add(value);
         }
@@ -193,12 +194,12 @@ class X509Certificate {
     return result;
   }
 
-  String subject({String oid, ASN1DistinguishedNames dn}) {
+  String? subject({String? oid, ASN1DistinguishedNames? dn}) {
     if (oid == null && dn != null) {
       oid = dn.oid();
     }
     if (oid != null) {
-      var subjectBlock = block1.atIndex(X509BlockPosition.subject);
+      var subjectBlock = block1?.atIndex(X509BlockPosition.subject);
       if (subjectBlock != null) {
         var oidBlock = subjectBlock.findOid(oidValue: oid);
         if (oidBlock != null) {
@@ -215,30 +216,29 @@ class X509Certificate {
   }
 
   ///Gets the notBefore date from the validity period of the certificate.
-  DateTime get notBefore =>
-      block1.atIndex(X509BlockPosition.dateValidity)?.subAtIndex(0)?.value
-          as DateTime;
+  DateTime? get notBefore =>
+      block1?.atIndex(X509BlockPosition.dateValidity)?.subAtIndex(0)?.value
+          as DateTime?;
 
   ///Gets the notAfter date from the validity period of the certificate.
-  DateTime get notAfter {
-    var value = block1
-        .atIndex(X509BlockPosition.dateValidity)
+  DateTime? get notAfter {
+    var value = block1?.atIndex(X509BlockPosition.dateValidity)
         ?.subAtIndex(1)
-        ?.value as DateTime;
+        ?.value as DateTime?;
     return value;
   }
 
   ///Gets the signature value (the raw signature bits) from the certificate.
-  List<int> get signature => asn1[0].subAtIndex(2)?.value as List<int>;
+  List<int>? get signature =>  asn1?[0].subAtIndex(2)?.value as List<int>;
 
   ///Gets the signature algorithm name for the certificate signature algorithm.
-  String get sigAlgName => OID.fromValue(sigAlgOID ?? "")?.name();
+  String? get sigAlgName => OID.fromValue(sigAlgOID ?? '')?.name();
 
   ///Gets the signature algorithm OID string from the certificate.
-  String get sigAlgOID => block1.subAtIndex(2)?.subAtIndex(0)?.value as String;
+  String? get sigAlgOID => block1?.subAtIndex(2)?.subAtIndex(0)?.value as String?;
 
   ///Gets the DER-encoded signature algorithm parameters from this certificate's signature algorithm.
-  List<int> get sigAlgParams => null;
+  List<int>? get sigAlgParams => null;
 
   ///Gets a boolean array representing bits of the KeyUsage extension, (OID = 2.5.29.15).
   ///```
@@ -256,12 +256,12 @@ class X509Certificate {
   ///```
   List<bool> get keyUsage {
     var result = <bool>[];
-    var oidBlock = block1.findOid(oid: OID.keyUsage);
+    var oidBlock = block1?.findOid(oid: OID.keyUsage);
     if (oidBlock != null) {
       var sub = oidBlock.parent?.sub;
       if (sub != null && sub.length > 0) {
-        var data = sub.last.subAtIndex(0)?.value as List<int>;
-        int bits = (data != null && data.length > 0) ? data.first ?? 0 : 0;
+        var data = sub.last.subAtIndex(0)?.value as List<int>?;
+        int bits = (data != null && data.length > 0) ? data.first : 0;
         for (var index = 0; index < 8; index++) {
           var value = bits & (1 << index).toUnsigned(8) != 0;
           result.insert(0, value);
@@ -285,8 +285,8 @@ class X509Certificate {
       extensionObject(oid: OID.issuerAltName)?.valueAsStrings ?? <String>[];
 
   ///Gets the informations of the public key from this certificate.
-  X509PublicKey get publicKey {
-    var pkBlock = block1.atIndex(X509BlockPosition.publicKey);
+  X509PublicKey? get publicKey {
+    var pkBlock = block1?.atIndex(X509BlockPosition.publicKey);
     if (pkBlock != null) {
       return X509PublicKey(pkBlock: pkBlock);
     }
@@ -302,7 +302,7 @@ class X509Certificate {
     return extensionBlocks
         .map((block) => X509Extension(block: block))
         .where((extension) => extension.isCritical)
-        .map((extension) => extension.oid)
+        .map((extension) => extension.oid ?? '')
         .toList();
   }
 
@@ -315,7 +315,7 @@ class X509Certificate {
     return extensionBlocks
         .map((block) => X509Extension(block: block))
         .where((extension) => !extension.isCritical)
-        .map((extension) => extension.oid)
+        .map((extension) => extension.oid ?? '')
         .toList();
   }
 
@@ -362,7 +362,7 @@ class X509Certificate {
           ?.firstSub()
           ?.sub
           ?.map((e) => e.firstSub()?.value as String)
-          ?.toList() ??
+          .toList() ??
       <String>[];
 
   ///Gets the list of CRL distribution points from the CRLDistributionPoints extension, (OID = 2.5.29.31).
@@ -373,7 +373,7 @@ class X509Certificate {
           ?.firstSub()
           ?.sub
           ?.map((e) => e.firstSub()?.firstSub()?.firstSub()?.value as String)
-          ?.toList() ??
+          .toList() ??
       <String>[];
 
   ///Gets the map of the format (as a key) and location (as a value) of additional information
@@ -390,24 +390,23 @@ class X509Certificate {
       sub.forEach((element) {
         if (element.subCount() > 1) {
           result.putIfAbsent(
-              element.subAtIndex(0).value, () => element.subAtIndex(1).value);
+              element.subAtIndex(0)!.value, () => element.subAtIndex(1)!.value);
         }
       });
     }
     return result;
   }
 
-  List<ASN1Object> get extensionBlocks =>
-      block1.atIndex(X509BlockPosition.extensions)?.subAtIndex(0)?.sub;
+  List<ASN1Object>? get extensionBlocks =>
+      block1?.atIndex(X509BlockPosition.extensions)?.subAtIndex(0)?.sub;
 
   ///Gets the extension information of the given OID code or enum string value.
-  X509Extension extensionObject({String oidValue, OID oid}) {
+  X509Extension? extensionObject({String? oidValue, OID? oid}) {
     if (oidValue == null && oid != null) {
       oidValue = oid.toValue();
     }
     if (oidValue != null) {
-      var block = block1
-          .atIndex(X509BlockPosition.extensions)
+      var block = block1?.atIndex(X509BlockPosition.extensions)
           ?.findOid(oidValue: oidValue)
           ?.parent;
       if (block != null) {
@@ -418,7 +417,7 @@ class X509Certificate {
   }
 
   ///Format subject/issuer information in RFC1779
-  String blockDistinguishedName({@required ASN1Object block}) {
+  String blockDistinguishedName({required ASN1Object block}) {
     var result = "";
     for (var oidName in ASN1DistinguishedNames.values) {
       var oidBlock = block.findOid(oidValue: oidName.oid());
@@ -431,7 +430,7 @@ class X509Certificate {
 
         var sub = oidBlock.parent?.sub;
         if (sub != null && sub.length > 0) {
-          var value = sub.last.value as String;
+          var value = sub.last.value as String?;
           if (value != null) {
             var specialChar = ",+=\n<>#;\\";
             var quote = "";
@@ -490,10 +489,13 @@ class X509Certificate {
   }
 }
 
-dynamic firstLeafValue({@required ASN1Object block}) {
+dynamic firstLeafValue({required ASN1Object block}) {
   var sub = block.sub;
   if (sub != null && sub.length > 0) {
-    var subFirst = sub.first;
+    ASN1Object? subFirst;
+    try {
+      subFirst = sub.first;
+    } catch (e) {}
     if (subFirst != null) {
       return firstLeafValue(block: subFirst);
     }
diff --git a/lib/src/X509Certificate/x509_extension.dart b/lib/src/X509Certificate/x509_extension.dart
index afe17e31..3254561a 100644
--- a/lib/src/X509Certificate/x509_extension.dart
+++ b/lib/src/X509Certificate/x509_extension.dart
@@ -3,25 +3,28 @@ import 'asn1_object.dart';
 import 'oid.dart';
 
 class X509Extension {
-  ASN1Object block;
+  ASN1Object? block;
 
-  X509Extension({this.block});
+  X509Extension({required this.block});
 
-  String get oid => block.subAtIndex(0)?.value;
+  String? get oid => block?.subAtIndex(0)?.value;
 
-  String get name => OID.fromValue(oid ?? "")?.name();
+  String? get name => OID.fromValue(oid)?.name();
 
   bool get isCritical {
-    if ((block.sub?.length ?? 0) > 2) {
-      return block.subAtIndex(1)?.value ?? false;
+    if ((block?.sub?.length ?? 0) > 2) {
+      return block?.subAtIndex(1)?.value ?? false;
     }
     return false;
   }
 
   dynamic get value {
-    var sub = block.sub;
+    var sub = block?.sub;
     if (sub != null && sub.length > 0) {
-      var valueBlock = sub.last;
+      ASN1Object? valueBlock;
+      try {
+        valueBlock = sub.last;
+      } catch (e) {}
       if (valueBlock != null) {
         return firstLeafValue(block: valueBlock);
       }
@@ -29,19 +32,23 @@ class X509Extension {
     return null;
   }
 
-  ASN1Object get valueAsBlock {
-    var sub = block.sub;
+  ASN1Object? get valueAsBlock {
+    var sub = block?.sub;
     if (sub != null && sub.length > 0) {
-      return sub.last;
+      ASN1Object? valueBlock;
+      try {
+        valueBlock = sub.last;
+      } catch (e) {}
+      return valueBlock;
     }
     return null;
   }
 
   List<String> get valueAsStrings {
     var result = <String>[];
-    var sub;
+    var sub = <ASN1Object>[];
     try {
-      sub = block.sub?.last?.sub?.last?.sub ?? <ASN1Object>[];
+      sub = block?.sub?.last.sub?.last.sub ?? <ASN1Object>[];
     } catch (e) {}
 
     for (var item in sub) {
diff --git a/lib/src/X509Certificate/x509_public_key.dart b/lib/src/X509Certificate/x509_public_key.dart
index 6f31c712..ffd61698 100644
--- a/lib/src/X509Certificate/x509_public_key.dart
+++ b/lib/src/X509Certificate/x509_public_key.dart
@@ -5,17 +5,17 @@ import 'asn1_object.dart';
 import 'oid.dart';
 
 class X509PublicKey {
-  ASN1Object pkBlock;
+  ASN1Object? pkBlock;
 
   X509PublicKey({this.pkBlock});
 
-  String get algOid => pkBlock?.subAtIndex(0)?.subAtIndex(0)?.value;
+  String? get algOid => pkBlock?.subAtIndex(0)?.subAtIndex(0)?.value;
 
-  String get algName => OID.fromValue(algOid ?? "")?.name();
+  String? get algName => OID.fromValue(algOid)?.name();
 
-  String get algParams => pkBlock?.subAtIndex(0)?.subAtIndex(1)?.value;
+  String? get algParams => pkBlock?.subAtIndex(0)?.subAtIndex(1)?.value;
 
-  Uint8List get encoded {
+  Uint8List? get encoded {
     var oid = OID.fromValue(algOid);
     var keyData = pkBlock?.subAtIndex(1)?.value ?? null;
 
@@ -23,7 +23,7 @@ class X509PublicKey {
       if (oid == OID.ecPublicKey) {
         return Uint8List.fromList(keyData);
       } else if (oid == OID.rsaEncryption) {
-        List<ASN1Object> publicKeyAsn1Objects;
+        List<ASN1Object>? publicKeyAsn1Objects;
         try {
           publicKeyAsn1Objects =
               ASN1DERDecoder.decode(data: keyData.toList(growable: true));
@@ -31,7 +31,7 @@ class X509PublicKey {
 
         if (publicKeyAsn1Objects != null && publicKeyAsn1Objects.length > 0) {
           var publicKeyModulus =
-              publicKeyAsn1Objects.first?.subAtIndex(0)?.value;
+              publicKeyAsn1Objects.first.subAtIndex(0)?.value;
           if (publicKeyModulus != null) {
             return Uint8List.fromList(publicKeyModulus);
           }
diff --git a/lib/src/chrome_safari_browser.dart b/lib/src/chrome_safari_browser.dart
index f1aeb501..33756c8e 100755
--- a/lib/src/chrome_safari_browser.dart
+++ b/lib/src/chrome_safari_browser.dart
@@ -1,7 +1,6 @@
 import 'dart:async';
 import 'dart:collection';
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 import 'types.dart';
@@ -12,11 +11,11 @@ import 'in_app_browser.dart';
 ///
 ///[browserFallback] represents the [InAppBrowser] instance fallback in case `Chrome Custom Tabs`/`SFSafariViewController` is not available.
 class ChromeSafariBrowser {
-  String uuid;
-  InAppBrowser browserFallback;
+  late String uuid;
+  InAppBrowser? browserFallback;
   Map<int, ChromeSafariBrowserMenuItem> _menuItems = new HashMap();
   bool _isOpened = false;
-  MethodChannel _channel;
+  late MethodChannel _channel;
   static const MethodChannel _sharedChannel =
       const MethodChannel('com.pichillilorenzo/flutter_chromesafaribrowser');
 
@@ -46,7 +45,9 @@ class ChromeSafariBrowser {
         String url = call.arguments["url"];
         String title = call.arguments["title"];
         int id = call.arguments["id"].toInt();
-        this._menuItems[id].action(url, title);
+        if (this._menuItems[id] != null) {
+          this._menuItems[id]!.action(url, title);
+        }
         break;
       default:
         throw UnimplementedError("Unimplemented ${call.method} method");
@@ -65,14 +66,14 @@ class ChromeSafariBrowser {
   ///
   ///[contextMenuFallback]: Context Menu used by the [InAppBrowser] instance fallback.
   Future<void> open(
-      {@required String url,
-      ChromeSafariBrowserClassOptions options,
-      Map<String, String> headersFallback = const {},
-      InAppBrowserClassOptions optionsFallback}) async {
-    assert(url != null && url.isNotEmpty);
+      {required String url,
+      ChromeSafariBrowserClassOptions? options,
+      Map<String, String>? headersFallback = const {},
+      InAppBrowserClassOptions? optionsFallback}) async {
+    assert(url.isNotEmpty);
     this.throwIsAlreadyOpened(message: 'Cannot open $url!');
 
-    List<Map<String, dynamic>> menuItemList = new List();
+    List<Map<String, dynamic>> menuItemList = [];
     _menuItems.forEach((key, value) {
       menuItemList.add({"id": value.id, "label": value.label});
     });
@@ -160,7 +161,7 @@ class ChromeSafariBrowserMenuItem {
   final void Function(String url, String title) action;
 
   ChromeSafariBrowserMenuItem(
-      {@required this.id, @required this.label, @required this.action});
+      {required this.id, required this.label, required this.action});
 
   Map<String, dynamic> toMap() {
     return {"id": id, "label": label};
diff --git a/lib/src/content_blocker.dart b/lib/src/content_blocker.dart
index abf460ec..d4f99d15 100755
--- a/lib/src/content_blocker.dart
+++ b/lib/src/content_blocker.dart
@@ -15,7 +15,7 @@ class ContentBlocker {
   ///Action associated to the trigger. The action tells to the WebView what to do when the trigger is matched.
   ContentBlockerAction action;
 
-  ContentBlocker({@required this.trigger, @required this.action});
+  ContentBlocker({required this.trigger, required this.action});
 
   Map<String, Map<String, dynamic>> toMap() {
     return {"trigger": trigger.toMap(), "action": action.toMap()};
@@ -24,9 +24,9 @@ class ContentBlocker {
   static ContentBlocker fromMap(Map<dynamic, Map<dynamic, dynamic>> map) {
     return ContentBlocker(
         trigger: ContentBlockerTrigger.fromMap(
-            Map<String, dynamic>.from(map["trigger"])),
+            Map<String, dynamic>.from(map["trigger"]!)),
         action: ContentBlockerAction.fromMap(
-            Map<String, dynamic>.from(map["action"])));
+            Map<String, dynamic>.from(map["action"]!)));
   }
 }
 
@@ -36,36 +36,36 @@ class ContentBlocker {
 ///For example, you can limit the trigger to specific domains or have it not apply when a match is found on a specific domain.
 class ContentBlockerTrigger {
   ///A regular expression pattern to match the URL against.
-  String urlFilter;
+  late String urlFilter;
 
   ///Used only by iOS. A Boolean value. The default value is false.
-  bool urlFilterIsCaseSensitive;
+  late bool urlFilterIsCaseSensitive;
 
   ///A list of [ContentBlockerTriggerResourceType] representing the resource types (how the browser intends to use the resource) that the rule should match.
   ///If not specified, the rule matches all resource types.
-  List<ContentBlockerTriggerResourceType> resourceType;
+  late List<ContentBlockerTriggerResourceType> resourceType;
 
   ///A list of strings matched to a URL's domain; limits action to a list of specific domains.
   ///Values must be lowercase ASCII, or punycode for non-ASCII. Add * in front to match domain and subdomains. Can't be used with [ContentBlockerTrigger.unlessDomain].
-  List<String> ifDomain;
+  late List<String> ifDomain;
 
   ///A list of strings matched to a URL's domain; acts on any site except domains in a provided list.
   ///Values must be lowercase ASCII, or punycode for non-ASCII. Add * in front to match domain and subdomains. Can't be used with [ContentBlockerTrigger.ifDomain].
-  List<String> unlessDomain;
+  late List<String> unlessDomain;
 
   ///A list of [ContentBlockerTriggerLoadType] that can include one of two mutually exclusive values. If not specified, the rule matches all load types.
-  List<ContentBlockerTriggerLoadType> loadType;
+  late List<ContentBlockerTriggerLoadType> loadType;
 
   ///A list of strings matched to the entire main document URL; limits the action to a specific list of URL patterns.
   ///Values must be lowercase ASCII, or punycode for non-ASCII. Can't be used with [ContentBlockerTrigger.unlessTopUrl].
-  List<String> ifTopUrl;
+  late List<String> ifTopUrl;
 
   ///An array of strings matched to the entire main document URL; acts on any site except URL patterns in provided list.
   ///Values must be lowercase ASCII, or punycode for non-ASCII. Can't be used with [ContentBlockerTrigger.ifTopUrl].
-  List<String> unlessTopUrl;
+  late List<String> unlessTopUrl;
 
   ContentBlockerTrigger(
-      {@required String urlFilter,
+      {required String urlFilter,
       bool urlFilterIsCaseSensitive = false,
       List<ContentBlockerTriggerResourceType> resourceType = const [],
       List<String> ifDomain = const [],
@@ -74,7 +74,6 @@ class ContentBlockerTrigger {
       List<String> ifTopUrl = const [],
       List<String> unlessTopUrl = const []}) {
     this.urlFilter = urlFilter;
-    assert(this.urlFilter != null);
     this.resourceType = resourceType;
     this.urlFilterIsCaseSensitive = urlFilterIsCaseSensitive;
     this.ifDomain = ifDomain;
@@ -124,13 +123,19 @@ class ContentBlockerTrigger {
 
     List<String> resourceTypeStringList =
         List<String>.from(map["resource-type"] ?? []);
-    resourceTypeStringList.forEach((type) {
-      resourceType.add(ContentBlockerTriggerResourceType.fromValue(type));
+    resourceTypeStringList.forEach((typeValue) {
+      var type = ContentBlockerTriggerResourceType.fromValue(typeValue);
+      if (type != null) {
+        resourceType.add(type);
+      }
     });
 
     List<String> loadTypeStringList = List<String>.from(map["load-type"] ?? []);
-    loadTypeStringList.forEach((type) {
-      loadType.add(ContentBlockerTriggerLoadType.fromValue(type));
+    loadTypeStringList.forEach((typeValue) {
+      var type = ContentBlockerTriggerLoadType.fromValue(typeValue);
+      if (type != null) {
+        loadType.add(type);
+      }
     });
 
     return ContentBlockerTrigger(
@@ -152,16 +157,15 @@ class ContentBlockerTrigger {
 ///Group the rules with similar actions together to improve performance.
 class ContentBlockerAction {
   ///Type of the action.
-  ContentBlockerActionType type;
+  late ContentBlockerActionType type;
 
   ///If the action type is [ContentBlockerActionType.CSS_DISPLAY_NONE], then also the [selector] property is required, otherwise it is ignored.
   ///It specify a string that defines a selector list. Use CSS identifiers as the individual selector values, separated by commas.
-  String selector;
+  String? selector;
 
   ContentBlockerAction(
-      {@required ContentBlockerActionType type, String selector}) {
+      {required ContentBlockerActionType type, String? selector}) {
     this.type = type;
-    assert(this.type != null);
     if (this.type == ContentBlockerActionType.CSS_DISPLAY_NONE) {
       assert(selector != null);
     }
@@ -183,7 +187,7 @@ class ContentBlockerAction {
 
   static ContentBlockerAction fromMap(Map<String, dynamic> map) {
     return ContentBlockerAction(
-        type: ContentBlockerActionType.fromValue(map["type"]),
+        type: ContentBlockerActionType.fromValue(map["type"])!,
         selector: map["selector"]);
   }
 }
diff --git a/lib/src/context_menu.dart b/lib/src/context_menu.dart
index a42ba0e7..5f4ba03b 100644
--- a/lib/src/context_menu.dart
+++ b/lib/src/context_menu.dart
@@ -10,20 +10,20 @@ class ContextMenu {
   ///Event fired when the context menu for this WebView is being built.
   ///
   ///[hitTestResult] represents the hit result for hitting an HTML elements.
-  final void Function(InAppWebViewHitTestResult hitTestResult)
+  final void Function(InAppWebViewHitTestResult hitTestResult)?
       onCreateContextMenu;
 
   ///Event fired when the context menu for this WebView is being hidden.
-  final void Function() onHideContextMenu;
+  final void Function()? onHideContextMenu;
 
   ///Event fired when a context menu item has been clicked.
   ///
   ///[contextMenuItemClicked] represents the [ContextMenuItem] clicked.
-  final void Function(ContextMenuItem contextMenuItemClicked)
+  final void Function(ContextMenuItem contextMenuItemClicked)?
       onContextMenuActionItemClicked;
 
   ///Context menu options.
-  final ContextMenuOptions options;
+  final ContextMenuOptions? options;
 
   ///List of the custom [ContextMenuItem].
   final List<ContextMenuItem> menuItems;
@@ -33,12 +33,11 @@ class ContextMenu {
       this.onCreateContextMenu,
       this.onHideContextMenu,
       this.options,
-      this.onContextMenuActionItemClicked})
-      : assert(menuItems != null);
+      this.onContextMenuActionItemClicked});
 
   Map<String, dynamic> toMap() {
     return {
-      "menuItems": menuItems.map((menuItem) => menuItem?.toMap()).toList(),
+      "menuItems": menuItems.map((menuItem) => menuItem.toMap()).toList(),
       "options": options?.toMap()
     };
   }
@@ -56,21 +55,21 @@ class ContextMenu {
 ///Class that represent an item of the [ContextMenu].
 class ContextMenuItem {
   ///Android menu item ID.
-  int androidId;
+  int? androidId;
 
   ///iOS menu item ID.
-  String iosId;
+  String? iosId;
 
   ///Menu item title.
   String title;
 
   ///Menu item action that will be called when an user clicks on it.
-  Function() action;
+  Function()? action;
 
   ContextMenuItem(
-      {@required this.androidId,
-      @required this.iosId,
-      @required this.title,
+      {this.androidId,
+      this.iosId,
+      required this.title,
       this.action});
 
   Map<String, dynamic> toMap() {
diff --git a/lib/src/cookie_manager.dart b/lib/src/cookie_manager.dart
index 2c33d80a..dc738ac1 100755
--- a/lib/src/cookie_manager.dart
+++ b/lib/src/cookie_manager.dart
@@ -1,6 +1,5 @@
 import 'dart:async';
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 import 'types.dart';
@@ -11,19 +10,19 @@ import 'types.dart';
 ///
 ///**NOTE for iOS**: available from iOS 11.0+.
 class CookieManager {
-  static CookieManager _instance;
+  static CookieManager? _instance;
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_cookiemanager');
 
   ///Gets the cookie manager shared instance.
   static CookieManager instance() {
-    return (_instance != null) ? _instance : _init();
+    return (_instance != null) ? _instance! : _init();
   }
 
   static CookieManager _init() {
     _channel.setMethodCallHandler(_handleMethod);
     _instance = CookieManager();
-    return _instance;
+    return _instance!;
   }
 
   static Future<dynamic> _handleMethod(MethodCall call) async {}
@@ -33,23 +32,23 @@ class CookieManager {
   ///The default value of [path] is `"/"`.
   ///If [domain] is `null`, its default value will be the domain name of [url].
   Future<void> setCookie(
-      {@required String url,
-      @required String name,
-      @required String value,
-      String domain,
+      {required String url,
+      required String name,
+      required String value,
+      String? domain,
       String path = "/",
-      int expiresDate,
-      int maxAge,
-      bool isSecure,
-      bool isHttpOnly,
-      HTTPCookieSameSitePolicy sameSite}) async {
+      int? expiresDate,
+      int? maxAge,
+      bool? isSecure,
+      bool? isHttpOnly,
+      HTTPCookieSameSitePolicy? sameSite}) async {
     if (domain == null) domain = _getDomainName(url);
 
-    assert(url != null && url.isNotEmpty);
-    assert(name != null && name.isNotEmpty);
-    assert(value != null && value.isNotEmpty);
-    assert(domain != null && domain.isNotEmpty);
-    assert(path != null && path.isNotEmpty);
+    assert(url.isNotEmpty);
+    assert(name.isNotEmpty);
+    assert(value.isNotEmpty);
+    assert(domain.isNotEmpty);
+    assert(path.isNotEmpty);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
@@ -67,8 +66,8 @@ class CookieManager {
   }
 
   ///Gets all the cookies for the given [url].
-  Future<List<Cookie>> getCookies({@required String url}) async {
-    assert(url != null && url.isNotEmpty);
+  Future<List<Cookie>> getCookies({required String url}) async {
+    assert(url.isNotEmpty);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
@@ -94,10 +93,10 @@ class CookieManager {
   }
 
   ///Gets a cookie by its [name] for the given [url].
-  Future<Cookie> getCookie(
-      {@required String url, @required String name}) async {
-    assert(url != null && url.isNotEmpty);
-    assert(name != null && name.isNotEmpty);
+  Future<Cookie?> getCookie(
+      {required String url, required String name}) async {
+    assert(url.isNotEmpty);
+    assert(name.isNotEmpty);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
@@ -126,16 +125,16 @@ class CookieManager {
   ///The default value of [path] is `"/"`.
   ///If [domain] is `null` or empty, its default value will be the domain name of [url].
   Future<void> deleteCookie(
-      {@required String url,
-      @required String name,
+      {required String url,
+      required String name,
       String domain = "",
       String path = "/"}) async {
-    if (domain == null || domain.isEmpty) domain = _getDomainName(url);
+    if (domain.isEmpty) domain = _getDomainName(url);
 
-    assert(url != null && url.isNotEmpty);
-    assert(name != null && name.isNotEmpty);
-    assert(domain != null && url.isNotEmpty);
-    assert(path != null && url.isNotEmpty);
+    assert(url.isNotEmpty);
+    assert(name.isNotEmpty);
+    assert(url.isNotEmpty);
+    assert(url.isNotEmpty);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
@@ -150,12 +149,12 @@ class CookieManager {
   ///The default value of [path] is `"/"`.
   ///If [domain] is `null` or empty, its default value will be the domain name of [url].
   Future<void> deleteCookies(
-      {@required String url, String domain = "", String path = "/"}) async {
-    if (domain == null || domain.isEmpty) domain = _getDomainName(url);
+      {required String url, String domain = "", String path = "/"}) async {
+    if (domain.isEmpty) domain = _getDomainName(url);
 
-    assert(url != null && url.isNotEmpty);
-    assert(domain != null && url.isNotEmpty);
-    assert(path != null && url.isNotEmpty);
+    assert(url.isNotEmpty);
+    assert(url.isNotEmpty);
+    assert(url.isNotEmpty);
 
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
@@ -173,6 +172,7 @@ class CookieManager {
   String _getDomainName(String url) {
     Uri uri = Uri.parse(url);
     String domain = uri.host;
+    // ignore: unnecessary_null_comparison
     if (domain == null) return "";
     return domain.startsWith("www.") ? domain.substring(4) : domain;
   }
diff --git a/lib/src/headless_in_app_webview.dart b/lib/src/headless_in_app_webview.dart
index 5906a715..d6aed9b1 100644
--- a/lib/src/headless_in_app_webview.dart
+++ b/lib/src/headless_in_app_webview.dart
@@ -12,16 +12,16 @@ import 'in_app_webview_controller.dart';
 ///
 ///Remember to dispose it when you don't need it anymore.
 class HeadlessInAppWebView implements WebView {
-  String uuid;
+  late String uuid;
   bool _isDisposed = true;
   static const MethodChannel _sharedChannel =
       const MethodChannel('com.pichillilorenzo/flutter_headless_inappwebview');
 
   ///WebView Controller that can be used to access the [InAppWebViewController] API.
-  InAppWebViewController webViewController;
+  late InAppWebViewController webViewController;
 
   ///The window id of a [CreateWindowRequest.windowId].
-  final int windowId;
+  final int? windowId;
 
   HeadlessInAppWebView(
       {this.windowId,
@@ -89,7 +89,9 @@ class HeadlessInAppWebView implements WebView {
   Future<dynamic> handleMethod(MethodCall call) async {
     switch (call.method) {
       case "onHeadlessWebViewCreated":
-        onWebViewCreated(webViewController);
+        if (onWebViewCreated != null) {
+          onWebViewCreated!(webViewController);
+        }
         break;
       default:
         return webViewController.handleMethod(call);
@@ -107,12 +109,13 @@ class HeadlessInAppWebView implements WebView {
     args.putIfAbsent(
         'params',
         () => <String, dynamic>{
-              'initialUrl': '${Uri.parse(this.initialUrl)}',
+              'initialUrl': this.initialUrl != null ? '${Uri.parse(this.initialUrl!)}' : '',
               'initialFile': this.initialFile,
               'initialData': this.initialData?.toMap(),
               'initialHeaders': this.initialHeaders,
               'initialOptions': this.initialOptions?.toMap() ?? {},
-              'contextMenu': this.contextMenu?.toMap() ?? {}
+              'contextMenu': this.contextMenu?.toMap() ?? {},
+              'windowId': this.windowId
             });
     await _sharedChannel.invokeMethod('createHeadlessWebView', args);
   }
@@ -129,242 +132,242 @@ class HeadlessInAppWebView implements WebView {
   }
 
   @override
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       androidOnGeolocationPermissionsHidePrompt;
 
   @override
-  final Future<GeolocationPermissionShowPromptResponse> Function(
-          InAppWebViewController controller, String origin)
+  final Future<GeolocationPermissionShowPromptResponse?> Function(
+          InAppWebViewController controller, String origin)?
       androidOnGeolocationPermissionsShowPrompt;
 
   @override
-  final Future<PermissionRequestResponse> Function(
+  final Future<PermissionRequestResponse?> Function(
       InAppWebViewController controller,
       String origin,
-      List<String> resources) androidOnPermissionRequest;
+      List<String> resources)? androidOnPermissionRequest;
 
   @override
-  final Future<SafeBrowsingResponse> Function(InAppWebViewController controller,
-      String url, SafeBrowsingThreat threatType) androidOnSafeBrowsingHit;
+  final Future<SafeBrowsingResponse?> Function(InAppWebViewController controller,
+      String url, SafeBrowsingThreat? threatType)? androidOnSafeBrowsingHit;
 
   @override
-  final InAppWebViewInitialData initialData;
+  final InAppWebViewInitialData? initialData;
 
   @override
-  final String initialFile;
+  final String? initialFile;
 
   @override
-  final Map<String, String> initialHeaders;
+  final Map<String, String>? initialHeaders;
 
   @override
-  final InAppWebViewGroupOptions initialOptions;
+  final InAppWebViewGroupOptions? initialOptions;
 
   @override
-  final ContextMenu contextMenu;
+  final ContextMenu? contextMenu;
 
   @override
-  final String initialUrl;
+  final String? initialUrl;
 
   @override
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String? url)?
       onPageCommitVisible;
 
   @override
-  final void Function(InAppWebViewController controller, String title)
+  final void Function(InAppWebViewController controller, String? title)?
       onTitleChanged;
 
   @override
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       iosOnDidReceiveServerRedirectForProvisionalNavigation;
 
   @override
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       iosOnWebContentProcessDidTerminate;
 
   @override
   final Future<AjaxRequestAction> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       onAjaxProgress;
 
   @override
-  final Future<AjaxRequestAction> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequestAction?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       onAjaxReadyStateChange;
 
   @override
   final void Function(
-          InAppWebViewController controller, ConsoleMessage consoleMessage)
+          InAppWebViewController controller, ConsoleMessage consoleMessage)?
       onConsoleMessage;
 
   @override
-  final Future<bool> Function(InAppWebViewController controller,
-      CreateWindowRequest createWindowRequest) onCreateWindow;
+  final Future<bool?> Function(InAppWebViewController controller,
+      CreateWindowRequest createWindowRequest)? onCreateWindow;
 
   @override
-  final void Function(InAppWebViewController controller) onCloseWindow;
+  final void Function(InAppWebViewController controller)? onCloseWindow;
 
   @override
-  final void Function(InAppWebViewController controller) onWindowFocus;
+  final void Function(InAppWebViewController controller)? onWindowFocus;
 
   @override
-  final void Function(InAppWebViewController controller) onWindowBlur;
+  final void Function(InAppWebViewController controller)? onWindowBlur;
 
   @override
-  final void Function(InAppWebViewController controller) androidOnRequestFocus;
+  final void Function(InAppWebViewController controller)? androidOnRequestFocus;
 
   @override
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String url)?
       onDownloadStart;
 
   @override
   final void Function(InAppWebViewController controller, int activeMatchOrdinal,
-      int numberOfMatches, bool isDoneCounting) onFindResultReceived;
+      int numberOfMatches, bool isDoneCounting)? onFindResultReceived;
 
   @override
-  final Future<JsAlertResponse> Function(
-          InAppWebViewController controller, JsAlertRequest jsAlertRequest)
+  final Future<JsAlertResponse?> Function(
+          InAppWebViewController controller, JsAlertRequest jsAlertRequest)?
       onJsAlert;
 
   @override
-  final Future<JsConfirmResponse> Function(
-          InAppWebViewController controller, JsConfirmRequest jsConfirmRequest)
+  final Future<JsConfirmResponse?> Function(
+          InAppWebViewController controller, JsConfirmRequest jsConfirmRequest)?
       onJsConfirm;
 
   @override
-  final Future<JsPromptResponse> Function(
-          InAppWebViewController controller, JsPromptRequest jsPromptRequest)
+  final Future<JsPromptResponse?> Function(
+          InAppWebViewController controller, JsPromptRequest jsPromptRequest)?
       onJsPrompt;
 
   @override
-  final void Function(InAppWebViewController controller, String url, int code,
-      String message) onLoadError;
+  final void Function(InAppWebViewController controller, String? url, int code,
+      String message)? onLoadError;
 
   @override
-  final void Function(InAppWebViewController controller, String url,
-      int statusCode, String description) onLoadHttpError;
+  final void Function(InAppWebViewController controller, String? url,
+      int statusCode, String description)? onLoadHttpError;
 
   @override
   final void Function(
-          InAppWebViewController controller, LoadedResource resource)
+          InAppWebViewController controller, LoadedResource resource)?
       onLoadResource;
 
   @override
-  final Future<CustomSchemeResponse> Function(
-          InAppWebViewController controller, String scheme, String url)
+  final Future<CustomSchemeResponse?> Function(
+          InAppWebViewController controller, String scheme, String url)?
       onLoadResourceCustomScheme;
 
   @override
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String? url)?
       onLoadStart;
 
   @override
-  final void Function(InAppWebViewController controller, String url) onLoadStop;
+  final void Function(InAppWebViewController controller, String? url)? onLoadStop;
 
   @override
   final void Function(InAppWebViewController controller,
-      InAppWebViewHitTestResult hitTestResult) onLongPressHitTestResult;
+      InAppWebViewHitTestResult hitTestResult)? onLongPressHitTestResult;
 
   @override
-  final void Function(InAppWebViewController controller, String url) onPrint;
+  final void Function(InAppWebViewController controller, String? url)? onPrint;
 
   @override
-  final void Function(InAppWebViewController controller, int progress)
+  final void Function(InAppWebViewController controller, int progress)?
       onProgressChanged;
 
   @override
-  final Future<ClientCertResponse> Function(
-          InAppWebViewController controller, ClientCertChallenge challenge)
+  final Future<ClientCertResponse?> Function(
+          InAppWebViewController controller, ClientCertChallenge challenge)?
       onReceivedClientCertRequest;
 
   @override
-  final Future<HttpAuthResponse> Function(
-          InAppWebViewController controller, HttpAuthChallenge challenge)
+  final Future<HttpAuthResponse?> Function(
+          InAppWebViewController controller, HttpAuthChallenge challenge)?
       onReceivedHttpAuthRequest;
 
   @override
-  final Future<ServerTrustAuthResponse> Function(
-          InAppWebViewController controller, ServerTrustChallenge challenge)
+  final Future<ServerTrustAuthResponse?> Function(
+          InAppWebViewController controller, ServerTrustChallenge challenge)?
       onReceivedServerTrustAuthRequest;
 
   @override
-  final void Function(InAppWebViewController controller, int x, int y)
+  final void Function(InAppWebViewController controller, int x, int y)?
       onScrollChanged;
 
   @override
   final void Function(
-          InAppWebViewController controller, String url, bool androidIsReload)
+          InAppWebViewController controller, String? url, bool? androidIsReload)?
       onUpdateVisitedHistory;
 
   @override
-  final void Function(InAppWebViewController controller) onWebViewCreated;
+  final void Function(InAppWebViewController controller)? onWebViewCreated;
 
   @override
-  final Future<AjaxRequest> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequest?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       shouldInterceptAjaxRequest;
 
   @override
-  final Future<FetchRequest> Function(
-          InAppWebViewController controller, FetchRequest fetchRequest)
+  final Future<FetchRequest?> Function(
+          InAppWebViewController controller, FetchRequest fetchRequest)?
       shouldInterceptFetchRequest;
 
   @override
-  final Future<ShouldOverrideUrlLoadingAction> Function(
+  final Future<ShouldOverrideUrlLoadingAction?> Function(
           InAppWebViewController controller,
-          ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest)
+          ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest)?
       shouldOverrideUrlLoading;
 
   @override
-  final void Function(InAppWebViewController controller) onEnterFullscreen;
+  final void Function(InAppWebViewController controller)? onEnterFullscreen;
 
   @override
-  final void Function(InAppWebViewController controller) onExitFullscreen;
+  final void Function(InAppWebViewController controller)? onExitFullscreen;
 
   @override
-  final Future<WebResourceResponse> Function(
-          InAppWebViewController controller, WebResourceRequest request)
+  final Future<WebResourceResponse?> Function(
+          InAppWebViewController controller, WebResourceRequest request)?
       androidShouldInterceptRequest;
 
   @override
-  final Future<WebViewRenderProcessAction> Function(
-          InAppWebViewController controller, String url)
+  final Future<WebViewRenderProcessAction?> Function(
+          InAppWebViewController controller, String? url)?
       androidOnRenderProcessUnresponsive;
 
   @override
-  final Future<WebViewRenderProcessAction> Function(
-          InAppWebViewController controller, String url)
+  final Future<WebViewRenderProcessAction?> Function(
+          InAppWebViewController controller, String? url)?
       androidOnRenderProcessResponsive;
 
   @override
   final void Function(
-          InAppWebViewController controller, RenderProcessGoneDetail detail)
+          InAppWebViewController controller, RenderProcessGoneDetail detail)?
       androidOnRenderProcessGone;
 
   @override
-  final Future<FormResubmissionAction> Function(
-      InAppWebViewController controller, String url) androidOnFormResubmission;
+  final Future<FormResubmissionAction?> Function(
+      InAppWebViewController controller, String? url)? androidOnFormResubmission;
 
   @override
   final void Function(
-          InAppWebViewController controller, double oldScale, double newScale)
+          InAppWebViewController controller, double oldScale, double newScale)?
       androidOnScaleChanged;
 
   @override
-  final void Function(InAppWebViewController controller, Uint8List icon)
+  final void Function(InAppWebViewController controller, Uint8List icon)?
       androidOnReceivedIcon;
 
   @override
   final void Function(
-          InAppWebViewController controller, String url, bool precomposed)
+          InAppWebViewController controller, String url, bool precomposed)?
       androidOnReceivedTouchIconUrl;
 
   @override
-  final Future<JsBeforeUnloadResponse> Function(
+  final Future<JsBeforeUnloadResponse?> Function(
       InAppWebViewController controller,
-      JsBeforeUnloadRequest jsBeforeUnloadRequest) androidOnJsBeforeUnload;
+      JsBeforeUnloadRequest jsBeforeUnloadRequest)? androidOnJsBeforeUnload;
 
   @override
   final void Function(
-          InAppWebViewController controller, LoginRequest loginRequest)
+          InAppWebViewController controller, LoginRequest loginRequest)?
       androidOnReceivedLoginRequest;
 }
diff --git a/lib/src/http_auth_credentials_database.dart b/lib/src/http_auth_credentials_database.dart
index 66b5907c..b32e0a48 100755
--- a/lib/src/http_auth_credentials_database.dart
+++ b/lib/src/http_auth_credentials_database.dart
@@ -1,7 +1,5 @@
 import 'dart:async';
 
-import 'package:flutter/foundation.dart';
-
 import 'types.dart';
 import 'package:flutter/services.dart';
 
@@ -11,19 +9,19 @@ import 'package:flutter/services.dart';
 ///[WebViewDatabase](https://developer.android.com/reference/android/webkit/WebViewDatabase)
 ///doesn't offer the same functionalities as iOS `URLCredentialStorage`.
 class HttpAuthCredentialDatabase {
-  static HttpAuthCredentialDatabase _instance;
+  static HttpAuthCredentialDatabase? _instance;
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_credential_database');
 
   ///Gets the database shared instance.
   static HttpAuthCredentialDatabase instance() {
-    return (_instance != null) ? _instance : _init();
+    return (_instance != null) ? _instance! : _init();
   }
 
   static HttpAuthCredentialDatabase _init() {
     _channel.setMethodCallHandler(_handleMethod);
     _instance = HttpAuthCredentialDatabase();
-    return _instance;
+    return _instance!;
   }
 
   static Future<dynamic> _handleMethod(MethodCall call) async {}
@@ -59,7 +57,7 @@ class HttpAuthCredentialDatabase {
 
   ///Gets all the HTTP auth credentials saved for that [protectionSpace].
   Future<List<HttpAuthCredential>> getHttpAuthCredentials(
-      {@required ProtectionSpace protectionSpace}) async {
+      {required ProtectionSpace protectionSpace}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("host", () => protectionSpace.host);
     args.putIfAbsent("protocol", () => protectionSpace.protocol);
@@ -77,8 +75,8 @@ class HttpAuthCredentialDatabase {
 
   ///Saves an HTTP auth [credential] for that [protectionSpace].
   Future<void> setHttpAuthCredential(
-      {@required ProtectionSpace protectionSpace,
-      @required HttpAuthCredential credential}) async {
+      {required ProtectionSpace protectionSpace,
+      required HttpAuthCredential credential}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("host", () => protectionSpace.host);
     args.putIfAbsent("protocol", () => protectionSpace.protocol);
@@ -91,8 +89,8 @@ class HttpAuthCredentialDatabase {
 
   ///Removes an HTTP auth [credential] for that [protectionSpace].
   Future<void> removeHttpAuthCredential(
-      {@required ProtectionSpace protectionSpace,
-      @required HttpAuthCredential credential}) async {
+      {required ProtectionSpace protectionSpace,
+      required HttpAuthCredential credential}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("host", () => protectionSpace.host);
     args.putIfAbsent("protocol", () => protectionSpace.protocol);
@@ -105,7 +103,7 @@ class HttpAuthCredentialDatabase {
 
   ///Removes all the HTTP auth credentials saved for that [protectionSpace].
   Future<void> removeHttpAuthCredentials(
-      {@required ProtectionSpace protectionSpace}) async {
+      {required ProtectionSpace protectionSpace}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("host", () => protectionSpace.host);
     args.putIfAbsent("protocol", () => protectionSpace.protocol);
diff --git a/lib/src/in_app_browser.dart b/lib/src/in_app_browser.dart
index 4359705d..31951212 100755
--- a/lib/src/in_app_browser.dart
+++ b/lib/src/in_app_browser.dart
@@ -2,7 +2,6 @@ import 'dart:async';
 import 'dart:collection';
 import 'dart:typed_data';
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_inappwebview/flutter_inappwebview.dart';
 import 'context_menu.dart';
@@ -15,23 +14,23 @@ import 'types.dart';
 ///The [webViewController] field can be used to access the [InAppWebViewController] API.
 class InAppBrowser {
   ///Browser's UUID.
-  String uuid;
+  late String uuid;
 
   ///Context menu used by the browser. It should be set before opening the browser.
-  ContextMenu contextMenu;
+  ContextMenu? contextMenu;
 
   Map<String, JavaScriptHandlerCallback> javaScriptHandlersMap =
       HashMap<String, JavaScriptHandlerCallback>();
   bool _isOpened = false;
-  MethodChannel _channel;
+  late MethodChannel _channel;
   static const MethodChannel _sharedChannel =
       const MethodChannel('com.pichillilorenzo/flutter_inappbrowser');
 
   /// WebView Controller that can be used to access the [InAppWebViewController] API.
-  InAppWebViewController webViewController;
+  late InAppWebViewController webViewController;
 
   ///The window id of a [CreateWindowRequest.windowId].
-  final int windowId;
+  final int? windowId;
 
   ///
   InAppBrowser({this.windowId}) {
@@ -67,10 +66,10 @@ class InAppBrowser {
   ///
   ///[options]: Options for the [InAppBrowser].
   Future<void> openUrl(
-      {@required String url,
+      {required String url,
       Map<String, String> headers = const {},
-      InAppBrowserClassOptions options}) async {
-    assert(url != null && url.isNotEmpty);
+      InAppBrowserClassOptions? options}) async {
+    assert(url.isNotEmpty);
     this.throwIsAlreadyOpened(message: 'Cannot open $url!');
 
     Map<String, dynamic> args = <String, dynamic>{};
@@ -117,10 +116,10 @@ class InAppBrowser {
   ///
   ///[options]: Options for the [InAppBrowser].
   Future<void> openFile(
-      {@required String assetFilePath,
+      {required String assetFilePath,
       Map<String, String> headers = const {},
-      InAppBrowserClassOptions options}) async {
-    assert(assetFilePath != null && assetFilePath.isNotEmpty);
+      InAppBrowserClassOptions? options}) async {
+    assert(assetFilePath.isNotEmpty);
     this.throwIsAlreadyOpened(message: 'Cannot open $assetFilePath!');
 
     Map<String, dynamic> args = <String, dynamic>{};
@@ -143,14 +142,12 @@ class InAppBrowser {
   ///
   ///The [options] parameter specifies the options for the [InAppBrowser].
   Future<void> openData(
-      {@required String data,
+      {required String data,
       String mimeType = "text/html",
       String encoding = "utf8",
       String baseUrl = "about:blank",
       String androidHistoryUrl = "about:blank",
-      InAppBrowserClassOptions options}) async {
-    assert(data != null);
-
+      InAppBrowserClassOptions? options}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('uuid', () => uuid);
     args.putIfAbsent('options', () => options?.toMap() ?? {});
@@ -165,8 +162,8 @@ class InAppBrowser {
   }
 
   ///This is a static method that opens an [url] in the system browser. You wont be able to use the [InAppBrowser] methods here!
-  static Future<void> openWithSystemBrowser({@required String url}) async {
-    assert(url != null && url.isNotEmpty);
+  static Future<void> openWithSystemBrowser({required String url}) async {
+    assert(url.isNotEmpty);
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
     return await _sharedChannel.invokeMethod('openWithSystemBrowser', args);
@@ -202,24 +199,24 @@ class InAppBrowser {
   }
 
   ///Sets the [InAppBrowser] options with the new [options] and evaluates them.
-  Future<void> setOptions({@required InAppBrowserClassOptions options}) async {
+  Future<void> setOptions({required InAppBrowserClassOptions options}) async {
     this.throwIsNotOpened();
 
     Map<String, dynamic> args = <String, dynamic>{};
-    args.putIfAbsent('options', () => options?.toMap() ?? {});
+    args.putIfAbsent('options', () => options.toMap());
     await _channel.invokeMethod('setOptions', args);
   }
 
   ///Gets the current [InAppBrowser] options. Returns `null` if it wasn't able to get them.
-  Future<InAppBrowserClassOptions> getOptions() async {
+  Future<InAppBrowserClassOptions?> getOptions() async {
     this.throwIsNotOpened();
     Map<String, dynamic> args = <String, dynamic>{};
 
-    Map<dynamic, dynamic> options =
+    Map<dynamic, dynamic>? options =
         await _channel.invokeMethod('getOptions', args);
     if (options != null) {
       options = options.cast<String, dynamic>();
-      return InAppBrowserClassOptions.fromMap(options);
+      return InAppBrowserClassOptions.fromMap(options as Map<String, dynamic>);
     }
 
     return null;
@@ -241,21 +238,21 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onPageStarted(android.webkit.WebView,%20java.lang.String,%20android.graphics.Bitmap)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455621-webview
-  void onLoadStart(String url) {}
+  void onLoadStart(String? url) {}
 
   ///Event fired when the [InAppBrowser] finishes loading an [url].
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onPageFinished(android.webkit.WebView,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455629-webview
-  void onLoadStop(String url) {}
+  void onLoadStop(String? url) {}
 
   ///Event fired when the [InAppBrowser] encounters an error loading an [url].
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedError(android.webkit.WebView,%20int,%20java.lang.String,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455623-webview
-  void onLoadError(String url, int code, String message) {}
+  void onLoadError(String? url, int code, String message) {}
 
   ///Event fired when the [InAppBrowser] main page receives an HTTP error.
   ///
@@ -270,7 +267,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedHttpError(android.webkit.WebView,%20android.webkit.WebResourceRequest,%20android.webkit.WebResourceResponse)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455643-webview
-  void onLoadHttpError(String url, int statusCode, String description) {}
+  void onLoadHttpError(String? url, int statusCode, String description) {}
 
   ///Event fired when the current [progress] (range 0-100) of loading a page is changed.
   ///
@@ -297,8 +294,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#shouldOverrideUrlLoading(android.webkit.WebView,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455641-webview
-  // ignore: missing_return
-  Future<ShouldOverrideUrlLoadingAction> shouldOverrideUrlLoading(
+  Future<ShouldOverrideUrlLoadingAction?>? shouldOverrideUrlLoading(
       ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest) {}
 
   ///Event fired when the [InAppBrowser] webview loads a resource.
@@ -335,8 +331,7 @@ class InAppBrowser {
   ///[url] represents the url of the request.
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkurlschemehandler
-  // ignore: missing_return
-  Future<CustomSchemeResponse> onLoadResourceCustomScheme(
+  Future<CustomSchemeResponse?>? onLoadResourceCustomScheme(
       String scheme, String url) {}
 
   ///Event fired when the [InAppBrowser] webview requests the host application to create a new window,
@@ -369,8 +364,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onCreateWindow(android.webkit.WebView,%20boolean,%20boolean,%20android.os.Message)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1536907-webview
-  // ignore: missing_return
-  Future<bool> onCreateWindow(CreateWindowRequest createWindowRequest) {}
+  Future<bool?>? onCreateWindow(CreateWindowRequest createWindowRequest) {}
 
   ///Event fired when the host application should close the given WebView and remove it from the view system if necessary.
   ///At this point, WebCore has stopped any loading in this window and has removed any cross-scripting ability in javascript.
@@ -396,8 +390,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsAlert(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20android.webkit.JsResult)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1537406-webview
-  // ignore: missing_return
-  Future<JsAlertResponse> onJsAlert(JsAlertRequest jsAlertRequest) {}
+  Future<JsAlertResponse?>? onJsAlert(JsAlertRequest jsAlertRequest) {}
 
   ///Event fired when javascript calls the `confirm()` method to display a confirm dialog.
   ///If [JsConfirmResponse.handledByClient] is `true`, the webview will assume that the client will handle the dialog.
@@ -407,8 +400,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsConfirm(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20android.webkit.JsResult)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1536489-webview
-  // ignore: missing_return
-  Future<JsConfirmResponse> onJsConfirm(JsConfirmRequest jsConfirmRequest) {}
+  Future<JsConfirmResponse?>? onJsConfirm(JsConfirmRequest jsConfirmRequest) {}
 
   ///Event fired when javascript calls the `prompt()` method to display a prompt dialog.
   ///If [JsPromptResponse.handledByClient] is `true`, the webview will assume that the client will handle the dialog.
@@ -418,8 +410,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsPrompt(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20android.webkit.JsPromptResult)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1538086-webview
-  // ignore: missing_return
-  Future<JsPromptResponse> onJsPrompt(JsPromptRequest jsPromptRequest) {}
+  Future<JsPromptResponse?>? onJsPrompt(JsPromptRequest jsPromptRequest) {}
 
   ///Event fired when the WebView received an HTTP authentication request. The default behavior is to cancel the request.
   ///
@@ -428,8 +419,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedHttpAuthRequest(android.webkit.WebView,%20android.webkit.HttpAuthHandler,%20java.lang.String,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455638-webview
-  // ignore: missing_return
-  Future<HttpAuthResponse> onReceivedHttpAuthRequest(
+  Future<HttpAuthResponse?>? onReceivedHttpAuthRequest(
       HttpAuthChallenge challenge) {}
 
   ///Event fired when the WebView need to perform server trust authentication (certificate validation).
@@ -440,8 +430,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedSslError(android.webkit.WebView,%20android.webkit.SslErrorHandler,%20android.net.http.SslError)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455638-webview
-  // ignore: missing_return
-  Future<ServerTrustAuthResponse> onReceivedServerTrustAuthRequest(
+  Future<ServerTrustAuthResponse?>? onReceivedServerTrustAuthRequest(
       ServerTrustChallenge challenge) {}
 
   ///Notify the host application to handle an SSL client certificate request.
@@ -454,8 +443,7 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedClientCertRequest(android.webkit.WebView,%20android.webkit.ClientCertRequest)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455638-webview
-  // ignore: missing_return
-  Future<ClientCertResponse> onReceivedClientCertRequest(
+  Future<ClientCertResponse?>? onReceivedClientCertRequest(
       ClientCertChallenge challenge) {}
 
   ///Event fired as find-on-page operations progress.
@@ -477,8 +465,7 @@ class InAppBrowser {
   ///[ajaxRequest] represents the `XMLHttpRequest`.
   ///
   ///**NOTE**: In order to be able to listen this event, you need to set [InAppWebViewOptions.useShouldInterceptAjaxRequest] option to `true`.
-  // ignore: missing_return
-  Future<AjaxRequest> shouldInterceptAjaxRequest(AjaxRequest ajaxRequest) {}
+  Future<AjaxRequest?>? shouldInterceptAjaxRequest(AjaxRequest ajaxRequest) {}
 
   ///Event fired whenever the `readyState` attribute of an `XMLHttpRequest` changes.
   ///It gives the host application a chance to abort the request.
@@ -486,8 +473,7 @@ class InAppBrowser {
   ///[ajaxRequest] represents the [XMLHttpRequest].
   ///
   ///**NOTE**: In order to be able to listen this event, you need to set [InAppWebViewOptions.useShouldInterceptAjaxRequest] option to `true`.
-  // ignore: missing_return
-  Future<AjaxRequestAction> onAjaxReadyStateChange(AjaxRequest ajaxRequest) {}
+  Future<AjaxRequestAction?>? onAjaxReadyStateChange(AjaxRequest ajaxRequest) {}
 
   ///Event fired as an `XMLHttpRequest` progress.
   ///It gives the host application a chance to abort the request.
@@ -495,8 +481,7 @@ class InAppBrowser {
   ///[ajaxRequest] represents the [XMLHttpRequest].
   ///
   ///**NOTE**: In order to be able to listen this event, you need to set [InAppWebViewOptions.useShouldInterceptAjaxRequest] option to `true`.
-  // ignore: missing_return
-  Future<AjaxRequestAction> onAjaxProgress(AjaxRequest ajaxRequest) {}
+  Future<AjaxRequestAction?>? onAjaxProgress(AjaxRequest ajaxRequest) {}
 
   ///Event fired when a request is sent to a server through [Fetch API](https://developer.mozilla.org/it/docs/Web/API/Fetch_API).
   ///It gives the host application a chance to take control over the request before sending it.
@@ -504,8 +489,7 @@ class InAppBrowser {
   ///[fetchRequest] represents a resource request.
   ///
   ///**NOTE**: In order to be able to listen this event, you need to set [InAppWebViewOptions.useShouldInterceptFetchRequest] option to `true`.
-  // ignore: missing_return
-  Future<FetchRequest> shouldInterceptFetchRequest(FetchRequest fetchRequest) {}
+  Future<FetchRequest?>? shouldInterceptFetchRequest(FetchRequest fetchRequest) {}
 
   ///Event fired when the host application updates its visited links database.
   ///This event is also fired when the navigation state of the [InAppWebView] changes through the usage of
@@ -517,14 +501,14 @@ class InAppBrowser {
   ///[androidIsReload] indicates if this url is being reloaded. Available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#doUpdateVisitedHistory(android.webkit.WebView,%20java.lang.String,%20boolean)
-  void onUpdateVisitedHistory(String url, bool androidIsReload) {}
+  void onUpdateVisitedHistory(String? url, bool? androidIsReload) {}
 
   ///Event fired when `window.print()` is called from JavaScript side.
   ///
   ///[url] represents the url on which is called.
   ///
   ///**NOTE**: available on Android 21+.
-  void onPrint(String url) {}
+  void onPrint(String? url) {}
 
   ///Event fired when an HTML element of the webview has been clicked and held.
   ///
@@ -559,14 +543,14 @@ class InAppBrowser {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onPageCommitVisible(android.webkit.WebView,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455635-webview
-  void onPageCommitVisible(String url) {}
+  void onPageCommitVisible(String? url) {}
 
   ///Event fired when a change in the document title occurred.
   ///
   ///[title] represents the string containing the new title of the document.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onReceivedTitle(android.webkit.WebView,%20java.lang.String)
-  void onTitleChanged(String title) {}
+  void onTitleChanged(String? title) {}
 
   ///Event fired when the WebView notifies that a loading URL has been flagged by Safe Browsing.
   ///The default behavior is to show an interstitial to the user, with the reporting checkbox visible.
@@ -578,9 +562,8 @@ class InAppBrowser {
   ///**NOTE**: available only on Android 27+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onSafeBrowsingHit(android.webkit.WebView,%20android.webkit.WebResourceRequest,%20int,%20android.webkit.SafeBrowsingResponse)
-  // ignore: missing_return
-  Future<SafeBrowsingResponse> androidOnSafeBrowsingHit(
-      String url, SafeBrowsingThreat threatType) {}
+  Future<SafeBrowsingResponse?>? androidOnSafeBrowsingHit(
+      String url, SafeBrowsingThreat? threatType) {}
 
   ///Event fired when the WebView is requesting permission to access the specified resources and the permission currently isn't granted or denied.
   ///
@@ -591,8 +574,7 @@ class InAppBrowser {
   ///**NOTE**: available only on Android 23+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onPermissionRequest(android.webkit.PermissionRequest)
-  // ignore: missing_return
-  Future<PermissionRequestResponse> androidOnPermissionRequest(
+  Future<PermissionRequestResponse?>? androidOnPermissionRequest(
       String origin, List<String> resources) {}
 
   ///Event that notifies the host application that web content from the specified origin is attempting to use the Geolocation API, but no permission state is currently set for that origin.
@@ -604,8 +586,7 @@ class InAppBrowser {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onGeolocationPermissionsShowPrompt(java.lang.String,%20android.webkit.GeolocationPermissions.Callback)
-  Future<GeolocationPermissionShowPromptResponse>
-      // ignore: missing_return
+  Future<GeolocationPermissionShowPromptResponse?>?
       androidOnGeolocationPermissionsShowPrompt(String origin) {}
 
   ///Notify the host application that a request for Geolocation permissions, made with a previous call to [androidOnGeolocationPermissionsShowPrompt] has been canceled.
@@ -633,8 +614,7 @@ class InAppBrowser {
   ///**Official Android API**:
   ///- https://developer.android.com/reference/android/webkit/WebViewClient#shouldInterceptRequest(android.webkit.WebView,%20android.webkit.WebResourceRequest)
   ///- https://developer.android.com/reference/android/webkit/WebViewClient#shouldInterceptRequest(android.webkit.WebView,%20java.lang.String)
-  Future<WebResourceResponse>
-      // ignore: missing_return
+  Future<WebResourceResponse?>?
       androidShouldInterceptRequest(WebResourceRequest request) {}
 
   ///Event called when the renderer currently associated with the WebView becomes unresponsive as a result of a long running blocking task such as the execution of JavaScript.
@@ -655,9 +635,8 @@ class InAppBrowser {
   ///**NOTE**: available only on Android 29+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewRenderProcessClient#onRenderProcessUnresponsive(android.webkit.WebView,%20android.webkit.WebViewRenderProcess)
-  Future<WebViewRenderProcessAction>
-      // ignore: missing_return
-      androidOnRenderProcessUnresponsive(String url) {}
+  Future<WebViewRenderProcessAction?>?
+      androidOnRenderProcessUnresponsive(String? url) {}
 
   ///Event called once when an unresponsive renderer currently associated with the WebView becomes responsive.
   ///
@@ -670,9 +649,8 @@ class InAppBrowser {
   ///**NOTE**: available only on Android 29+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewRenderProcessClient#onRenderProcessResponsive(android.webkit.WebView,%20android.webkit.WebViewRenderProcess)
-  Future<WebViewRenderProcessAction>
-      // ignore: missing_return
-      androidOnRenderProcessResponsive(String url) {}
+  Future<WebViewRenderProcessAction?>?
+      androidOnRenderProcessResponsive(String? url) {}
 
   ///Event fired when the given WebView's render process has exited.
   ///The application's implementation of this callback should only attempt to clean up the WebView.
@@ -690,9 +668,8 @@ class InAppBrowser {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onFormResubmission(android.webkit.WebView,%20android.os.Message,%20android.os.Message)
-  Future<FormResubmissionAction>
-      // ignore: missing_return
-      androidOnFormResubmission(String url) {}
+  Future<FormResubmissionAction?>?
+      androidOnFormResubmission(String? url) {}
 
   ///Event fired when the scale applied to the WebView has changed.
   ///
@@ -746,8 +723,7 @@ class InAppBrowser {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsBeforeUnload(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20android.webkit.JsResult)
-  // ignore: missing_return
-  Future<JsBeforeUnloadResponse> androidOnJsBeforeUnload(
+  Future<JsBeforeUnloadResponse?>? androidOnJsBeforeUnload(
       JsBeforeUnloadRequest jsBeforeUnloadRequest) {}
 
   ///Event fired when a request to automatically log in the user has been processed.
diff --git a/lib/src/in_app_localhost_server.dart b/lib/src/in_app_localhost_server.dart
index 70634eeb..cd358159 100755
--- a/lib/src/in_app_localhost_server.dart
+++ b/lib/src/in_app_localhost_server.dart
@@ -6,7 +6,7 @@ import 'package:mime/mime.dart';
 
 ///This class allows you to create a simple server on `http://localhost:[port]/` in order to be able to load your assets file on a server. The default [port] value is `8080`.
 class InAppLocalhostServer {
-  HttpServer _server;
+  HttpServer? _server;
   int _port = 8080;
 
   InAppLocalhostServer({int port = 8080}) {
@@ -38,7 +38,7 @@ class InAppLocalhostServer {
         this._server = server;
 
         server.listen((HttpRequest request) async {
-          var body = List<int>();
+          var body = [] as List<int>;
           var path = request.requestedUri.path;
           path = (path.startsWith('/')) ? path.substring(1) : path;
           path += (path.endsWith('/')) ? 'index.html' : '';
@@ -77,7 +77,7 @@ class InAppLocalhostServer {
   ///Closes the server.
   Future<void> close() async {
     if (this._server != null) {
-      await this._server.close(force: true);
+      await this._server!.close(force: true);
       print('Server running on http://localhost:$_port closed');
       this._server = null;
     }
diff --git a/lib/src/in_app_webview.dart b/lib/src/in_app_webview.dart
index d9fbbebf..5013d405 100755
--- a/lib/src/in_app_webview.dart
+++ b/lib/src/in_app_webview.dart
@@ -22,13 +22,13 @@ class InAppWebView extends StatefulWidget implements WebView {
   /// recognizers on this list.
   /// When `gestureRecognizers` is empty or null, the web view will only handle pointer events for gestures that
   /// were not claimed by any other gesture recognizer.
-  final Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers;
+  final Set<Factory<OneSequenceGestureRecognizer>>? gestureRecognizers;
 
   ///The window id of a [CreateWindowRequest.windowId].
-  final int windowId;
+  final int? windowId;
 
   const InAppWebView({
-    Key key,
+    Key? key,
     this.windowId,
     this.initialUrl = "about:blank",
     this.initialFile,
@@ -94,248 +94,248 @@ class InAppWebView extends StatefulWidget implements WebView {
   _InAppWebViewState createState() => _InAppWebViewState();
 
   @override
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       androidOnGeolocationPermissionsHidePrompt;
 
   @override
-  final Future<GeolocationPermissionShowPromptResponse> Function(
-          InAppWebViewController controller, String origin)
+  final Future<GeolocationPermissionShowPromptResponse?> Function(
+          InAppWebViewController controller, String origin)?
       androidOnGeolocationPermissionsShowPrompt;
 
   @override
-  final Future<PermissionRequestResponse> Function(
+  final Future<PermissionRequestResponse?> Function(
       InAppWebViewController controller,
       String origin,
-      List<String> resources) androidOnPermissionRequest;
+      List<String> resources)? androidOnPermissionRequest;
 
   @override
-  final Future<SafeBrowsingResponse> Function(InAppWebViewController controller,
-      String url, SafeBrowsingThreat threatType) androidOnSafeBrowsingHit;
+  final Future<SafeBrowsingResponse?> Function(InAppWebViewController controller,
+      String url, SafeBrowsingThreat? threatType)? androidOnSafeBrowsingHit;
 
   @override
-  final InAppWebViewInitialData initialData;
+  final InAppWebViewInitialData? initialData;
 
   @override
-  final String initialFile;
+  final String? initialFile;
 
   @override
-  final Map<String, String> initialHeaders;
+  final Map<String, String>? initialHeaders;
 
   @override
-  final InAppWebViewGroupOptions initialOptions;
+  final InAppWebViewGroupOptions? initialOptions;
 
   @override
-  final String initialUrl;
+  final String? initialUrl;
 
   @override
-  final ContextMenu contextMenu;
+  final ContextMenu? contextMenu;
 
   @override
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String? url)?
       onPageCommitVisible;
 
   @override
-  final void Function(InAppWebViewController controller, String title)
+  final void Function(InAppWebViewController controller, String? title)?
       onTitleChanged;
 
   @override
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       iosOnDidReceiveServerRedirectForProvisionalNavigation;
 
   @override
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       iosOnWebContentProcessDidTerminate;
 
   @override
   final Future<AjaxRequestAction> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       onAjaxProgress;
 
   @override
-  final Future<AjaxRequestAction> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequestAction?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       onAjaxReadyStateChange;
 
   @override
   final void Function(
-          InAppWebViewController controller, ConsoleMessage consoleMessage)
+          InAppWebViewController controller, ConsoleMessage consoleMessage)?
       onConsoleMessage;
 
   @override
-  final Future<bool> Function(InAppWebViewController controller,
-      CreateWindowRequest createWindowRequest) onCreateWindow;
+  final Future<bool?> Function(InAppWebViewController controller,
+      CreateWindowRequest createWindowRequest)? onCreateWindow;
 
   @override
-  final void Function(InAppWebViewController controller) onCloseWindow;
+  final void Function(InAppWebViewController controller)? onCloseWindow;
 
   @override
-  final void Function(InAppWebViewController controller) onWindowFocus;
+  final void Function(InAppWebViewController controller)? onWindowFocus;
 
   @override
-  final void Function(InAppWebViewController controller) onWindowBlur;
+  final void Function(InAppWebViewController controller)? onWindowBlur;
 
   @override
-  final void Function(InAppWebViewController controller) androidOnRequestFocus;
+  final void Function(InAppWebViewController controller)? androidOnRequestFocus;
 
   @override
-  final void Function(InAppWebViewController controller, Uint8List icon)
+  final void Function(InAppWebViewController controller, Uint8List icon)?
       androidOnReceivedIcon;
 
   @override
   final void Function(
-          InAppWebViewController controller, String url, bool precomposed)
+          InAppWebViewController controller, String url, bool precomposed)?
       androidOnReceivedTouchIconUrl;
 
   @override
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String url)?
       onDownloadStart;
 
   @override
   final void Function(InAppWebViewController controller, int activeMatchOrdinal,
-      int numberOfMatches, bool isDoneCounting) onFindResultReceived;
+      int numberOfMatches, bool isDoneCounting)? onFindResultReceived;
 
   @override
-  final Future<JsAlertResponse> Function(
-          InAppWebViewController controller, JsAlertRequest jsAlertRequest)
+  final Future<JsAlertResponse?> Function(
+          InAppWebViewController controller, JsAlertRequest jsAlertRequest)?
       onJsAlert;
 
   @override
-  final Future<JsConfirmResponse> Function(
-          InAppWebViewController controller, JsConfirmRequest jsConfirmRequest)
+  final Future<JsConfirmResponse?> Function(
+          InAppWebViewController controller, JsConfirmRequest jsConfirmRequest)?
       onJsConfirm;
 
   @override
-  final Future<JsPromptResponse> Function(
-          InAppWebViewController controller, JsPromptRequest jsPromptRequest)
+  final Future<JsPromptResponse?> Function(
+          InAppWebViewController controller, JsPromptRequest jsPromptRequest)?
       onJsPrompt;
 
   @override
-  final void Function(InAppWebViewController controller, String url, int code,
-      String message) onLoadError;
+  final void Function(InAppWebViewController controller, String? url, int code,
+      String message)? onLoadError;
 
   @override
-  final void Function(InAppWebViewController controller, String url,
-      int statusCode, String description) onLoadHttpError;
+  final void Function(InAppWebViewController controller, String? url,
+      int statusCode, String description)? onLoadHttpError;
 
   @override
   final void Function(
-          InAppWebViewController controller, LoadedResource resource)
+          InAppWebViewController controller, LoadedResource resource)?
       onLoadResource;
 
   @override
-  final Future<CustomSchemeResponse> Function(
-          InAppWebViewController controller, String scheme, String url)
+  final Future<CustomSchemeResponse?> Function(
+          InAppWebViewController controller, String scheme, String url)?
       onLoadResourceCustomScheme;
 
   @override
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String? url)?
       onLoadStart;
 
   @override
-  final void Function(InAppWebViewController controller, String url) onLoadStop;
+  final void Function(InAppWebViewController controller, String? url)? onLoadStop;
 
   @override
   final void Function(InAppWebViewController controller,
-      InAppWebViewHitTestResult hitTestResult) onLongPressHitTestResult;
+      InAppWebViewHitTestResult hitTestResult)? onLongPressHitTestResult;
 
   @override
-  final void Function(InAppWebViewController controller, String url) onPrint;
+  final void Function(InAppWebViewController controller, String? url)? onPrint;
 
   @override
-  final void Function(InAppWebViewController controller, int progress)
+  final void Function(InAppWebViewController controller, int progress)?
       onProgressChanged;
 
   @override
-  final Future<ClientCertResponse> Function(
-          InAppWebViewController controller, ClientCertChallenge challenge)
+  final Future<ClientCertResponse?> Function(
+          InAppWebViewController controller, ClientCertChallenge challenge)?
       onReceivedClientCertRequest;
 
   @override
-  final Future<HttpAuthResponse> Function(
-          InAppWebViewController controller, HttpAuthChallenge challenge)
+  final Future<HttpAuthResponse?> Function(
+          InAppWebViewController controller, HttpAuthChallenge challenge)?
       onReceivedHttpAuthRequest;
 
   @override
-  final Future<ServerTrustAuthResponse> Function(
-          InAppWebViewController controller, ServerTrustChallenge challenge)
+  final Future<ServerTrustAuthResponse?> Function(
+          InAppWebViewController controller, ServerTrustChallenge challenge)?
       onReceivedServerTrustAuthRequest;
 
   @override
-  final void Function(InAppWebViewController controller, int x, int y)
+  final void Function(InAppWebViewController controller, int x, int y)?
       onScrollChanged;
 
   @override
   final void Function(
-          InAppWebViewController controller, String url, bool androidIsReload)
+          InAppWebViewController controller, String? url, bool? androidIsReload)?
       onUpdateVisitedHistory;
 
   @override
-  final void Function(InAppWebViewController controller) onWebViewCreated;
+  final void Function(InAppWebViewController controller)? onWebViewCreated;
 
   @override
-  final Future<AjaxRequest> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequest?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       shouldInterceptAjaxRequest;
 
   @override
-  final Future<FetchRequest> Function(
-          InAppWebViewController controller, FetchRequest fetchRequest)
+  final Future<FetchRequest?> Function(
+          InAppWebViewController controller, FetchRequest fetchRequest)?
       shouldInterceptFetchRequest;
 
   @override
-  final Future<ShouldOverrideUrlLoadingAction> Function(
+  final Future<ShouldOverrideUrlLoadingAction?> Function(
           InAppWebViewController controller,
-          ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest)
+          ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest)?
       shouldOverrideUrlLoading;
 
   @override
-  final void Function(InAppWebViewController controller) onEnterFullscreen;
+  final void Function(InAppWebViewController controller)? onEnterFullscreen;
 
   @override
-  final void Function(InAppWebViewController controller) onExitFullscreen;
+  final void Function(InAppWebViewController controller)? onExitFullscreen;
 
   @override
-  final Future<WebResourceResponse> Function(
-          InAppWebViewController controller, WebResourceRequest request)
+  final Future<WebResourceResponse?> Function(
+          InAppWebViewController controller, WebResourceRequest request)?
       androidShouldInterceptRequest;
 
   @override
-  final Future<WebViewRenderProcessAction> Function(
-          InAppWebViewController controller, String url)
+  final Future<WebViewRenderProcessAction?> Function(
+          InAppWebViewController controller, String? url)?
       androidOnRenderProcessUnresponsive;
 
   @override
-  final Future<WebViewRenderProcessAction> Function(
-          InAppWebViewController controller, String url)
+  final Future<WebViewRenderProcessAction?> Function(
+          InAppWebViewController controller, String? url)?
       androidOnRenderProcessResponsive;
 
   @override
   final void Function(
-          InAppWebViewController controller, RenderProcessGoneDetail detail)
+          InAppWebViewController controller, RenderProcessGoneDetail detail)?
       androidOnRenderProcessGone;
 
   @override
-  final Future<FormResubmissionAction> Function(
-      InAppWebViewController controller, String url) androidOnFormResubmission;
+  final Future<FormResubmissionAction?> Function(
+      InAppWebViewController controller, String? url)? androidOnFormResubmission;
 
   @override
   final void Function(
-          InAppWebViewController controller, double oldScale, double newScale)
+          InAppWebViewController controller, double oldScale, double newScale)?
       androidOnScaleChanged;
 
   @override
-  final Future<JsBeforeUnloadResponse> Function(
+  final Future<JsBeforeUnloadResponse?> Function(
       InAppWebViewController controller,
-      JsBeforeUnloadRequest jsBeforeUnloadRequest) androidOnJsBeforeUnload;
+      JsBeforeUnloadRequest jsBeforeUnloadRequest)? androidOnJsBeforeUnload;
 
   @override
   final void Function(
-          InAppWebViewController controller, LoginRequest loginRequest)
+          InAppWebViewController controller, LoginRequest loginRequest)?
       androidOnReceivedLoginRequest;
 }
 
 class _InAppWebViewState extends State<InAppWebView> {
-  InAppWebViewController _controller;
+  late InAppWebViewController _controller;
 
   @override
   Widget build(BuildContext context) {
@@ -348,7 +348,7 @@ class _InAppWebViewState extends State<InAppWebView> {
               PlatformViewController controller,
               ) {
             return AndroidViewSurface(
-              controller: controller,
+              controller: controller as AndroidViewController,
               gestureRecognizers: widget.gestureRecognizers ?? const <Factory<OneSequenceGestureRecognizer>>{},
               hitTestBehavior: PlatformViewHitTestBehavior.opaque,
             );
@@ -359,7 +359,7 @@ class _InAppWebViewState extends State<InAppWebView> {
               viewType: 'com.pichillilorenzo/flutter_inappwebview',
               layoutDirection: TextDirection.rtl,
               creationParams: <String, dynamic>{
-                'initialUrl': '${Uri.parse(widget.initialUrl)}',
+                'initialUrl': widget.initialUrl != null ? '${Uri.parse(widget.initialUrl!)}' : '',
                 'initialFile': widget.initialFile,
                 'initialData': widget.initialData?.toMap(),
                 'initialHeaders': widget.initialHeaders,
@@ -381,7 +381,7 @@ class _InAppWebViewState extends State<InAppWebView> {
           gestureRecognizers: widget.gestureRecognizers,
           layoutDirection: TextDirection.rtl,
           creationParams: <String, dynamic>{
-            'initialUrl': '${Uri.parse(widget.initialUrl)}',
+            'initialUrl': widget.initialUrl != null ? '${Uri.parse(widget.initialUrl!)}' : '',
             'initialFile': widget.initialFile,
             'initialData': widget.initialData?.toMap(),
             'initialHeaders': widget.initialHeaders,
@@ -398,7 +398,7 @@ class _InAppWebViewState extends State<InAppWebView> {
         onPlatformViewCreated: _onPlatformViewCreated,
         gestureRecognizers: widget.gestureRecognizers,
         creationParams: <String, dynamic>{
-          'initialUrl': '${Uri.parse(widget.initialUrl)}',
+          'initialUrl': widget.initialUrl != null ? '${Uri.parse(widget.initialUrl!)}' : '',
           'initialFile': widget.initialFile,
           'initialData': widget.initialData?.toMap(),
           'initialHeaders': widget.initialHeaders,
@@ -426,7 +426,7 @@ class _InAppWebViewState extends State<InAppWebView> {
   void _onPlatformViewCreated(int id) {
     _controller = InAppWebViewController(id, widget);
     if (widget.onWebViewCreated != null) {
-      widget.onWebViewCreated(_controller);
+      widget.onWebViewCreated!(_controller);
     }
   }
 }
diff --git a/lib/src/in_app_webview_controller.dart b/lib/src/in_app_webview_controller.dart
index b2ae8edf..de2c00f8 100644
--- a/lib/src/in_app_webview_controller.dart
+++ b/lib/src/in_app_webview_controller.dart
@@ -39,8 +39,8 @@ const javaScriptHandlerForbiddenNames = [
 ///If you are using the [InAppWebView] widget, an [InAppWebViewController] instance can be obtained by setting the [InAppWebView.onWebViewCreated]
 ///callback. Instead, if you are using an [InAppBrowser] instance, you can get it through the [InAppBrowser.webViewController] attribute.
 class InAppWebViewController {
-  WebView _webview;
-  MethodChannel _channel;
+  WebView? _webview;
+  late MethodChannel _channel;
   static MethodChannel _staticChannel =
       MethodChannel('com.pichillilorenzo/flutter_inappwebview_static');
   Map<String, JavaScriptHandlerCallback> javaScriptHandlersMap =
@@ -53,18 +53,18 @@ class InAppWebViewController {
   dynamic _id;
 
   // ignore: unused_field
-  String _inAppBrowserUuid;
+  String? _inAppBrowserUuid;
 
-  InAppBrowser _inAppBrowser;
+  InAppBrowser? _inAppBrowser;
 
   ///Android controller that contains only android-specific methods
-  AndroidInAppWebViewController android;
+  late AndroidInAppWebViewController android;
 
   ///iOS controller that contains only ios-specific methods
-  IOSInAppWebViewController ios;
+  late IOSInAppWebViewController ios;
 
   ///Provides access to the JavaScript [Web Storage API](https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API): `window.sessionStorage` and `window.localStorage`.
-  WebStorage webStorage;
+  late WebStorage webStorage;
 
   InAppWebViewController(dynamic id, WebView webview) {
     this._id = id;
@@ -72,10 +72,7 @@ class InAppWebViewController {
         MethodChannel('com.pichillilorenzo/flutter_inappwebview_$id');
     this._channel.setMethodCallHandler(handleMethod);
     this._webview = webview;
-    this.android = AndroidInAppWebViewController(this);
-    this.ios = IOSInAppWebViewController(this);
-    this.webStorage = WebStorage(
-        localStorage: LocalStorage(this), sessionStorage: SessionStorage(this));
+    this._init();
   }
 
   InAppWebViewController.fromInAppBrowser(
@@ -83,60 +80,68 @@ class InAppWebViewController {
     this._inAppBrowserUuid = uuid;
     this._channel = channel;
     this._inAppBrowser = inAppBrowser;
+    this._init();
+  }
+
+  void _init() {
+    this.android = AndroidInAppWebViewController(this);
+    this.ios = IOSInAppWebViewController(this);
+    this.webStorage = WebStorage(
+        localStorage: LocalStorage(this), sessionStorage: SessionStorage(this));
   }
 
   Future<dynamic> handleMethod(MethodCall call) async {
     switch (call.method) {
       case "onHeadlessWebViewCreated":
-        if (_webview != null && _webview is HeadlessInAppWebView)
-          _webview.onWebViewCreated(this);
+        if (_webview != null && _webview is HeadlessInAppWebView && _webview!.onWebViewCreated != null)
+          _webview!.onWebViewCreated!(this);
         break;
       case "onLoadStart":
-        String url = call.arguments["url"];
-        if (_webview != null && _webview.onLoadStart != null)
-          _webview.onLoadStart(this, url);
-        else if (_inAppBrowser != null) _inAppBrowser.onLoadStart(url);
+        String? url = call.arguments["url"];
+        if (_webview != null && _webview!.onLoadStart != null)
+          _webview!.onLoadStart!(this, url);
+        else if (_inAppBrowser != null) _inAppBrowser!.onLoadStart(url);
         break;
       case "onLoadStop":
-        String url = call.arguments["url"];
-        if (_webview != null && _webview.onLoadStop != null)
-          _webview.onLoadStop(this, url);
-        else if (_inAppBrowser != null) _inAppBrowser.onLoadStop(url);
+        String? url = call.arguments["url"];
+        if (_webview != null && _webview!.onLoadStop != null)
+          _webview!.onLoadStop!(this, url);
+        else if (_inAppBrowser != null) _inAppBrowser!.onLoadStop(url);
         break;
       case "onLoadError":
-        String url = call.arguments["url"];
+        String? url = call.arguments["url"];
         int code = call.arguments["code"];
         String message = call.arguments["message"];
-        if (_webview != null && _webview.onLoadError != null)
-          _webview.onLoadError(this, url, code, message);
+        if (_webview != null && _webview!.onLoadError != null)
+          _webview!.onLoadError!(this, url, code, message);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onLoadError(url, code, message);
+          _inAppBrowser!.onLoadError(url, code, message);
         break;
       case "onLoadHttpError":
-        String url = call.arguments["url"];
+        String? url = call.arguments["url"];
         int statusCode = call.arguments["statusCode"];
         String description = call.arguments["description"];
-        if (_webview != null && _webview.onLoadHttpError != null)
-          _webview.onLoadHttpError(this, url, statusCode, description);
+        if (_webview != null && _webview!.onLoadHttpError != null)
+          _webview!.onLoadHttpError!(this, url, statusCode, description);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onLoadHttpError(url, statusCode, description);
+          _inAppBrowser!.onLoadHttpError(url, statusCode, description);
         break;
       case "onProgressChanged":
         int progress = call.arguments["progress"];
-        if (_webview != null && _webview.onProgressChanged != null)
-          _webview.onProgressChanged(this, progress);
+        if (_webview != null && _webview!.onProgressChanged != null)
+          _webview!.onProgressChanged!(this, progress);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onProgressChanged(progress);
+          _inAppBrowser!.onProgressChanged(progress);
         break;
       case "shouldOverrideUrlLoading":
         String url = call.arguments["url"];
-        String method = call.arguments["method"];
-        Map<String, String> headers =
+        String? method = call.arguments["method"];
+        Map<String, String>? headers =
             call.arguments["headers"]?.cast<String, String>();
         bool isForMainFrame = call.arguments["isForMainFrame"];
-        bool androidHasGesture = call.arguments["androidHasGesture"];
-        bool androidIsRedirect = call.arguments["androidIsRedirect"];
-        int iosWKNavigationType = call.arguments["iosWKNavigationType"];
+        bool? androidHasGesture = call.arguments["androidHasGesture"];
+        bool? androidIsRedirect = call.arguments["androidIsRedirect"];
+        int? iosWKNavigationType = call.arguments["iosWKNavigationType"];
 
         ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest =
             ShouldOverrideUrlLoadingRequest(
@@ -149,46 +154,46 @@ class InAppWebViewController {
                 iosWKNavigationType:
                     IOSWKNavigationType.fromValue(iosWKNavigationType));
 
-        if (_webview != null && _webview.shouldOverrideUrlLoading != null)
-          return (await _webview.shouldOverrideUrlLoading(
+        if (_webview != null && _webview!.shouldOverrideUrlLoading != null)
+          return (await _webview!.shouldOverrideUrlLoading!(
                   this, shouldOverrideUrlLoadingRequest))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser
+          return (await _inAppBrowser!
                   .shouldOverrideUrlLoading(shouldOverrideUrlLoadingRequest))
               ?.toMap();
         break;
       case "onConsoleMessage":
         String message = call.arguments["message"];
-        ConsoleMessageLevel messageLevel =
+        ConsoleMessageLevel? messageLevel =
             ConsoleMessageLevel.fromValue(call.arguments["messageLevel"]);
         ConsoleMessage consoleMessage =
             ConsoleMessage(message: message, messageLevel: messageLevel);
-        if (_webview != null && _webview.onConsoleMessage != null)
-          _webview.onConsoleMessage(this, consoleMessage);
+        if (_webview != null && _webview!.onConsoleMessage != null)
+          _webview!.onConsoleMessage!(this, consoleMessage);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onConsoleMessage(consoleMessage);
+          _inAppBrowser!.onConsoleMessage(consoleMessage);
         break;
       case "onScrollChanged":
         int x = call.arguments["x"];
         int y = call.arguments["y"];
-        if (_webview != null && _webview.onScrollChanged != null)
-          _webview.onScrollChanged(this, x, y);
-        else if (_inAppBrowser != null) _inAppBrowser.onScrollChanged(x, y);
+        if (_webview != null && _webview!.onScrollChanged != null)
+          _webview!.onScrollChanged!(this, x, y);
+        else if (_inAppBrowser != null) _inAppBrowser!.onScrollChanged(x, y);
         break;
       case "onDownloadStart":
         String url = call.arguments["url"];
-        if (_webview != null && _webview.onDownloadStart != null)
-          _webview.onDownloadStart(this, url);
-        else if (_inAppBrowser != null) _inAppBrowser.onDownloadStart(url);
+        if (_webview != null && _webview!.onDownloadStart != null)
+          _webview!.onDownloadStart!(this, url);
+        else if (_inAppBrowser != null) _inAppBrowser!.onDownloadStart(url);
         break;
       case "onLoadResourceCustomScheme":
         String scheme = call.arguments["scheme"];
         String url = call.arguments["url"];
-        if (_webview != null && _webview.onLoadResourceCustomScheme != null) {
+        if (_webview != null && _webview!.onLoadResourceCustomScheme != null) {
           try {
             var response =
-                await _webview.onLoadResourceCustomScheme(this, scheme, url);
+                await _webview!.onLoadResourceCustomScheme!(this, scheme, url);
             return (response != null) ? response.toJson() : null;
           } catch (error) {
             print(error);
@@ -197,7 +202,7 @@ class InAppWebViewController {
         } else if (_inAppBrowser != null) {
           try {
             var response =
-                await _inAppBrowser.onLoadResourceCustomScheme(scheme, url);
+                await _inAppBrowser!.onLoadResourceCustomScheme(scheme, url);
             return (response != null) ? response.toJson() : null;
           } catch (error) {
             print(error);
@@ -206,12 +211,12 @@ class InAppWebViewController {
         }
         break;
       case "onCreateWindow":
-        String url = call.arguments["url"];
+        String? url = call.arguments["url"];
         int windowId = call.arguments["windowId"];
-        bool androidIsDialog = call.arguments["androidIsDialog"];
-        bool androidIsUserGesture = call.arguments["androidIsUserGesture"];
-        int iosWKNavigationType = call.arguments["iosWKNavigationType"];
-        bool iosIsForMainFrame = call.arguments["iosIsForMainFrame"];
+        bool? androidIsDialog = call.arguments["androidIsDialog"];
+        bool? androidIsUserGesture = call.arguments["androidIsUserGesture"];
+        int? iosWKNavigationType = call.arguments["iosWKNavigationType"];
+        bool? iosIsForMainFrame = call.arguments["iosIsForMainFrame"];
 
         CreateWindowRequest createWindowRequest = CreateWindowRequest(
             url: url,
@@ -222,49 +227,49 @@ class InAppWebViewController {
                 IOSWKNavigationType.fromValue(iosWKNavigationType),
             iosIsForMainFrame: iosIsForMainFrame);
 
-        bool result = false;
+        bool? result = false;
 
-        if (_webview != null && _webview.onCreateWindow != null)
-          result = await _webview.onCreateWindow(this, createWindowRequest);
+        if (_webview != null && _webview!.onCreateWindow != null)
+          result = await _webview!.onCreateWindow!(this, createWindowRequest);
         else if (_inAppBrowser != null) {
-          result = await _inAppBrowser.onCreateWindow(createWindowRequest);
+          result = await _inAppBrowser!.onCreateWindow(createWindowRequest);
         }
 
         return result;
       case "onCloseWindow":
-        if (_webview != null && _webview.onCloseWindow != null)
-          _webview.onCloseWindow(this);
-        else if (_inAppBrowser != null) _inAppBrowser.onCloseWindow();
+        if (_webview != null && _webview!.onCloseWindow != null)
+          _webview!.onCloseWindow!(this);
+        else if (_inAppBrowser != null) _inAppBrowser!.onCloseWindow();
         break;
       case "onTitleChanged":
-        String title = call.arguments["title"];
-        if (_webview != null && _webview.onTitleChanged != null)
-          _webview.onTitleChanged(this, title);
-        else if (_inAppBrowser != null) _inAppBrowser.onTitleChanged(title);
+        String? title = call.arguments["title"];
+        if (_webview != null && _webview!.onTitleChanged != null)
+          _webview!.onTitleChanged!(this, title);
+        else if (_inAppBrowser != null) _inAppBrowser!.onTitleChanged(title);
         break;
       case "onGeolocationPermissionsShowPrompt":
         String origin = call.arguments["origin"];
         if (_webview != null &&
-            _webview.androidOnGeolocationPermissionsShowPrompt != null)
-          return (await _webview.androidOnGeolocationPermissionsShowPrompt(
+            _webview!.androidOnGeolocationPermissionsShowPrompt != null)
+          return (await _webview!.androidOnGeolocationPermissionsShowPrompt!(
                   this, origin))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser
+          return (await _inAppBrowser!
                   .androidOnGeolocationPermissionsShowPrompt(origin))
               ?.toMap();
         break;
       case "onGeolocationPermissionsHidePrompt":
         if (_webview != null &&
-            _webview.androidOnGeolocationPermissionsHidePrompt != null)
-          _webview.androidOnGeolocationPermissionsHidePrompt(this);
+            _webview!.androidOnGeolocationPermissionsHidePrompt != null)
+          _webview!.androidOnGeolocationPermissionsHidePrompt!(this);
         else if (_inAppBrowser != null)
-          _inAppBrowser.androidOnGeolocationPermissionsHidePrompt();
+          _inAppBrowser!.androidOnGeolocationPermissionsHidePrompt();
         break;
       case "shouldInterceptRequest":
         String url = call.arguments["url"];
         String method = call.arguments["method"];
-        Map<String, String> headers =
+        Map<String, String>? headers =
             call.arguments["headers"]?.cast<String, String>();
         bool isForMainFrame = call.arguments["isForMainFrame"];
         bool hasGesture = call.arguments["hasGesture"];
@@ -278,112 +283,112 @@ class InAppWebViewController {
             hasGesture: hasGesture,
             isRedirect: isRedirect);
 
-        if (_webview != null && _webview.androidShouldInterceptRequest != null)
-          return (await _webview.androidShouldInterceptRequest(this, request))
+        if (_webview != null && _webview!.androidShouldInterceptRequest != null)
+          return (await _webview!.androidShouldInterceptRequest!(this, request))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.androidShouldInterceptRequest(request))
+          return (await _inAppBrowser!.androidShouldInterceptRequest(request))
               ?.toMap();
         break;
       case "onRenderProcessUnresponsive":
-        String url = call.arguments["url"];
+        String? url = call.arguments["url"];
         if (_webview != null &&
-            _webview.androidOnRenderProcessUnresponsive != null)
-          return (await _webview.androidOnRenderProcessUnresponsive(this, url))
+            _webview!.androidOnRenderProcessUnresponsive != null)
+          return (await _webview!.androidOnRenderProcessUnresponsive!(this, url))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.androidOnRenderProcessUnresponsive(url))
+          return (await _inAppBrowser!.androidOnRenderProcessUnresponsive(url))
               ?.toMap();
         break;
       case "onRenderProcessResponsive":
-        String url = call.arguments["url"];
+        String? url = call.arguments["url"];
         if (_webview != null &&
-            _webview.androidOnRenderProcessResponsive != null)
-          return (await _webview.androidOnRenderProcessResponsive(this, url))
+            _webview!.androidOnRenderProcessResponsive != null)
+          return (await _webview!.androidOnRenderProcessResponsive!(this, url))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.androidOnRenderProcessResponsive(url))
+          return (await _inAppBrowser!.androidOnRenderProcessResponsive(url))
               ?.toMap();
         break;
       case "onRenderProcessGone":
         bool didCrash = call.arguments["didCrash"];
-        RendererPriority rendererPriorityAtExit = RendererPriority.fromValue(
+        RendererPriority? rendererPriorityAtExit = RendererPriority.fromValue(
             call.arguments["rendererPriorityAtExit"]);
         var detail = RenderProcessGoneDetail(
             didCrash: didCrash, rendererPriorityAtExit: rendererPriorityAtExit);
 
-        if (_webview != null && _webview.androidOnRenderProcessGone != null)
-          _webview.androidOnRenderProcessGone(this, detail);
+        if (_webview != null && _webview!.androidOnRenderProcessGone != null)
+          _webview!.androidOnRenderProcessGone!(this, detail);
         else if (_inAppBrowser != null)
-          _inAppBrowser.androidOnRenderProcessGone(detail);
+          _inAppBrowser!.androidOnRenderProcessGone(detail);
         break;
       case "onFormResubmission":
-        String url = call.arguments["url"];
-        if (_webview != null && _webview.androidOnFormResubmission != null)
-          return (await _webview.androidOnFormResubmission(this, url))?.toMap();
+        String? url = call.arguments["url"];
+        if (_webview != null && _webview!.androidOnFormResubmission != null)
+          return (await _webview!.androidOnFormResubmission!(this, url))?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.androidOnFormResubmission(url))?.toMap();
+          return (await _inAppBrowser!.androidOnFormResubmission(url))?.toMap();
         break;
       case "onScaleChanged":
         double oldScale = call.arguments["oldScale"];
         double newScale = call.arguments["newScale"];
-        if (_webview != null && _webview.androidOnScaleChanged != null)
-          _webview.androidOnScaleChanged(this, oldScale, newScale);
+        if (_webview != null && _webview!.androidOnScaleChanged != null)
+          _webview!.androidOnScaleChanged!(this, oldScale, newScale);
         else if (_inAppBrowser != null)
-          _inAppBrowser.androidOnScaleChanged(oldScale, newScale);
+          _inAppBrowser!.androidOnScaleChanged(oldScale, newScale);
         break;
       case "onRequestFocus":
-        if (_webview != null && _webview.androidOnRequestFocus != null)
-          _webview.androidOnRequestFocus(this);
-        else if (_inAppBrowser != null) _inAppBrowser.androidOnRequestFocus();
+        if (_webview != null && _webview!.androidOnRequestFocus != null)
+          _webview!.androidOnRequestFocus!(this);
+        else if (_inAppBrowser != null) _inAppBrowser!.androidOnRequestFocus();
         break;
       case "onReceivedIcon":
         Uint8List icon = Uint8List.fromList(call.arguments["icon"].cast<int>());
 
-        if (_webview != null && _webview.androidOnReceivedIcon != null)
-          _webview.androidOnReceivedIcon(this, icon);
+        if (_webview != null && _webview!.androidOnReceivedIcon != null)
+          _webview!.androidOnReceivedIcon!(this, icon);
         else if (_inAppBrowser != null)
-          _inAppBrowser.androidOnReceivedIcon(icon);
+          _inAppBrowser!.androidOnReceivedIcon(icon);
         break;
       case "onReceivedTouchIconUrl":
         String url = call.arguments["url"];
         bool precomposed = call.arguments["precomposed"];
-        if (_webview != null && _webview.androidOnReceivedTouchIconUrl != null)
-          _webview.androidOnReceivedTouchIconUrl(this, url, precomposed);
+        if (_webview != null && _webview!.androidOnReceivedTouchIconUrl != null)
+          _webview!.androidOnReceivedTouchIconUrl!(this, url, precomposed);
         else if (_inAppBrowser != null)
-          _inAppBrowser.androidOnReceivedTouchIconUrl(url, precomposed);
+          _inAppBrowser!.androidOnReceivedTouchIconUrl(url, precomposed);
         break;
       case "onJsAlert":
-        String url = call.arguments["url"];
-        String message = call.arguments["message"];
-        bool iosIsMainFrame = call.arguments["iosIsMainFrame"];
+        String? url = call.arguments["url"];
+        String? message = call.arguments["message"];
+        bool? iosIsMainFrame = call.arguments["iosIsMainFrame"];
 
         JsAlertRequest jsAlertRequest = JsAlertRequest(
             url: url, message: message, iosIsMainFrame: iosIsMainFrame);
 
-        if (_webview != null && _webview.onJsAlert != null)
-          return (await _webview.onJsAlert(this, jsAlertRequest))?.toMap();
+        if (_webview != null && _webview!.onJsAlert != null)
+          return (await _webview!.onJsAlert!(this, jsAlertRequest))?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.onJsAlert(jsAlertRequest))?.toMap();
+          return (await _inAppBrowser!.onJsAlert(jsAlertRequest))?.toMap();
         break;
       case "onJsConfirm":
-        String url = call.arguments["url"];
-        String message = call.arguments["message"];
-        bool iosIsMainFrame = call.arguments["iosIsMainFrame"];
+        String? url = call.arguments["url"];
+        String? message = call.arguments["message"];
+        bool? iosIsMainFrame = call.arguments["iosIsMainFrame"];
 
         JsConfirmRequest jsConfirmRequest = JsConfirmRequest(
             url: url, message: message, iosIsMainFrame: iosIsMainFrame);
 
-        if (_webview != null && _webview.onJsConfirm != null)
-          return (await _webview.onJsConfirm(this, jsConfirmRequest))?.toMap();
+        if (_webview != null && _webview!.onJsConfirm != null)
+          return (await _webview!.onJsConfirm!(this, jsConfirmRequest))?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.onJsConfirm(jsConfirmRequest))?.toMap();
+          return (await _inAppBrowser!.onJsConfirm(jsConfirmRequest))?.toMap();
         break;
       case "onJsPrompt":
-        String url = call.arguments["url"];
-        String message = call.arguments["message"];
-        String defaultValue = call.arguments["defaultValue"];
-        bool iosIsMainFrame = call.arguments["iosIsMainFrame"];
+        String? url = call.arguments["url"];
+        String? message = call.arguments["message"];
+        String? defaultValue = call.arguments["defaultValue"];
+        bool? iosIsMainFrame = call.arguments["iosIsMainFrame"];
 
         JsPromptRequest jsPromptRequest = JsPromptRequest(
             url: url,
@@ -391,85 +396,85 @@ class InAppWebViewController {
             defaultValue: defaultValue,
             iosIsMainFrame: iosIsMainFrame);
 
-        if (_webview != null && _webview.onJsPrompt != null)
-          return (await _webview.onJsPrompt(this, jsPromptRequest))?.toMap();
+        if (_webview != null && _webview!.onJsPrompt != null)
+          return (await _webview!.onJsPrompt!(this, jsPromptRequest))?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.onJsPrompt(jsPromptRequest))?.toMap();
+          return (await _inAppBrowser!.onJsPrompt(jsPromptRequest))?.toMap();
         break;
       case "onJsBeforeUnload":
-        String url = call.arguments["url"];
-        String message = call.arguments["message"];
-        bool iosIsMainFrame = call.arguments["iosIsMainFrame"];
+        String? url = call.arguments["url"];
+        String? message = call.arguments["message"];
+        bool? iosIsMainFrame = call.arguments["iosIsMainFrame"];
 
         JsBeforeUnloadRequest jsBeforeUnloadRequest = JsBeforeUnloadRequest(
             url: url, message: message, iosIsMainFrame: iosIsMainFrame);
 
         print(jsBeforeUnloadRequest);
 
-        if (_webview != null && _webview.androidOnJsBeforeUnload != null)
-          return (await _webview.androidOnJsBeforeUnload(
+        if (_webview != null && _webview!.androidOnJsBeforeUnload != null)
+          return (await _webview!.androidOnJsBeforeUnload!(
                   this, jsBeforeUnloadRequest))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser
+          return (await _inAppBrowser!
                   .androidOnJsBeforeUnload(jsBeforeUnloadRequest))
               ?.toMap();
         break;
       case "onSafeBrowsingHit":
         String url = call.arguments["url"];
-        SafeBrowsingThreat threatType =
+        SafeBrowsingThreat? threatType =
             SafeBrowsingThreat.fromValue(call.arguments["threatType"]);
-        if (_webview != null && _webview.androidOnSafeBrowsingHit != null)
-          return (await _webview.androidOnSafeBrowsingHit(
+        if (_webview != null && _webview!.androidOnSafeBrowsingHit != null)
+          return (await _webview!.androidOnSafeBrowsingHit!(
                   this, url, threatType))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.androidOnSafeBrowsingHit(url, threatType))
+          return (await _inAppBrowser!.androidOnSafeBrowsingHit(url, threatType))
               ?.toMap();
         break;
       case "onReceivedLoginRequest":
         String realm = call.arguments["realm"];
-        String account = call.arguments["account"];
+        String? account = call.arguments["account"];
         String args = call.arguments["args"];
 
         LoginRequest loginRequest =
             LoginRequest(realm: realm, account: account, args: args);
 
-        if (_webview != null && _webview.androidOnReceivedLoginRequest != null)
-          _webview.androidOnReceivedLoginRequest(this, loginRequest);
+        if (_webview != null && _webview!.androidOnReceivedLoginRequest != null)
+          _webview!.androidOnReceivedLoginRequest!(this, loginRequest);
         else if (_inAppBrowser != null)
-          _inAppBrowser.androidOnReceivedLoginRequest(loginRequest);
+          _inAppBrowser!.androidOnReceivedLoginRequest(loginRequest);
         break;
       case "onReceivedHttpAuthRequest":
         String host = call.arguments["host"];
         String protocol = call.arguments["protocol"];
-        String realm = call.arguments["realm"];
-        int port = call.arguments["port"];
+        String? realm = call.arguments["realm"];
+        int? port = call.arguments["port"];
         int previousFailureCount = call.arguments["previousFailureCount"];
         var protectionSpace = ProtectionSpace(
             host: host, protocol: protocol, realm: realm, port: port);
         var challenge = HttpAuthChallenge(
             previousFailureCount: previousFailureCount,
             protectionSpace: protectionSpace);
-        if (_webview != null && _webview.onReceivedHttpAuthRequest != null)
-          return (await _webview.onReceivedHttpAuthRequest(this, challenge))
+        if (_webview != null && _webview!.onReceivedHttpAuthRequest != null)
+          return (await _webview!.onReceivedHttpAuthRequest!(this, challenge))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.onReceivedHttpAuthRequest(challenge))
+          return (await _inAppBrowser!.onReceivedHttpAuthRequest(challenge))
               ?.toMap();
         break;
       case "onReceivedServerTrustAuthRequest":
         String host = call.arguments["host"];
         String protocol = call.arguments["protocol"];
-        String realm = call.arguments["realm"];
-        int port = call.arguments["port"];
-        int androidError = call.arguments["androidError"];
-        int iosError = call.arguments["iosError"];
-        String message = call.arguments["message"];
-        Map<String, dynamic> sslCertificateMap =
+        String? realm = call.arguments["realm"];
+        int? port = call.arguments["port"];
+        int? androidError = call.arguments["androidError"];
+        int? iosError = call.arguments["iosError"];
+        String? message = call.arguments["message"];
+        Map<String, dynamic>? sslCertificateMap =
             call.arguments["sslCertificate"]?.cast<String, dynamic>();
 
-        SslCertificate sslCertificate;
+        SslCertificate? sslCertificate;
         if (sslCertificateMap != null) {
           if (defaultTargetPlatform == TargetPlatform.iOS) {
             try {
@@ -514,10 +519,10 @@ class InAppWebViewController {
           }
         }
 
-        AndroidSslError androidSslError = androidError != null
+        AndroidSslError? androidSslError = androidError != null
             ? AndroidSslError.fromValue(androidError)
             : null;
-        IOSSslError iosSslError =
+        IOSSslError? iosSslError =
             iosError != null ? IOSSslError.fromValue(iosError) : null;
 
         var protectionSpace = ProtectionSpace(
@@ -529,141 +534,141 @@ class InAppWebViewController {
             message: message,
             sslCertificate: sslCertificate);
         if (_webview != null &&
-            _webview.onReceivedServerTrustAuthRequest != null)
-          return (await _webview.onReceivedServerTrustAuthRequest(
+            _webview!.onReceivedServerTrustAuthRequest != null)
+          return (await _webview!.onReceivedServerTrustAuthRequest!(
                   this, challenge))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser
+          return (await _inAppBrowser!
                   .onReceivedServerTrustAuthRequest(challenge))
               ?.toMap();
         break;
       case "onReceivedClientCertRequest":
         String host = call.arguments["host"];
         String protocol = call.arguments["protocol"];
-        String realm = call.arguments["realm"];
-        int port = call.arguments["port"];
+        String? realm = call.arguments["realm"];
+        int? port = call.arguments["port"];
         var protectionSpace = ProtectionSpace(
             host: host, protocol: protocol, realm: realm, port: port);
         var challenge = ClientCertChallenge(protectionSpace: protectionSpace);
-        if (_webview != null && _webview.onReceivedClientCertRequest != null)
-          return (await _webview.onReceivedClientCertRequest(this, challenge))
+        if (_webview != null && _webview!.onReceivedClientCertRequest != null)
+          return (await _webview!.onReceivedClientCertRequest!(this, challenge))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.onReceivedClientCertRequest(challenge))
+          return (await _inAppBrowser!.onReceivedClientCertRequest(challenge))
               ?.toMap();
         break;
       case "onFindResultReceived":
         int activeMatchOrdinal = call.arguments["activeMatchOrdinal"];
         int numberOfMatches = call.arguments["numberOfMatches"];
         bool isDoneCounting = call.arguments["isDoneCounting"];
-        if (_webview != null && _webview.onFindResultReceived != null)
-          _webview.onFindResultReceived(
+        if (_webview != null && _webview!.onFindResultReceived != null)
+          _webview!.onFindResultReceived!(
               this, activeMatchOrdinal, numberOfMatches, isDoneCounting);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onFindResultReceived(
+          _inAppBrowser!.onFindResultReceived(
               activeMatchOrdinal, numberOfMatches, isDoneCounting);
         break;
       case "onPermissionRequest":
         String origin = call.arguments["origin"];
         List<String> resources = call.arguments["resources"].cast<String>();
-        if (_webview != null && _webview.androidOnPermissionRequest != null)
-          return (await _webview.androidOnPermissionRequest(
+        if (_webview != null && _webview!.androidOnPermissionRequest != null)
+          return (await _webview!.androidOnPermissionRequest!(
                   this, origin, resources))
               ?.toMap();
         else if (_inAppBrowser != null)
-          return (await _inAppBrowser.androidOnPermissionRequest(
+          return (await _inAppBrowser!.androidOnPermissionRequest(
                   origin, resources))
               ?.toMap();
         break;
       case "onUpdateVisitedHistory":
-        String url = call.arguments["url"];
-        bool androidIsReload = call.arguments["androidIsReload"];
-        if (_webview != null && _webview.onUpdateVisitedHistory != null)
-          _webview.onUpdateVisitedHistory(this, url, androidIsReload);
+        String? url = call.arguments["url"];
+        bool? androidIsReload = call.arguments["androidIsReload"];
+        if (_webview != null && _webview!.onUpdateVisitedHistory != null)
+          _webview!.onUpdateVisitedHistory!(this, url, androidIsReload);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onUpdateVisitedHistory(url, androidIsReload);
+          _inAppBrowser!.onUpdateVisitedHistory(url, androidIsReload);
         return null;
       case "onWebContentProcessDidTerminate":
         if (_webview != null &&
-            _webview.iosOnWebContentProcessDidTerminate != null)
-          _webview.iosOnWebContentProcessDidTerminate(this);
+            _webview!.iosOnWebContentProcessDidTerminate != null)
+          _webview!.iosOnWebContentProcessDidTerminate!(this);
         else if (_inAppBrowser != null)
-          _inAppBrowser.iosOnWebContentProcessDidTerminate();
+          _inAppBrowser!.iosOnWebContentProcessDidTerminate();
         break;
       case "onPageCommitVisible":
-        String url = call.arguments["url"];
-        if (_webview != null && _webview.onPageCommitVisible != null)
-          _webview.onPageCommitVisible(this, url);
-        else if (_inAppBrowser != null) _inAppBrowser.onPageCommitVisible(url);
+        String? url = call.arguments["url"];
+        if (_webview != null && _webview!.onPageCommitVisible != null)
+          _webview!.onPageCommitVisible!(this, url);
+        else if (_inAppBrowser != null) _inAppBrowser!.onPageCommitVisible(url);
         break;
       case "onDidReceiveServerRedirectForProvisionalNavigation":
         if (_webview != null &&
-            _webview.iosOnDidReceiveServerRedirectForProvisionalNavigation !=
+            _webview!.iosOnDidReceiveServerRedirectForProvisionalNavigation !=
                 null)
-          _webview.iosOnDidReceiveServerRedirectForProvisionalNavigation(this);
+          _webview!.iosOnDidReceiveServerRedirectForProvisionalNavigation!(this);
         else if (_inAppBrowser != null)
-          _inAppBrowser.iosOnDidReceiveServerRedirectForProvisionalNavigation();
+          _inAppBrowser!.iosOnDidReceiveServerRedirectForProvisionalNavigation();
         break;
       case "onLongPressHitTestResult":
-        Map<dynamic, dynamic> hitTestResultMap =
+        Map<dynamic, dynamic>? hitTestResultMap =
             call.arguments["hitTestResult"];
-        InAppWebViewHitTestResultType type =
+        InAppWebViewHitTestResultType? type =
             InAppWebViewHitTestResultType.fromValue(
-                hitTestResultMap["type"].toInt());
-        String extra = hitTestResultMap["extra"];
+                hitTestResultMap?["type"].toInt());
+        String? extra = hitTestResultMap?["extra"];
         InAppWebViewHitTestResult hitTestResult =
             InAppWebViewHitTestResult(type: type, extra: extra);
 
-        if (_webview != null && _webview.onLongPressHitTestResult != null)
-          _webview.onLongPressHitTestResult(this, hitTestResult);
+        if (_webview != null && _webview!.onLongPressHitTestResult != null)
+          _webview!.onLongPressHitTestResult!(this, hitTestResult);
         else if (_inAppBrowser != null)
-          _inAppBrowser.onLongPressHitTestResult(hitTestResult);
+          _inAppBrowser!.onLongPressHitTestResult(hitTestResult);
         break;
       case "onCreateContextMenu":
-        ContextMenu contextMenu;
-        if (_webview != null && _webview.contextMenu != null) {
-          contextMenu = _webview.contextMenu;
-        } else if (_inAppBrowser != null && _inAppBrowser.contextMenu != null) {
-          contextMenu = _inAppBrowser.contextMenu;
+        ContextMenu? contextMenu;
+        if (_webview != null && _webview!.contextMenu != null) {
+          contextMenu = _webview!.contextMenu;
+        } else if (_inAppBrowser != null && _inAppBrowser!.contextMenu != null) {
+          contextMenu = _inAppBrowser!.contextMenu;
         }
 
         if (contextMenu != null && contextMenu.onCreateContextMenu != null) {
-          Map<dynamic, dynamic> hitTestResultMap =
+          Map<dynamic, dynamic>? hitTestResultMap =
               call.arguments["hitTestResult"];
-          InAppWebViewHitTestResultType type =
+          InAppWebViewHitTestResultType? type =
               InAppWebViewHitTestResultType.fromValue(
-                  hitTestResultMap["type"].toInt());
-          String extra = hitTestResultMap["extra"];
+                  hitTestResultMap?["type"].toInt());
+          String? extra = hitTestResultMap?["extra"];
           InAppWebViewHitTestResult hitTestResult =
               InAppWebViewHitTestResult(type: type, extra: extra);
 
-          contextMenu.onCreateContextMenu(hitTestResult);
+          contextMenu.onCreateContextMenu!(hitTestResult);
         }
         break;
       case "onHideContextMenu":
-        ContextMenu contextMenu;
-        if (_webview != null && _webview.contextMenu != null) {
-          contextMenu = _webview.contextMenu;
-        } else if (_inAppBrowser != null && _inAppBrowser.contextMenu != null) {
-          contextMenu = _inAppBrowser.contextMenu;
+        ContextMenu? contextMenu;
+        if (_webview != null && _webview!.contextMenu != null) {
+          contextMenu = _webview!.contextMenu;
+        } else if (_inAppBrowser != null && _inAppBrowser!.contextMenu != null) {
+          contextMenu = _inAppBrowser!.contextMenu;
         }
 
         if (contextMenu != null && contextMenu.onHideContextMenu != null) {
-          contextMenu.onHideContextMenu();
+          contextMenu.onHideContextMenu!();
         }
         break;
       case "onContextMenuActionItemClicked":
-        ContextMenu contextMenu;
-        if (_webview != null && _webview.contextMenu != null) {
-          contextMenu = _webview.contextMenu;
-        } else if (_inAppBrowser != null && _inAppBrowser.contextMenu != null) {
-          contextMenu = _inAppBrowser.contextMenu;
+        ContextMenu? contextMenu;
+        if (_webview != null && _webview!.contextMenu != null) {
+          contextMenu = _webview!.contextMenu;
+        } else if (_inAppBrowser != null && _inAppBrowser!.contextMenu != null) {
+          contextMenu = _inAppBrowser!.contextMenu;
         }
 
         if (contextMenu != null) {
-          int androidId = call.arguments["androidId"];
-          String iosId = call.arguments["iosId"];
+          int? androidId = call.arguments["androidId"];
+          String? iosId = call.arguments["iosId"];
           String title = call.arguments["title"];
 
           ContextMenuItem menuItemClicked = ContextMenuItem(
@@ -673,25 +678,27 @@ class InAppWebViewController {
             if ((defaultTargetPlatform == TargetPlatform.android && menuItem.androidId == androidId) ||
                 (defaultTargetPlatform == TargetPlatform.iOS && menuItem.iosId == iosId)) {
               menuItemClicked = menuItem;
-              menuItem?.action();
+              if (menuItem.action != null) {
+                menuItem.action!();
+              }
               break;
             }
           }
 
           if (contextMenu.onContextMenuActionItemClicked != null) {
-            contextMenu.onContextMenuActionItemClicked(menuItemClicked);
+            contextMenu.onContextMenuActionItemClicked!(menuItemClicked);
           }
         }
         break;
       case "onEnterFullscreen":
-        if (_webview != null && _webview.onEnterFullscreen != null)
-          _webview.onEnterFullscreen(this);
-        else if (_inAppBrowser != null) _inAppBrowser.onEnterFullscreen();
+        if (_webview != null && _webview!.onEnterFullscreen != null)
+          _webview!.onEnterFullscreen!(this);
+        else if (_inAppBrowser != null) _inAppBrowser!.onEnterFullscreen();
         break;
       case "onExitFullscreen":
-        if (_webview != null && _webview.onExitFullscreen != null)
-          _webview.onExitFullscreen(this);
-        else if (_inAppBrowser != null) _inAppBrowser.onExitFullscreen();
+        if (_webview != null && _webview!.onExitFullscreen != null)
+          _webview!.onExitFullscreen!(this);
+        else if (_inAppBrowser != null) _inAppBrowser!.onExitFullscreen();
         break;
       case "onCallJsHandler":
         String handlerName = call.arguments["handlerName"];
@@ -701,12 +708,12 @@ class InAppWebViewController {
         switch (handlerName) {
           case "onLoadResource":
             Map<dynamic, dynamic> argMap = args[0];
-            String initiatorType = argMap["initiatorType"];
-            String url = argMap["name"];
-            double startTime = argMap["startTime"] is int
+            String? initiatorType = argMap["initiatorType"];
+            String? url = argMap["name"];
+            double? startTime = argMap["startTime"] is int
                 ? argMap["startTime"].toDouble()
                 : argMap["startTime"];
-            double duration = argMap["duration"] is int
+            double? duration = argMap["duration"] is int
                 ? argMap["duration"].toDouble()
                 : argMap["duration"];
 
@@ -716,22 +723,22 @@ class InAppWebViewController {
                 startTime: startTime,
                 duration: duration);
 
-            if (_webview != null && _webview.onLoadResource != null)
-              _webview.onLoadResource(this, response);
+            if (_webview != null && _webview!.onLoadResource != null)
+              _webview!.onLoadResource!(this, response);
             else if (_inAppBrowser != null)
-              _inAppBrowser.onLoadResource(response);
+              _inAppBrowser!.onLoadResource(response);
             return null;
           case "shouldInterceptAjaxRequest":
             Map<dynamic, dynamic> argMap = args[0];
             dynamic data = argMap["data"];
-            String method = argMap["method"];
-            String url = argMap["url"];
-            bool isAsync = argMap["isAsync"];
-            String user = argMap["user"];
-            String password = argMap["password"];
-            bool withCredentials = argMap["withCredentials"];
-            AjaxRequestHeaders headers = AjaxRequestHeaders(argMap["headers"]);
-            String responseType = argMap["responseType"];
+            String? method = argMap["method"];
+            String? url = argMap["url"];
+            bool? isAsync = argMap["isAsync"];
+            String? user = argMap["user"];
+            String? password = argMap["password"];
+            bool? withCredentials = argMap["withCredentials"];
+            AjaxRequestHeaders headers = AjaxRequestHeaders(argMap["headers"] ?? {});
+            String? responseType = argMap["responseType"];
 
             var request = new AjaxRequest(
                 data: data,
@@ -744,32 +751,32 @@ class InAppWebViewController {
                 headers: headers,
                 responseType: responseType);
 
-            if (_webview != null && _webview.shouldInterceptAjaxRequest != null)
+            if (_webview != null && _webview!.shouldInterceptAjaxRequest != null)
               return jsonEncode(
-                  await _webview.shouldInterceptAjaxRequest(this, request));
+                  await _webview!.shouldInterceptAjaxRequest!(this, request));
             else if (_inAppBrowser != null)
               return jsonEncode(
-                  await _inAppBrowser.shouldInterceptAjaxRequest(request));
+                  await _inAppBrowser!.shouldInterceptAjaxRequest(request));
             return null;
           case "onAjaxReadyStateChange":
             Map<dynamic, dynamic> argMap = args[0];
             dynamic data = argMap["data"];
-            String method = argMap["method"];
-            String url = argMap["url"];
-            bool isAsync = argMap["isAsync"];
-            String user = argMap["user"];
-            String password = argMap["password"];
-            bool withCredentials = argMap["withCredentials"];
-            AjaxRequestHeaders headers = AjaxRequestHeaders(argMap["headers"]);
-            int readyState = argMap["readyState"];
-            int status = argMap["status"];
-            String responseURL = argMap["responseURL"];
-            String responseType = argMap["responseType"];
+            String? method = argMap["method"];
+            String? url = argMap["url"];
+            bool? isAsync = argMap["isAsync"];
+            String? user = argMap["user"];
+            String? password = argMap["password"];
+            bool? withCredentials = argMap["withCredentials"];
+            AjaxRequestHeaders headers = AjaxRequestHeaders(argMap["headers"] ?? {});
+            int? readyState = argMap["readyState"];
+            int? status = argMap["status"];
+            String? responseURL = argMap["responseURL"];
+            String? responseType = argMap["responseType"];
             dynamic response = argMap["response"];
-            String responseText = argMap["responseText"];
-            String responseXML = argMap["responseXML"];
-            String statusText = argMap["statusText"];
-            Map<dynamic, dynamic> responseHeaders = argMap["responseHeaders"];
+            String? responseText = argMap["responseText"];
+            String? responseXML = argMap["responseXML"];
+            String? statusText = argMap["statusText"];
+            Map<dynamic, dynamic>? responseHeaders = argMap["responseHeaders"];
 
             var request = new AjaxRequest(
                 data: data,
@@ -790,39 +797,39 @@ class InAppWebViewController {
                 statusText: statusText,
                 responseHeaders: responseHeaders);
 
-            if (_webview != null && _webview.onAjaxReadyStateChange != null)
+            if (_webview != null && _webview!.onAjaxReadyStateChange != null)
               return jsonEncode(
-                  await _webview.onAjaxReadyStateChange(this, request));
+                  await _webview!.onAjaxReadyStateChange!(this, request));
             else if (_inAppBrowser != null)
               return jsonEncode(
-                  await _inAppBrowser.onAjaxReadyStateChange(request));
+                  await _inAppBrowser!.onAjaxReadyStateChange(request));
             return null;
           case "onAjaxProgress":
             Map<dynamic, dynamic> argMap = args[0];
             dynamic data = argMap["data"];
-            String method = argMap["method"];
-            String url = argMap["url"];
-            bool isAsync = argMap["isAsync"];
-            String user = argMap["user"];
-            String password = argMap["password"];
-            bool withCredentials = argMap["withCredentials"];
-            AjaxRequestHeaders headers = AjaxRequestHeaders(argMap["headers"]);
-            int readyState = argMap["readyState"];
-            int status = argMap["status"];
-            String responseURL = argMap["responseURL"];
-            String responseType = argMap["responseType"];
+            String? method = argMap["method"];
+            String? url = argMap["url"];
+            bool? isAsync = argMap["isAsync"];
+            String? user = argMap["user"];
+            String? password = argMap["password"];
+            bool? withCredentials = argMap["withCredentials"];
+            AjaxRequestHeaders headers = AjaxRequestHeaders(argMap["headers"] ?? {});
+            int? readyState = argMap["readyState"];
+            int? status = argMap["status"];
+            String? responseURL = argMap["responseURL"];
+            String? responseType = argMap["responseType"];
             dynamic response = argMap["response"];
-            String responseText = argMap["responseText"];
-            String responseXML = argMap["responseXML"];
-            String statusText = argMap["statusText"];
-            Map<dynamic, dynamic> responseHeaders = argMap["responseHeaders"];
-            Map<dynamic, dynamic> eventMap = argMap["event"];
+            String? responseText = argMap["responseText"];
+            String? responseXML = argMap["responseXML"];
+            String? statusText = argMap["statusText"];
+            Map<dynamic, dynamic>? responseHeaders = argMap["responseHeaders"];
+            Map<dynamic, dynamic>? eventMap = argMap["event"];
 
             AjaxRequestEvent event = AjaxRequestEvent(
-                lengthComputable: eventMap["lengthComputable"],
-                loaded: eventMap["loaded"],
-                total: eventMap["total"],
-                type: AjaxRequestEventType.fromValue(eventMap["type"]));
+                lengthComputable: eventMap?["lengthComputable"],
+                loaded: eventMap?["loaded"],
+                total: eventMap?["total"],
+                type: AjaxRequestEventType.fromValue(eventMap?["type"]));
 
             var request = new AjaxRequest(
                 data: data,
@@ -844,31 +851,32 @@ class InAppWebViewController {
                 responseHeaders: responseHeaders,
                 event: event);
 
-            if (_webview != null && _webview.onAjaxProgress != null)
-              return jsonEncode(await _webview.onAjaxProgress(this, request));
+            if (_webview != null && _webview!.onAjaxProgress != null)
+              return jsonEncode(await _webview!.onAjaxProgress!(this, request));
             else if (_inAppBrowser != null)
-              return jsonEncode(await _inAppBrowser.onAjaxProgress(request));
+              return jsonEncode(await _inAppBrowser!.onAjaxProgress(request));
             return null;
           case "shouldInterceptFetchRequest":
             Map<dynamic, dynamic> argMap = args[0];
-            String url = argMap["url"];
-            String method = argMap["method"];
-            Map<dynamic, dynamic> headers = argMap["headers"];
-            Uint8List body = Uint8List.fromList(argMap["body"].cast<int>());
-            String mode = argMap["mode"];
-            FetchRequestCredential credentials =
+            String? url = argMap["url"];
+            String? method = argMap["method"];
+            Map<dynamic, dynamic>? headers = argMap["headers"];
+            headers = headers?.cast<String, dynamic>();
+            Uint8List? body = argMap["body"] != null ? Uint8List.fromList(argMap["body"].cast<int>()) : null;
+            String? mode = argMap["mode"];
+            FetchRequestCredential? credentials =
                 FetchRequest.fromMap(argMap["credentials"]);
-            String cache = argMap["cache"];
-            String redirect = argMap["redirect"];
-            String referrer = argMap["referrer"];
-            String referrerPolicy = argMap["referrerPolicy"];
-            String integrity = argMap["integrity"];
-            bool keepalive = argMap["keepalive"];
+            String? cache = argMap["cache"];
+            String? redirect = argMap["redirect"];
+            String? referrer = argMap["referrer"];
+            String? referrerPolicy = argMap["referrerPolicy"];
+            String? integrity = argMap["integrity"];
+            bool? keepalive = argMap["keepalive"];
 
             var request = new FetchRequest(
                 url: url,
                 method: method,
-                headers: headers,
+                headers: headers as Map<String, dynamic>?,
                 body: body,
                 mode: mode,
                 credentials: credentials,
@@ -880,35 +888,35 @@ class InAppWebViewController {
                 keepalive: keepalive);
 
             if (_webview != null &&
-                _webview.shouldInterceptFetchRequest != null)
+                _webview!.shouldInterceptFetchRequest != null)
               return jsonEncode(
-                  await _webview.shouldInterceptFetchRequest(this, request));
+                  await _webview!.shouldInterceptFetchRequest!(this, request));
             else if (_inAppBrowser != null)
               return jsonEncode(
-                  await _inAppBrowser.shouldInterceptFetchRequest(request));
+                  await _inAppBrowser!.shouldInterceptFetchRequest(request));
             return null;
           case "onPrint":
-            String url = args[0];
-            if (_webview != null && _webview.onPrint != null)
-              _webview.onPrint(this, url);
-            else if (_inAppBrowser != null) _inAppBrowser.onPrint(url);
+            String? url = args[0];
+            if (_webview != null && _webview!.onPrint != null)
+              _webview!.onPrint!(this, url);
+            else if (_inAppBrowser != null) _inAppBrowser!.onPrint(url);
             return null;
           case "onWindowFocus":
-            if (_webview != null && _webview.onWindowFocus != null)
-              _webview.onWindowFocus(this);
-            else if (_inAppBrowser != null) _inAppBrowser.onWindowFocus();
+            if (_webview != null && _webview!.onWindowFocus != null)
+              _webview!.onWindowFocus!(this);
+            else if (_inAppBrowser != null) _inAppBrowser!.onWindowFocus();
             return null;
           case "onWindowBlur":
-            if (_webview != null && _webview.onWindowBlur != null)
-              _webview.onWindowBlur(this);
-            else if (_inAppBrowser != null) _inAppBrowser.onWindowBlur();
+            if (_webview != null && _webview!.onWindowBlur != null)
+              _webview!.onWindowBlur!(this);
+            else if (_inAppBrowser != null) _inAppBrowser!.onWindowBlur();
             return null;
         }
 
         if (javaScriptHandlersMap.containsKey(handlerName)) {
           // convert result to json
           try {
-            return jsonEncode(await javaScriptHandlersMap[handlerName](args));
+            return jsonEncode(await javaScriptHandlersMap[handlerName]!(args));
           } catch (error) {
             print(error);
             return null;
@@ -926,7 +934,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getUrl()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1415005-url
-  Future<String> getUrl() async {
+  Future<String?> getUrl() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getUrl', args);
   }
@@ -936,7 +944,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getTitle()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1415015-title
-  Future<String> getTitle() async {
+  Future<String?> getTitle() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getTitle', args);
   }
@@ -946,7 +954,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getProgress()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1415007-estimatedprogress
-  Future<int> getProgress() async {
+  Future<int?> getProgress() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getProgress', args);
   }
@@ -957,17 +965,22 @@ class InAppWebViewController {
   ///- downloading it using an `HttpClient` through the WebView's current url.
   ///
   ///Returns `null` if it was unable to get it.
-  Future<String> getHtml() async {
-    String html;
+  Future<String?> getHtml() async {
+    String? html;
 
-    InAppWebViewGroupOptions options = await getOptions();
-    if (options != null && options.crossPlatform.javaScriptEnabled == true) {
+    InAppWebViewGroupOptions? options = await getOptions();
+    if (options != null && options.crossPlatform != null &&
+        options.crossPlatform!.javaScriptEnabled == true) {
       html = await evaluateJavascript(
           source: "window.document.getElementsByTagName('html')[0].outerHTML;");
       if (html != null && html.isNotEmpty) return html;
     }
 
     var webviewUrl = await getUrl();
+    if (webviewUrl == null) {
+      return html;
+    }
+
     if (webviewUrl.startsWith("file:///")) {
       var assetPathSplitted = webviewUrl.split("/flutter_assets/");
       var assetPath = assetPathSplitted[assetPathSplitted.length - 1];
@@ -981,11 +994,12 @@ class InAppWebViewController {
       try {
         var htmlRequest = await client.getUrl(url);
         html =
-            await (await htmlRequest.close()).transform(Utf8Decoder()).join();
+        await (await htmlRequest.close()).transform(Utf8Decoder()).join();
       } catch (e) {
         print(e);
       }
     }
+
     return html;
   }
 
@@ -995,13 +1009,18 @@ class InAppWebViewController {
 
     HttpClient client = new HttpClient();
     var webviewUrl = await getUrl();
+
+    if (webviewUrl == null) {
+      return favicons;
+    }
+
     var url = (webviewUrl.startsWith("file:///"))
         ? Uri.file(webviewUrl)
         : Uri.parse(webviewUrl);
-    String manifestUrl;
+    String? manifestUrl;
 
     var html = await getHtml();
-    if (html == null || (html != null && html.isEmpty)) {
+    if (html == null || html.isEmpty) {
       return favicons;
     }
     var assetPathBase;
@@ -1011,8 +1030,9 @@ class InAppWebViewController {
       assetPathBase = assetPathSplitted[0] + "/flutter_assets/";
     }
 
-    InAppWebViewGroupOptions options = await getOptions();
-    if (options != null && options.crossPlatform.javaScriptEnabled == true) {
+    InAppWebViewGroupOptions? options = await getOptions();
+    if (options != null && options.crossPlatform != null &&
+        options.crossPlatform!.javaScriptEnabled == true) {
       List<Map<dynamic, dynamic>> links = (await evaluateJavascript(source: """
 (function() {
   var linkNodes = document.head.getElementsByTagName("link");
@@ -1043,7 +1063,7 @@ class InAppWebViewController {
       for (var link in links) {
         if (link["rel"] == "manifest") {
           manifestUrl = link["href"];
-          if (!_isUrlAbsolute(manifestUrl)) {
+          if (!_isUrlAbsolute(manifestUrl!)) {
             if (manifestUrl.startsWith("/")) {
               manifestUrl = manifestUrl.substring(1);
             }
@@ -1070,8 +1090,8 @@ class InAppWebViewController {
     }
 
     // try to get the manifest file
-    HttpClientRequest manifestRequest;
-    HttpClientResponse manifestResponse;
+    HttpClientRequest? manifestRequest;
+    HttpClientResponse? manifestResponse;
     bool manifestFound = false;
     if (manifestUrl == null) {
       manifestUrl = url.scheme + "://" + url.host + "/manifest.json";
@@ -1088,7 +1108,7 @@ class InAppWebViewController {
 
     if (manifestFound) {
       Map<String, dynamic> manifest =
-          json.decode(await manifestResponse.transform(Utf8Decoder()).join());
+          json.decode(await manifestResponse!.transform(Utf8Decoder()).join());
       if (manifest.containsKey("icons")) {
         for (Map<String, dynamic> icon in manifest["icons"]) {
           favicons.addAll(_createFavicons(url, assetPathBase, icon["src"],
@@ -1104,8 +1124,8 @@ class InAppWebViewController {
     return url.startsWith("http://") || url.startsWith("https://");
   }
 
-  List<Favicon> _createFavicons(Uri url, String assetPathBase, String urlIcon,
-      String rel, String sizes, bool isManifest) {
+  List<Favicon> _createFavicons(Uri url, String? assetPathBase, String urlIcon,
+      String? rel, String? sizes, bool isManifest) {
     List<Favicon> favicons = [];
 
     List<String> urlSplitted = urlIcon.split("/");
@@ -1147,8 +1167,8 @@ class InAppWebViewController {
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1414954-load
   Future<void> loadUrl(
-      {@required String url, Map<String, String> headers = const {}}) async {
-    assert(url != null && url.isNotEmpty);
+      {required String url, Map<String, String> headers = const {}}) async {
+    assert(url.isNotEmpty);
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
     args.putIfAbsent('headers', () => headers);
@@ -1159,9 +1179,8 @@ class InAppWebViewController {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#postUrl(java.lang.String,%20byte[])
   Future<void> postUrl(
-      {@required String url, @required Uint8List postData}) async {
-    assert(url != null && url.isNotEmpty);
-    assert(postData != null);
+      {required String url, required Uint8List postData}) async {
+    assert(url.isNotEmpty);
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => url);
     args.putIfAbsent('postData', () => postData);
@@ -1182,15 +1201,11 @@ class InAppWebViewController {
   ///- https://developer.apple.com/documentation/webkit/wkwebview/1415004-loadhtmlstring
   ///- https://developer.apple.com/documentation/webkit/wkwebview/1415011-load
   Future<void> loadData(
-      {@required String data,
+      {required String data,
       String mimeType = "text/html",
       String encoding = "utf8",
       String baseUrl = "about:blank",
       String androidHistoryUrl = "about:blank"}) async {
-    assert(data != null &&
-        mimeType != null &&
-        encoding != null &&
-        baseUrl != null);
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('data', () => data);
     args.putIfAbsent('mimeType', () => mimeType);
@@ -1230,9 +1245,9 @@ class InAppWebViewController {
   ///...
   ///```
   Future<void> loadFile(
-      {@required String assetFilePath,
+      {required String assetFilePath,
       Map<String, String> headers = const {}}) async {
-    assert(assetFilePath != null && assetFilePath.isNotEmpty);
+    assert(assetFilePath.isNotEmpty);
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('url', () => assetFilePath);
     args.putIfAbsent('headers', () => headers);
@@ -1294,9 +1309,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#goBackOrForward(int)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1414991-go
-  Future<void> goBackOrForward({@required int steps}) async {
-    assert(steps != null);
-
+  Future<void> goBackOrForward({required int steps}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('steps', () => steps);
     await _channel.invokeMethod('goBackOrForward', args);
@@ -1305,17 +1318,17 @@ class InAppWebViewController {
   ///Returns a boolean value indicating whether the WebView can go back or forward the given number of steps. Steps is negative if backward and positive if forward.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#canGoBackOrForward(int)
-  Future<bool> canGoBackOrForward({@required int steps}) async {
-    assert(steps != null);
-
+  Future<bool> canGoBackOrForward({required int steps}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('steps', () => steps);
     return await _channel.invokeMethod('canGoBackOrForward', args);
   }
 
   ///Navigates to a [WebHistoryItem] from the back-forward [WebHistory.list] and sets it as the current item.
-  Future<void> goTo({@required WebHistoryItem historyItem}) async {
-    await goBackOrForward(steps: historyItem.offset);
+  Future<void> goTo({required WebHistoryItem historyItem}) async {
+    if (historyItem.offset != null) {
+      await goBackOrForward(steps: historyItem.offset!);
+    }
   }
 
   ///Check if the WebView instance is in a loading state.
@@ -1344,7 +1357,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#evaluateJavascript(java.lang.String,%20android.webkit.ValueCallback%3Cjava.lang.String%3E)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1415017-evaluatejavascript
-  Future<dynamic> evaluateJavascript({@required String source}) async {
+  Future<dynamic> evaluateJavascript({required String source}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('source', () => source);
     var data = await _channel.invokeMethod('evaluateJavascript', args);
@@ -1358,7 +1371,7 @@ class InAppWebViewController {
   ///because, in these events, the [WebView] is not ready to handle it yet.
   ///Instead, you should call this method, for example, inside the [WebView.onLoadStop] event or in any other events
   ///where you know the page is ready "enough".
-  Future<void> injectJavascriptFileFromUrl({@required String urlFile}) async {
+  Future<void> injectJavascriptFileFromUrl({required String urlFile}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('urlFile', () => urlFile);
     await _channel.invokeMethod('injectJavascriptFileFromUrl', args);
@@ -1371,7 +1384,7 @@ class InAppWebViewController {
   ///Instead, you should call this method, for example, inside the [WebView.onLoadStop] event or in any other events
   ///where you know the page is ready "enough".
   Future<void> injectJavascriptFileFromAsset(
-      {@required String assetFilePath}) async {
+      {required String assetFilePath}) async {
     String source = await rootBundle.loadString(assetFilePath);
     await evaluateJavascript(source: source);
   }
@@ -1382,7 +1395,7 @@ class InAppWebViewController {
   ///because, in these events, the [WebView] is not ready to handle it yet.
   ///Instead, you should call this method, for example, inside the [WebView.onLoadStop] event or in any other events
   ///where you know the page is ready "enough".
-  Future<void> injectCSSCode({@required String source}) async {
+  Future<void> injectCSSCode({required String source}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('source', () => source);
     await _channel.invokeMethod('injectCSSCode', args);
@@ -1394,7 +1407,7 @@ class InAppWebViewController {
   ///because, in these events, the [WebView] is not ready to handle it yet.
   ///Instead, you should call this method, for example, inside the [WebView.onLoadStop] event or in any other events
   ///where you know the page is ready "enough".
-  Future<void> injectCSSFileFromUrl({@required String urlFile}) async {
+  Future<void> injectCSSFileFromUrl({required String urlFile}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('urlFile', () => urlFile);
     await _channel.invokeMethod('injectStyleFile', args);
@@ -1406,7 +1419,7 @@ class InAppWebViewController {
   ///because, in these events, the [WebView] is not ready to handle it yet.
   ///Instead, you should call this method, for example, inside the [WebView.onLoadStop] event or in any other events
   ///where you know the page is ready "enough".
-  Future<void> injectCSSFileFromAsset({@required String assetFilePath}) async {
+  Future<void> injectCSSFileFromAsset({required String assetFilePath}) async {
     String source = await rootBundle.loadString(assetFilePath);
     await injectCSSCode(source: source);
   }
@@ -1462,8 +1475,8 @@ class InAppWebViewController {
   ///before you know that your JavaScript code will call the `window.flutter_inappwebview.callHandler` method,
   ///otherwise you won't be able to intercept the JavaScript message.
   void addJavaScriptHandler(
-      {@required String handlerName,
-      @required JavaScriptHandlerCallback callback}) {
+      {required String handlerName,
+      required JavaScriptHandlerCallback callback}) {
     assert(!javaScriptHandlerForbiddenNames.contains(handlerName));
     this.javaScriptHandlersMap[handlerName] = (callback);
   }
@@ -1471,8 +1484,8 @@ class InAppWebViewController {
   ///Removes a JavaScript message handler previously added with the [addJavaScriptHandler()] associated to [handlerName] key.
   ///Returns the value associated with [handlerName] before it was removed.
   ///Returns `null` if [handlerName] was not found.
-  JavaScriptHandlerCallback removeJavaScriptHandler(
-      {@required String handlerName}) {
+  JavaScriptHandlerCallback? removeJavaScriptHandler(
+      {required String handlerName}) {
     return this.javaScriptHandlersMap.remove(handlerName);
   }
 
@@ -1481,28 +1494,28 @@ class InAppWebViewController {
   ///**NOTE for iOS**: available from iOS 11.0+.
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/2873260-takesnapshot
-  Future<Uint8List> takeScreenshot() async {
+  Future<Uint8List?> takeScreenshot() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('takeScreenshot', args);
   }
 
   ///Sets the WebView options with the new [options] and evaluates them.
-  Future<void> setOptions({@required InAppWebViewGroupOptions options}) async {
+  Future<void> setOptions({required InAppWebViewGroupOptions options}) async {
     Map<String, dynamic> args = <String, dynamic>{};
 
-    args.putIfAbsent('options', () => options?.toMap());
+    args.putIfAbsent('options', () => options.toMap());
     await _channel.invokeMethod('setOptions', args);
   }
 
   ///Gets the current WebView options. Returns `null` if it wasn't able to get them.
-  Future<InAppWebViewGroupOptions> getOptions() async {
+  Future<InAppWebViewGroupOptions?> getOptions() async {
     Map<String, dynamic> args = <String, dynamic>{};
 
-    Map<dynamic, dynamic> options =
+    Map<dynamic, dynamic>? options =
         await _channel.invokeMethod('getOptions', args);
     if (options != null) {
       options = options.cast<String, dynamic>();
-      return InAppWebViewGroupOptions.fromMap(options);
+      return InAppWebViewGroupOptions.fromMap(options as Map<String, dynamic>);
     }
 
     return null;
@@ -1516,10 +1529,15 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#copyBackForwardList()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkwebview/1414977-backforwardlist
-  Future<WebHistory> getCopyBackForwardList() async {
+  Future<WebHistory?> getCopyBackForwardList() async {
     Map<String, dynamic> args = <String, dynamic>{};
-    Map<dynamic, dynamic> result =
+    Map<dynamic, dynamic>? result =
         await _channel.invokeMethod('getCopyBackForwardList', args);
+
+    if (result == null) {
+      return null;
+    }
+
     result = result.cast<String, dynamic>();
 
     List<dynamic> historyListMap = result["history"];
@@ -1527,7 +1545,7 @@ class InAppWebViewController {
 
     int currentIndex = result["currentIndex"];
 
-    List<WebHistoryItem> historyList = List();
+    List<WebHistoryItem> historyList = [] as List<WebHistoryItem>;
     for (var i = 0; i < historyListMap.length; i++) {
       LinkedHashMap<dynamic, dynamic> historyItem = historyListMap[i];
       historyList.add(WebHistoryItem(
@@ -1555,8 +1573,7 @@ class InAppWebViewController {
   ///**NOTE**: on iOS, this is implemented using CSS and Javascript.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#findAllAsync(java.lang.String)
-  Future<void> findAllAsync({@required String find}) async {
-    assert(find != null);
+  Future<void> findAllAsync({required String find}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('find', () => find);
     await _channel.invokeMethod('findAllAsync', args);
@@ -1569,8 +1586,7 @@ class InAppWebViewController {
   ///**NOTE**: on iOS, this is implemented using CSS and Javascript.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#findNext(boolean)
-  Future<void> findNext({@required bool forward}) async {
-    assert(forward != null);
+  Future<void> findNext({required bool forward}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('forward', () => forward);
     await _channel.invokeMethod('findNext', args);
@@ -1610,12 +1626,11 @@ class InAppWebViewController {
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollview/1619400-setcontentoffset
   Future<void> scrollTo(
-      {@required int x, @required int y, bool animated = false}) async {
-    assert(x != null && y != null);
+      {required int x, required int y, bool animated = false}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('x', () => x);
     args.putIfAbsent('y', () => y);
-    args.putIfAbsent('animated', () => animated ?? false);
+    args.putIfAbsent('animated', () => animated);
     await _channel.invokeMethod('scrollTo', args);
   }
 
@@ -1631,12 +1646,11 @@ class InAppWebViewController {
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollview/1619400-setcontentoffset
   Future<void> scrollBy(
-      {@required int x, @required int y, bool animated = false}) async {
-    assert(x != null && y != null);
+      {required int x, required int y, bool animated = false}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('x', () => x);
     args.putIfAbsent('y', () => y);
-    args.putIfAbsent('animated', () => animated ?? false);
+    args.putIfAbsent('animated', () => animated);
     await _channel.invokeMethod('scrollBy', args);
   }
 
@@ -1678,7 +1692,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getContentHeight()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollview/1619399-contentsize
-  Future<int> getContentHeight() async {
+  Future<int?> getContentHeight() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getContentHeight', args);
   }
@@ -1708,7 +1722,7 @@ class InAppWebViewController {
   ///- https://developer.android.com/reference/android/webkit/WebViewClient#onScaleChanged(android.webkit.WebView,%20float,%20float)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollview/1619419-zoomscale
-  Future<double> getScale() async {
+  Future<double?> getScale() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getScale', args);
   }
@@ -1717,7 +1731,7 @@ class InAppWebViewController {
   ///
   ///**NOTE**: This method is implemented with using JavaScript.
   ///Available only on Android 19+.
-  Future<String> getSelectedText() async {
+  Future<String?> getSelectedText() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getSelectedText', args);
   }
@@ -1727,11 +1741,18 @@ class InAppWebViewController {
   ///**NOTE**: On iOS it is implemented using JavaScript.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getHitTestResult()
-  Future<InAppWebViewHitTestResult> getHitTestResult() async {
+  Future<InAppWebViewHitTestResult?> getHitTestResult() async {
     Map<String, dynamic> args = <String, dynamic>{};
-    var hitTestResultMap =
+    Map<dynamic, dynamic>? hitTestResultMap =
         await _channel.invokeMethod('getHitTestResult', args);
-    InAppWebViewHitTestResultType type =
+
+    if (hitTestResultMap == null) {
+      return null;
+    }
+
+    hitTestResultMap = hitTestResultMap.cast<String, dynamic>();
+
+    InAppWebViewHitTestResultType? type =
         InAppWebViewHitTestResultType.fromValue(
             hitTestResultMap["type"].toInt());
     String extra = hitTestResultMap["extra"];
@@ -1749,7 +1770,7 @@ class InAppWebViewController {
   }
 
   ///Sets or updates the WebView context menu to be used next time it will appear.
-  Future<void> setContextMenu(ContextMenu contextMenu) async {
+  Future<void> setContextMenu(ContextMenu? contextMenu) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("contextMenu", () => contextMenu?.toMap());
     await _channel.invokeMethod('setContextMenu', args);
@@ -1761,9 +1782,9 @@ class InAppWebViewController {
   ///**NOTE**: On iOS it is implemented using JavaScript.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#requestFocusNodeHref(android.os.Message)
-  Future<RequestFocusNodeHrefResult> requestFocusNodeHref() async {
+  Future<RequestFocusNodeHrefResult?> requestFocusNodeHref() async {
     Map<String, dynamic> args = <String, dynamic>{};
-    Map<dynamic, dynamic> result =
+    Map<dynamic, dynamic>? result =
         await _channel.invokeMethod('requestFocusNodeHref', args);
     return result != null
         ? RequestFocusNodeHrefResult(
@@ -1779,9 +1800,9 @@ class InAppWebViewController {
   ///**NOTE**: On iOS it is implemented using JavaScript.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#requestImageRef(android.os.Message)
-  Future<RequestImageRefResult> requestImageRef() async {
+  Future<RequestImageRefResult?> requestImageRef() async {
     Map<String, dynamic> args = <String, dynamic>{};
-    Map<dynamic, dynamic> result =
+    Map<dynamic, dynamic>? result =
         await _channel.invokeMethod('requestImageRef', args);
     return result != null
         ? RequestImageRefResult(
@@ -1796,7 +1817,7 @@ class InAppWebViewController {
   Future<List<MetaTag>> getMetaTags() async {
     List<MetaTag> metaTags = [];
 
-    List<Map<dynamic, dynamic>> metaTagList =
+    List<Map<dynamic, dynamic>>? metaTagList =
         (await evaluateJavascript(source: """
 (function() {
   var metaTags = [];
@@ -1856,9 +1877,9 @@ class InAppWebViewController {
   ///`<meta name="theme-color" content="">` tag of the current WebView, if available, otherwise `null`.
   ///
   ///**NOTE**: It is implemented using JavaScript.
-  Future<Color> getMetaThemeColor() async {
+  Future<Color?> getMetaThemeColor() async {
     var metaTags = await getMetaTags();
-    MetaTag metaTagThemeColor;
+    MetaTag? metaTagThemeColor;
 
     for (var metaTag in metaTags) {
       if (metaTag.name == "theme-color") {
@@ -1873,7 +1894,7 @@ class InAppWebViewController {
 
     var colorValue = metaTagThemeColor.content;
 
-    return Util.convertColorFromStringRepresentation(colorValue);
+    return colorValue != null ? Util.convertColorFromStringRepresentation(colorValue) : null;
   }
 
   ///Returns the scrolled left position of the current WebView.
@@ -1881,7 +1902,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/view/View#getScrollX()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollview/1619404-contentoffset
-  Future<int> getScrollX() async {
+  Future<int?> getScrollX() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getScrollX', args);
   }
@@ -1891,7 +1912,7 @@ class InAppWebViewController {
   ///**Official Android API**: https://developer.android.com/reference/android/view/View#getScrollY()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollview/1619404-contentoffset
-  Future<int> getScrollY() async {
+  Future<int?> getScrollY() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _channel.invokeMethod('getScrollY', args);
   }
@@ -1899,10 +1920,10 @@ class InAppWebViewController {
   ///Gets the SSL certificate for the main top-level page or null if there is no certificate (the site is not secure).
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getCertificate()
-  Future<SslCertificate> getCertificate() async {
+  Future<SslCertificate?> getCertificate() async {
     Map<String, dynamic> args = <String, dynamic>{};
 
-    Map<String, dynamic> sslCertificateMap =
+    Map<String, dynamic>? sslCertificateMap =
         (await _channel.invokeMethod('getCertificate', args))
             ?.cast<String, dynamic>();
 
@@ -1962,10 +1983,9 @@ class InAppWebViewController {
 
 ///InAppWebViewControllerAndroid class represents the Android controller that contains only android-specific methods for the WebView.
 class AndroidInAppWebViewController {
-  InAppWebViewController _controller;
+  late InAppWebViewController _controller;
 
   AndroidInAppWebViewController(InAppWebViewController controller) {
-    assert(controller != null);
     this._controller = controller;
   }
 
@@ -2015,7 +2035,7 @@ class AndroidInAppWebViewController {
   ///the current page may not have changed. Also, there may have been redirects resulting in a different URL to that originally requested.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#getOriginalUrl()
-  Future<String> getOriginalUrl() async {
+  Future<String?> getOriginalUrl() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await _controller._channel.invokeMethod('getOriginalUrl', args);
   }
@@ -2026,8 +2046,7 @@ class AndroidInAppWebViewController {
   ///[bottom] `true` to jump to bottom of page.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#pageDown(boolean)
-  Future<bool> pageDown({@required bool bottom}) async {
-    assert(bottom != null);
+  Future<bool> pageDown({required bool bottom}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("bottom", () => bottom);
     return await _controller._channel.invokeMethod('pageDown', args);
@@ -2039,8 +2058,7 @@ class AndroidInAppWebViewController {
   ///[bottom] `true` to jump to the top of the page.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#pageUp(boolean)
-  Future<bool> pageUp({@required bool top}) async {
-    assert(top != null);
+  Future<bool> pageUp({required bool top}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("top", () => top);
     return await _controller._channel.invokeMethod('pageUp', args);
@@ -2055,9 +2073,8 @@ class AndroidInAppWebViewController {
   ///If `true`, [basename] is assumed to be a directory in which a filename will be chosen according to the URL of the current page.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#saveWebArchive(java.lang.String,%20boolean,%20android.webkit.ValueCallback%3Cjava.lang.String%3E)
-  Future<String> saveWebArchive(
-      {@required String basename, @required bool autoname}) async {
-    assert(basename != null && autoname != null);
+  Future<String?> saveWebArchive(
+      {required String basename, required bool autoname}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("basename", () => basename);
     args.putIfAbsent("autoname", () => autoname);
@@ -2110,7 +2127,7 @@ class AndroidInAppWebViewController {
   ///**NOTE**: available only on Android 27+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/androidx/webkit/WebViewCompat#getSafeBrowsingPrivacyPolicyUrl()
-  static Future<String> getSafeBrowsingPrivacyPolicyUrl() async {
+  static Future<String?> getSafeBrowsingPrivacyPolicyUrl() async {
     Map<String, dynamic> args = <String, dynamic>{};
     return await InAppWebViewController._staticChannel
         .invokeMethod('getSafeBrowsingPrivacyPolicyUrl', args);
@@ -2128,14 +2145,13 @@ class AndroidInAppWebViewController {
   ///
   ///All other rules, including wildcards, are invalid. The correct syntax for hosts is defined by [RFC 3986](https://tools.ietf.org/html/rfc3986#section-3.2.2).
   ///
-  ///[hosts] represents the list of hosts. This value must never be null.
+  ///[hosts] represents the list of hosts. This value must never be `null`.
   ///
   ///**NOTE**: available only on Android 27+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/androidx/webkit/WebViewCompat#getSafeBrowsingPrivacyPolicyUrl()
   static Future<bool> setSafeBrowsingWhitelist(
-      {@required List<String> hosts}) async {
-    assert(hosts != null);
+      {required List<String> hosts}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent('hosts', () => hosts);
     return await InAppWebViewController._staticChannel
@@ -2153,22 +2169,37 @@ class AndroidInAppWebViewController {
   ///**NOTE**: available only on Android 26+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/androidx/webkit/WebViewCompat#getCurrentWebViewPackage(android.content.Context)
-  static Future<AndroidWebViewPackageInfo> getCurrentWebViewPackage() async {
+  static Future<AndroidWebViewPackageInfo?> getCurrentWebViewPackage() async {
     Map<String, dynamic> args = <String, dynamic>{};
-    Map<String, dynamic> packageInfo = (await InAppWebViewController
+    Map<String, dynamic>? packageInfo = (await InAppWebViewController
             ._staticChannel
             .invokeMethod('getCurrentWebViewPackage', args))
         ?.cast<String, dynamic>();
     return AndroidWebViewPackageInfo.fromMap(packageInfo);
   }
+
+  ///Enables debugging of web contents (HTML / CSS / JavaScript) loaded into any WebViews of this application.
+  ///This flag can be enabled in order to facilitate debugging of web layouts and JavaScript code running inside WebViews.
+  ///Please refer to WebView documentation for the debugging guide. The default is `false`.
+  ///
+  ///[debuggingEnabled] whether to enable web contents debugging.
+  ///
+  ///**NOTE**: available only on Android 19+.
+  ///
+  ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#setWebContentsDebuggingEnabled(boolean)
+  static Future<void> setWebContentsDebuggingEnabled(bool debuggingEnabled) async {
+    Map<String, dynamic> args = <String, dynamic>{};
+    args.putIfAbsent('debuggingEnabled', () => debuggingEnabled);
+    return await InAppWebViewController._staticChannel
+        .invokeMethod('setWebContentsDebuggingEnabled', args);
+  }
 }
 
 ///InAppWebViewControllerIOS class represents the iOS controller that contains only ios-specific methods for the WebView.
 class IOSInAppWebViewController {
-  InAppWebViewController _controller;
+  late InAppWebViewController _controller;
 
   IOSInAppWebViewController(InAppWebViewController controller) {
-    assert(controller != null);
     this._controller = controller;
   }
 
diff --git a/lib/src/types.dart b/lib/src/types.dart
index e22d7ffb..fc4d3a1f 100755
--- a/lib/src/types.dart
+++ b/lib/src/types.dart
@@ -44,11 +44,15 @@ class ConsoleMessageLevel {
     ConsoleMessageLevel.DEBUG,
   ].toSet();
 
-  static ConsoleMessageLevel fromValue(int value) {
-    if (value != null)
-      return ConsoleMessageLevel.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static ConsoleMessageLevel? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return ConsoleMessageLevel.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -87,16 +91,16 @@ class ConsoleMessageLevel {
 ///It is used by the method [WebView.onLoadResource].
 class LoadedResource {
   ///A string representing the type of resource.
-  String initiatorType;
+  String? initiatorType;
 
   ///Resource URL.
-  String url;
+  String? url;
 
   ///Returns the [DOMHighResTimeStamp](https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp) for the time a resource fetch started.
-  double startTime;
+  double? startTime;
 
   ///Returns the [DOMHighResTimeStamp](https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp) duration to fetch a resource.
-  double duration;
+  double? duration;
 
   LoadedResource({this.initiatorType, this.url, this.startTime, this.duration});
 
@@ -137,7 +141,7 @@ class InAppWebViewInitialData {
   String historyUrl;
 
   InAppWebViewInitialData(
-      {@required this.data,
+      {required this.data,
       this.mimeType = "text/html",
       this.encoding = "utf8",
       this.baseUrl = "about:blank",
@@ -174,12 +178,12 @@ class WebResourceRequest {
   ///The headers associated with the request.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it will be always `null`.
-  Map<String, String> headers;
+  Map<String, String>? headers;
 
   ///The method associated with the request, for example `GET`.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it will be always "GET".
-  String method;
+  String? method;
 
   ///Gets whether a gesture (such as a click) was associated with the request.
   ///For security reasons in certain situations this method may return `false` even though
@@ -187,25 +191,25 @@ class WebResourceRequest {
   ///gesture.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it will be always `false`.
-  bool hasGesture;
+  bool? hasGesture;
 
   ///Whether the request was made in order to fetch the main frame's document.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it will be always `true`.
-  bool isForMainFrame;
+  bool? isForMainFrame;
 
   ///Whether the request was a result of a server-side redirect.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it will be always `false`.
-  bool isRedirect;
+  bool? isRedirect;
 
   WebResourceRequest(
-      {@required this.url,
+      {required this.url,
       this.headers,
-      this.method,
-      this.hasGesture,
-      this.isForMainFrame,
-      this.isRedirect});
+        required this.method,
+        required this.hasGesture,
+        required this.isForMainFrame,
+        required this.isRedirect});
 
   Map<String, dynamic> toMap() {
     return {
@@ -240,24 +244,24 @@ class WebResourceResponse {
   String contentEncoding;
 
   ///The data provided by the resource response.
-  Uint8List data;
+  Uint8List? data;
 
   ///The headers for the resource response. If [headers] isn't `null`, then you need to set also [statusCode] and [reasonPhrase].
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it won't be used.
-  Map<String, String> headers;
+  Map<String, String>? headers;
 
   ///The status code needs to be in the ranges [100, 299], [400, 599]. Causing a redirect by specifying a 3xx code is not supported.
   ///If statusCode is set, then you need to set also [headers] and [reasonPhrase]. This value cannot be `null`.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it won't be used.
-  int statusCode;
+  int? statusCode;
 
   ///The phrase describing the status code, for example `"OK"`. Must be non-empty.
   ///If reasonPhrase is set, then you need to set also [headers] and [reasonPhrase]. This value cannot be `null`.
   ///
   ///**NOTE**: Available on Android 21+. For Android < 21 it won't be used.
-  String reasonPhrase;
+  String? reasonPhrase;
 
   WebResourceResponse(
       {this.contentType = "",
@@ -301,8 +305,8 @@ class CustomSchemeResponse {
   String contentEnconding;
 
   CustomSchemeResponse(
-      {@required this.data,
-      @required this.contentType,
+      {required this.data,
+      required this.contentType,
       this.contentEnconding = 'utf-8'});
 
   Map<String, dynamic> toMap() {
@@ -329,7 +333,7 @@ class CustomSchemeResponse {
 ///To receive notifications of these messages, use the [WebView.onConsoleMessage] event.
 class ConsoleMessage {
   String message;
-  ConsoleMessageLevel messageLevel;
+  ConsoleMessageLevel? messageLevel;
 
   ConsoleMessage(
       {this.message = "", this.messageLevel = ConsoleMessageLevel.LOG});
@@ -351,10 +355,10 @@ class ConsoleMessage {
 ///This class contains a snapshot of the current back/forward list for a [WebView].
 class WebHistory {
   ///List of all [WebHistoryItem]s.
-  List<WebHistoryItem> list;
+  List<WebHistoryItem>? list;
 
   ///Index of the current [WebHistoryItem].
-  int currentIndex;
+  int? currentIndex;
 
   WebHistory({this.list, this.currentIndex});
 
@@ -375,19 +379,19 @@ class WebHistory {
 ///A convenience class for accessing fields in an entry in the back/forward list of a WebView. Each [WebHistoryItem] is a snapshot of the requested history item.
 class WebHistoryItem {
   ///Original url of this history item.
-  String originalUrl;
+  String? originalUrl;
 
   ///Document title of this history item.
-  String title;
+  String? title;
 
   ///Url of this history item.
-  String url;
+  String? url;
 
   ///0-based position index in the back-forward [WebHistory.list].
-  int index;
+  int? index;
 
   ///Position offset respect to the currentIndex of the back-forward [WebHistory.list].
-  int offset;
+  int? offset;
 
   WebHistoryItem(
       {this.originalUrl, this.title, this.url, this.index, this.offset});
@@ -415,13 +419,13 @@ class WebHistoryItem {
 ///Class used by the host application to set the Geolocation permission state for an origin during the [WebView.androidOnGeolocationPermissionsShowPrompt] event.
 class GeolocationPermissionShowPromptResponse {
   ///The origin for which permissions are set.
-  String origin;
+  String? origin;
 
   ///Whether or not the origin should be allowed to use the Geolocation API.
-  bool allow;
+  bool? allow;
 
   ///Whether the permission should be retained beyond the lifetime of a page currently being displayed by a WebView
-  bool retain;
+  bool? retain;
 
   GeolocationPermissionShowPromptResponse(
       {this.origin, this.allow, this.retain});
@@ -443,13 +447,13 @@ class GeolocationPermissionShowPromptResponse {
 ///Class that represents the request of the [WebView.onJsAlert] event.
 class JsAlertRequest {
   ///The url of the page requesting the dialog.
-  String url;
+  String? url;
 
   ///Message to be displayed in the window.
-  String message;
+  String? message;
 
   ///Indicates whether the request was made for the main frame. Available only on iOS.
-  bool iosIsMainFrame;
+  bool? iosIsMainFrame;
 
   JsAlertRequest({this.url, this.message, this.iosIsMainFrame});
 
@@ -495,7 +499,7 @@ class JsAlertResponse {
   bool handledByClient;
 
   ///Action used to confirm that the user hit confirm button.
-  JsAlertResponseAction action;
+  JsAlertResponseAction? action;
 
   JsAlertResponse(
       {this.message = "",
@@ -525,13 +529,13 @@ class JsAlertResponse {
 ///Class that represents the request of the [WebView.onJsConfirm] event.
 class JsConfirmRequest {
   ///The url of the page requesting the dialog.
-  String url;
+  String? url;
 
   ///Message to be displayed in the window.
-  String message;
+  String? message;
 
   ///Indicates whether the request was made for the main frame. Available only on iOS.
-  bool iosIsMainFrame;
+  bool? iosIsMainFrame;
 
   JsConfirmRequest({this.url, this.message, this.iosIsMainFrame});
 
@@ -581,7 +585,7 @@ class JsConfirmResponse {
   bool handledByClient;
 
   ///Action used to confirm that the user hit confirm or cancel button.
-  JsConfirmResponseAction action;
+  JsConfirmResponseAction? action;
 
   JsConfirmResponse(
       {this.message = "",
@@ -613,16 +617,16 @@ class JsConfirmResponse {
 ///Class that represents the request of the [WebView.onJsPrompt] event.
 class JsPromptRequest {
   ///The url of the page requesting the dialog.
-  String url;
+  String? url;
 
   ///Message to be displayed in the window.
-  String message;
+  String? message;
 
   ///The default value displayed in the prompt dialog.
-  String defaultValue;
+  String? defaultValue;
 
   ///Indicates whether the request was made for the main frame. Available only on iOS.
-  bool iosIsMainFrame;
+  bool? iosIsMainFrame;
 
   JsPromptRequest(
       {this.url, this.message, this.defaultValue, this.iosIsMainFrame});
@@ -681,10 +685,10 @@ class JsPromptResponse {
   bool handledByClient;
 
   ///Value of the prompt dialog.
-  String value;
+  String? value;
 
   ///Action used to confirm that the user hit confirm or cancel button.
-  JsPromptResponseAction action;
+  JsPromptResponseAction? action;
 
   JsPromptResponse(
       {this.message = "",
@@ -720,13 +724,13 @@ class JsPromptResponse {
 ///Class that represents the request of the [WebView.androidOnJsBeforeUnload] event.
 class JsBeforeUnloadRequest {
   ///The url of the page requesting the dialog.
-  String url;
+  String? url;
 
   ///Message to be displayed in the window.
-  String message;
+  String? message;
 
   ///Indicates whether the request was made for the main frame. Available only on iOS.
-  bool iosIsMainFrame;
+  bool? iosIsMainFrame;
 
   JsBeforeUnloadRequest({this.url, this.message, this.iosIsMainFrame});
 
@@ -776,7 +780,7 @@ class JsBeforeUnloadResponse {
   bool handledByClient;
 
   ///Action used to confirm that the user hit confirm button.
-  JsBeforeUnloadResponseAction action;
+  JsBeforeUnloadResponseAction? action;
 
   JsBeforeUnloadResponse(
       {this.message = "",
@@ -819,11 +823,16 @@ class SafeBrowsingThreat {
     SafeBrowsingThreat.SAFE_BROWSING_THREAT_BILLING,
   ].toSet();
 
-  static SafeBrowsingThreat fromValue(int value) {
-    if (value != null)
-      return SafeBrowsingThreat.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static SafeBrowsingThreat? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return SafeBrowsingThreat.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
+
     return null;
   }
 
@@ -893,7 +902,7 @@ class SafeBrowsingResponse {
   bool report;
 
   ///Indicate the [SafeBrowsingResponseAction] to take when hitting a malicious URL.
-  SafeBrowsingResponseAction action;
+  SafeBrowsingResponseAction? action;
 
   SafeBrowsingResponse(
       {this.report = true,
@@ -949,7 +958,7 @@ class HttpAuthResponse {
   bool permanentPersistence;
 
   ///Indicate the [HttpAuthResponseAction] to take in response of the authentication challenge.
-  HttpAuthResponseAction action;
+  HttpAuthResponseAction? action;
 
   HttpAuthResponse(
       {this.username = "",
@@ -983,11 +992,10 @@ class HttpAuthChallenge {
   int previousFailureCount;
 
   ///The protection space requiring authentication.
-  ProtectionSpace protectionSpace;
+  ProtectionSpace? protectionSpace;
 
   HttpAuthChallenge(
-      {@required this.previousFailureCount, @required this.protectionSpace})
-      : assert(previousFailureCount != null && protectionSpace != null);
+      {required this.previousFailureCount, required this.protectionSpace});
 
   Map<String, dynamic> toMap() {
     return {
@@ -1017,14 +1025,13 @@ class ProtectionSpace {
   ///A string indicating a protocol-specific subdivision of a single host.
   ///For http and https, this maps to the realm string in http authentication challenges.
   ///For many other protocols it is unused.
-  String realm;
+  String? realm;
 
   ///The port of the server.
-  int port;
+  int? port;
 
   ProtectionSpace(
-      {@required this.host, @required this.protocol, this.realm, this.port})
-      : assert(host != null && protocol != null);
+      {required this.host, required this.protocol, this.realm, this.port});
 
   Map<String, dynamic> toMap() {
     return {"host": host, "protocol": protocol, "realm": realm, "port": port};
@@ -1049,8 +1056,7 @@ class HttpAuthCredential {
   ///Represents the password.
   String password;
 
-  HttpAuthCredential({@required this.username, @required this.password})
-      : assert(username != null && password != null);
+  HttpAuthCredential({required this.username, required this.password});
 
   Map<String, dynamic> toMap() {
     return {"username": username, "password": password};
@@ -1070,18 +1076,18 @@ class HttpAuthCredential {
 ///It used by [HttpAuthCredentialDatabase.getAllAuthCredentials].
 class ProtectionSpaceHttpAuthCredentials {
   ///The protection space.
-  ProtectionSpace protectionSpace;
+  ProtectionSpace? protectionSpace;
 
   ///The list of all its http authentication credentials.
-  List<HttpAuthCredential> credentials;
+  List<HttpAuthCredential>? credentials;
 
   ProtectionSpaceHttpAuthCredentials({this.protectionSpace, this.credentials});
 
   Map<String, dynamic> toMap() {
     return {
       "protectionSpace": protectionSpace?.toMap(),
-      "credentials":
-          credentials?.map((credential) => credential?.toMap())?.toList()
+      "credentials": credentials != null ?
+          credentials!.map((credential) => credential.toMap()).toList() : null
     };
   }
 
@@ -1118,7 +1124,7 @@ class ServerTrustAuthResponseAction {
 ///ServerTrustAuthResponse class represents the response used by the [WebView.onReceivedServerTrustAuthRequest] event.
 class ServerTrustAuthResponse {
   ///Indicate the [ServerTrustAuthResponseAction] to take in response of the server trust authentication challenge.
-  ServerTrustAuthResponseAction action;
+  ServerTrustAuthResponseAction? action;
 
   ServerTrustAuthResponse({this.action = ServerTrustAuthResponseAction.CANCEL});
 
@@ -1140,22 +1146,22 @@ class ServerTrustAuthResponse {
 ///It provides all the information about the challenge.
 class ServerTrustChallenge {
   ///The protection space requiring authentication.
-  ProtectionSpace protectionSpace;
+  ProtectionSpace? protectionSpace;
 
   ///Android-specific primary error associated to the server SSL certificate.
-  AndroidSslError androidError;
+  AndroidSslError? androidError;
 
   ///iOS-specific primary error associated to the server SSL certificate.
-  IOSSslError iosError;
+  IOSSslError? iosError;
 
   ///The message associated to the [androidError]/[iosError].
-  String message;
+  String? message;
 
   ///The SSL certificate used for this challenge.
-  SslCertificate sslCertificate;
+  SslCertificate? sslCertificate;
 
   ServerTrustChallenge(
-      {@required this.protectionSpace,
+      {required this.protectionSpace,
       this.androidError,
       this.iosError,
       this.message,
@@ -1211,21 +1217,21 @@ class ClientCertResponse {
   String certificatePath;
 
   ///The certificate password.
-  String certificatePassword;
+  String? certificatePassword;
 
   ///An Android-specific property used by Java [KeyStore](https://developer.android.com/reference/java/security/KeyStore) class to get the instance.
-  String androidKeyStoreType;
+  String? androidKeyStoreType;
 
   ///Indicate the [ClientCertResponseAction] to take in response of the client certificate challenge.
-  ClientCertResponseAction action;
+  ClientCertResponseAction? action;
 
   ClientCertResponse(
-      {this.certificatePath,
+      {required this.certificatePath,
       this.certificatePassword = "",
       this.androidKeyStoreType = "PKCS12",
       this.action = ClientCertResponseAction.CANCEL}) {
     if (this.action == ClientCertResponseAction.PROCEED)
-      assert(certificatePath != null && certificatePath.isNotEmpty);
+      assert(certificatePath.isNotEmpty);
   }
 
   Map<String, dynamic> toMap() {
@@ -1253,11 +1259,10 @@ class ClientCertChallenge {
   ///The protection space requiring authentication.
   ProtectionSpace protectionSpace;
 
-  ClientCertChallenge({@required this.protectionSpace})
-      : assert(protectionSpace != null);
+  ClientCertChallenge({required this.protectionSpace});
 
   Map<String, dynamic> toMap() {
-    return {"protectionSpace": protectionSpace?.toMap()};
+    return {"protectionSpace": protectionSpace.toMap()};
   }
 
   Map<String, dynamic> toJson() {
@@ -1276,16 +1281,15 @@ class Favicon {
   String url;
 
   ///The relationship between the current web page and the favicon image.
-  String rel;
+  String? rel;
 
   ///The width of the favicon image.
-  int width;
+  int? width;
 
   ///The height of the favicon image.
-  int height;
+  int? height;
 
-  Favicon({@required this.url, this.rel, this.width, this.height})
-      : assert(url != null);
+  Favicon({required this.url, this.rel, this.width, this.height});
 
   Map<String, dynamic> toMap() {
     return {"url": url, "rel": rel, "width": width, "height": height};
@@ -1314,11 +1318,15 @@ class AndroidCacheMode {
     AndroidCacheMode.LOAD_CACHE_ONLY,
   ].toSet();
 
-  static AndroidCacheMode fromValue(int value) {
-    if (value != null)
-      return AndroidCacheMode.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidCacheMode? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidCacheMode.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1373,11 +1381,15 @@ class AndroidActionModeMenuItem {
     AndroidActionModeMenuItem.MENU_ITEM_PROCESS_TEXT,
   ].toSet();
 
-  static AndroidActionModeMenuItem fromValue(int value) {
-    if (value != null)
-      return AndroidActionModeMenuItem.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidActionModeMenuItem? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidActionModeMenuItem.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1432,11 +1444,15 @@ class AndroidForceDark {
     AndroidForceDark.FORCE_DARK_ON,
   ].toSet();
 
-  static AndroidForceDark fromValue(int value) {
-    if (value != null)
-      return AndroidForceDark.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidForceDark? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidForceDark.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1483,11 +1499,15 @@ class AndroidLayoutAlgorithm {
     AndroidLayoutAlgorithm.NARROW_COLUMNS,
   ].toSet();
 
-  static AndroidLayoutAlgorithm fromValue(String value) {
-    if (value != null)
-      return AndroidLayoutAlgorithm.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidLayoutAlgorithm? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return AndroidLayoutAlgorithm.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1530,11 +1550,15 @@ class AndroidMixedContentMode {
     AndroidMixedContentMode.MIXED_CONTENT_COMPATIBILITY_MODE,
   ].toSet();
 
-  static AndroidMixedContentMode fromValue(int value) {
-    if (value != null)
-      return AndroidMixedContentMode.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidMixedContentMode? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidMixedContentMode.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1588,11 +1612,15 @@ class IOSWKSelectionGranularity {
     IOSWKSelectionGranularity.CHARACTER,
   ].toSet();
 
-  static IOSWKSelectionGranularity fromValue(int value) {
-    if (value != null)
-      return IOSWKSelectionGranularity.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSWKSelectionGranularity? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSWKSelectionGranularity.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1642,11 +1670,15 @@ class IOSWKDataDetectorTypes {
     IOSWKDataDetectorTypes.ALL,
   ].toSet();
 
-  static IOSWKDataDetectorTypes fromValue(String value) {
-    if (value != null)
-      return IOSWKDataDetectorTypes.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSWKDataDetectorTypes? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return IOSWKDataDetectorTypes.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1708,11 +1740,15 @@ class IOSUIScrollViewDecelerationRate {
     IOSUIScrollViewDecelerationRate.FAST,
   ].toSet();
 
-  static IOSUIScrollViewDecelerationRate fromValue(String value) {
-    if (value != null)
-      return IOSUIScrollViewDecelerationRate.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSUIScrollViewDecelerationRate? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return IOSUIScrollViewDecelerationRate.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1746,11 +1782,15 @@ class UserPreferredContentMode {
     UserPreferredContentMode.DESKTOP,
   ].toSet();
 
-  static UserPreferredContentMode fromValue(int value) {
-    if (value != null)
-      return UserPreferredContentMode.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static UserPreferredContentMode? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return UserPreferredContentMode.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1803,11 +1843,15 @@ class IOSUIModalPresentationStyle {
     IOSUIModalPresentationStyle.AUTOMATIC,
   ].toSet();
 
-  static IOSUIModalPresentationStyle fromValue(int value) {
-    if (value != null)
-      return IOSUIModalPresentationStyle.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSUIModalPresentationStyle? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSUIModalPresentationStyle.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1893,11 +1937,15 @@ class IOSUIModalTransitionStyle {
     IOSUIModalTransitionStyle.PARTIAL_CURL,
   ].toSet();
 
-  static IOSUIModalTransitionStyle fromValue(int value) {
-    if (value != null)
-      return IOSUIModalTransitionStyle.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSUIModalTransitionStyle? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSUIModalTransitionStyle.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1956,11 +2004,15 @@ class IOSSafariDismissButtonStyle {
     IOSSafariDismissButtonStyle.CANCEL,
   ].toSet();
 
-  static IOSSafariDismissButtonStyle fromValue(int value) {
-    if (value != null)
-      return IOSSafariDismissButtonStyle.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSSafariDismissButtonStyle? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSSafariDismissButtonStyle.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -1997,13 +2049,13 @@ class IOSSafariDismissButtonStyle {
 ///Class that represents the options that can be used for a [WebView].
 class InAppWebViewGroupOptions {
   ///Cross-platform options.
-  InAppWebViewOptions crossPlatform;
+  InAppWebViewOptions? crossPlatform;
 
   ///Android-specific options.
-  AndroidInAppWebViewOptions android;
+  AndroidInAppWebViewOptions? android;
 
   ///iOS-specific options.
-  IOSInAppWebViewOptions ios;
+  IOSInAppWebViewOptions? ios;
 
   InAppWebViewGroupOptions({this.crossPlatform, this.android, this.ios}) {
     this.crossPlatform = this.crossPlatform ?? InAppWebViewOptions();
@@ -2053,16 +2105,16 @@ class InAppWebViewGroupOptions {
 ///Class that represents the options that can be used for an [InAppBrowser] WebView.
 class InAppBrowserClassOptions {
   ///Cross-platform options.
-  InAppBrowserOptions crossPlatform;
+  InAppBrowserOptions? crossPlatform;
 
   ///Android-specific options.
-  AndroidInAppBrowserOptions android;
+  AndroidInAppBrowserOptions? android;
 
   ///iOS-specific options.
-  IOSInAppBrowserOptions ios;
+  IOSInAppBrowserOptions? ios;
 
   ///WebView options.
-  InAppWebViewGroupOptions inAppWebViewGroupOptions;
+  InAppWebViewGroupOptions? inAppWebViewGroupOptions;
 
   InAppBrowserClassOptions(
       {this.crossPlatform,
@@ -2109,16 +2161,16 @@ class InAppBrowserClassOptions {
         InAppBrowserOptions.fromMap(options);
     inAppBrowserClassOptions.inAppWebViewGroupOptions =
         InAppWebViewGroupOptions();
-    inAppBrowserClassOptions.inAppWebViewGroupOptions.crossPlatform =
+    inAppBrowserClassOptions.inAppWebViewGroupOptions!.crossPlatform =
         InAppWebViewOptions.fromMap(options);
     if (defaultTargetPlatform == TargetPlatform.android) {
       inAppBrowserClassOptions.android =
           AndroidInAppBrowserOptions.fromMap(options);
-      inAppBrowserClassOptions.inAppWebViewGroupOptions.android =
+      inAppBrowserClassOptions.inAppWebViewGroupOptions!.android =
           AndroidInAppWebViewOptions.fromMap(options);
     } else if (defaultTargetPlatform == TargetPlatform.iOS) {
       inAppBrowserClassOptions.ios = IOSInAppBrowserOptions.fromMap(options);
-      inAppBrowserClassOptions.inAppWebViewGroupOptions.ios =
+      inAppBrowserClassOptions.inAppWebViewGroupOptions!.ios =
           IOSInAppWebViewOptions.fromMap(options);
     }
 
@@ -2133,10 +2185,10 @@ class InAppBrowserClassOptions {
 ///Class that represents the options that can be used for an [ChromeSafariBrowser] window.
 class ChromeSafariBrowserClassOptions {
   ///Android-specific options.
-  AndroidChromeCustomTabsOptions android;
+  AndroidChromeCustomTabsOptions? android;
 
   ///iOS-specific options.
-  IOSSafariOptions ios;
+  IOSSafariOptions? ios;
 
   ChromeSafariBrowserClassOptions({this.android, this.ios}) {
     this.android = this.android ?? AndroidChromeCustomTabsOptions();
@@ -2213,11 +2265,15 @@ class AjaxRequestEventType {
     AjaxRequestEventType.TIMEOUT,
   ].toSet();
 
-  static AjaxRequestEventType fromValue(String value) {
-    if (value != null)
-      return AjaxRequestEventType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AjaxRequestEventType? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return AjaxRequestEventType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -2256,20 +2312,20 @@ class AjaxRequestEventType {
 ///Class used by [AjaxRequest] class. It represents events measuring progress of an [AjaxRequest].
 class AjaxRequestEvent {
   ///Event type.
-  AjaxRequestEventType type;
+  AjaxRequestEventType? type;
 
   ///Is a Boolean flag indicating if the total work to be done, and the amount of work already done, by the underlying process is calculable.
   ///In other words, it tells if the progress is measurable or not.
-  bool lengthComputable;
+  bool? lengthComputable;
 
   ///Is an integer representing the amount of work already performed by the underlying process.
   ///The ratio of work done can be calculated with the property and [AjaxRequestEvent.total].
   ///When downloading a resource using HTTP, this only represent the part of the content itself, not headers and other overhead.
-  int loaded;
+  int? loaded;
 
   ///Is an integer representing the total amount of work that the underlying process is in the progress of performing.
   ///When downloading a resource using HTTP, this only represent the content itself, not headers and other overhead.
-  int total;
+  int? total;
 
   AjaxRequestEvent({this.type, this.lengthComputable, this.loaded, this.total});
 }
@@ -2288,11 +2344,15 @@ class AjaxRequestReadyState {
     AjaxRequestReadyState.DONE,
   ].toSet();
 
-  static AjaxRequestReadyState fromValue(int value) {
-    if (value != null)
-      return AjaxRequestReadyState.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AjaxRequestReadyState? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AjaxRequestReadyState.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -2367,68 +2427,68 @@ class AjaxRequest {
   dynamic data;
 
   ///The HTTP request method of the `XMLHttpRequest` request.
-  String method;
+  String? method;
 
   ///The URL of the `XMLHttpRequest` request.
-  String url;
+  String? url;
 
   ///An optional Boolean parameter, defaulting to true, indicating whether or not the request is performed asynchronously.
-  bool isAsync;
+  bool? isAsync;
 
   ///The optional user name to use for authentication purposes; by default, this is the null value.
-  String user;
+  String? user;
 
   ///The optional password to use for authentication purposes; by default, this is the null value.
-  String password;
+  String? password;
 
   ///The XMLHttpRequest.withCredentials property is a Boolean that indicates whether or not cross-site Access-Control requests
   ///should be made using credentials such as cookies, authorization headers or TLS client certificates.
   ///Setting withCredentials has no effect on same-site requests.
   ///In addition, this flag is also used to indicate when cookies are to be ignored in the response. The default is false.
-  bool withCredentials;
+  bool? withCredentials;
 
   ///The HTTP request headers.
-  AjaxRequestHeaders headers;
+  AjaxRequestHeaders? headers;
 
   ///The state of the `XMLHttpRequest` request.
-  AjaxRequestReadyState readyState;
+  AjaxRequestReadyState? readyState;
 
   ///The numerical HTTP [status code](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status) of the `XMLHttpRequest`'s response.
-  int status;
+  int? status;
 
   ///The serialized URL of the response or the empty string if the URL is null.
   ///If the URL is returned, any URL fragment present in the URL will be stripped away.
   ///The value of responseURL will be the final URL obtained after any redirects.
-  String responseURL;
+  String? responseURL;
 
   ///It is an enumerated string value specifying the type of data contained in the response.
   ///It also lets the author change the [response type](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/responseType).
   ///If an empty string is set as the value of responseType, the default value of text is used.
-  String responseType;
+  String? responseType;
 
   ///The response's body content. The content-type depends on the [AjaxRequest.reponseType].
   dynamic response;
 
   ///The text received from a server following a request being sent.
-  String responseText;
+  String? responseText;
 
   ///The HTML or XML string retrieved by the request or null if the request was unsuccessful, has not yet been sent, or if the data can't be parsed as XML or HTML.
-  String responseXML;
+  String? responseXML;
 
   ///A String containing the response's status message as returned by the HTTP server.
   ///Unlike [AjaxRequest.status] which indicates a numerical status code, this property contains the text of the response status, such as "OK" or "Not Found".
   ///If the request's readyState is in [AjaxRequestReadyState.UNSENT] or [AjaxRequestReadyState.OPENED] state, the value of statusText will be an empty string.
   ///If the server response doesn't explicitly specify a status text, statusText will assume the default value "OK".
-  String statusText;
+  String? statusText;
 
   ///All the response headers or returns null if no response has been received. If a network error happened, an empty string is returned.
-  Map<dynamic, dynamic> responseHeaders;
+  Map<dynamic, dynamic>? responseHeaders;
 
   ///Event type of the `XMLHttpRequest` request.
-  AjaxRequestEvent event;
+  AjaxRequestEvent? event;
 
   ///Indicates the [AjaxRequestAction] that can be used to control the `XMLHttpRequest` request.
-  AjaxRequestAction action;
+  AjaxRequestAction? action;
 
   AjaxRequest(
       {this.data,
@@ -2507,7 +2567,7 @@ class FetchRequestAction {
 ///Class that is an interface for [FetchRequestCredentialDefault], [FetchRequestFederatedCredential] and [FetchRequestPasswordCredential] classes.
 class FetchRequestCredential {
   ///Type of credentials.
-  String type;
+  String? type;
 
   FetchRequestCredential({this.type});
 
@@ -2528,7 +2588,7 @@ class FetchRequestCredential {
 ///Class that represents the default credentials used by an [FetchRequest].
 class FetchRequestCredentialDefault extends FetchRequestCredential {
   ///The value of the credentials.
-  String value;
+  String? value;
 
   FetchRequestCredentialDefault({type, this.value}) : super(type: type);
 
@@ -2555,16 +2615,16 @@ class FetchRequestFederatedCredential extends FetchRequestCredential {
   dynamic id;
 
   ///The name associated with a credential. It should be a human-readable, public name.
-  String name;
+  String? name;
 
   ///Credential's federated identity protocol.
-  String protocol;
+  String? protocol;
 
   ///Credential's federated identity provider.
-  String provider;
+  String? provider;
 
   ///URL pointing to an image for an icon. This image is intended for display in a credential chooser. The URL must be accessible without authentication.
-  String iconURL;
+  String? iconURL;
 
   FetchRequestFederatedCredential(
       {type, this.id, this.name, this.protocol, this.provider, this.iconURL})
@@ -2597,13 +2657,13 @@ class FetchRequestPasswordCredential extends FetchRequestCredential {
   dynamic id;
 
   ///The name associated with a credential. It should be a human-readable, public name.
-  String name;
+  String? name;
 
   ///The password of the credential.
-  String password;
+  String? password;
 
   ///URL pointing to an image for an icon. This image is intended for display in a credential chooser. The URL must be accessible without authentication.
-  String iconURL;
+  String? iconURL;
 
   FetchRequestPasswordCredential(
       {type, this.id, this.name, this.password, this.iconURL})
@@ -2632,43 +2692,43 @@ class FetchRequestPasswordCredential extends FetchRequestCredential {
 ///Class that represents a HTTP request created with JavaScript using the [Fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch).
 class FetchRequest {
   ///The URL of the request.
-  String url;
+  String? url;
 
   ///The HTTP request method used of the request.
-  String method;
+  String? method;
 
   ///The HTTP request headers.
-  Map<String, dynamic> headers;
+  Map<String, dynamic>? headers;
 
   ///Body of the request.
-  Uint8List body;
+  Uint8List? body;
 
   ///The mode used by the request.
-  String mode;
+  String? mode;
 
   ///The request credentials used by the request.
-  FetchRequestCredential credentials;
+  FetchRequestCredential? credentials;
 
   ///The cache mode used by the request.
-  String cache;
+  String? cache;
 
   ///The redirect mode used by the request.
-  String redirect;
+  String? redirect;
 
   ///A String specifying no-referrer, client, or a URL.
-  String referrer;
+  String? referrer;
 
   ///The value of the referer HTTP header.
-  String referrerPolicy;
+  String? referrerPolicy;
 
   ///Contains the subresource integrity value of the request.
-  String integrity;
+  String? integrity;
 
   ///The keepalive option used to allow the request to outlive the page.
-  bool keepalive;
+  bool? keepalive;
 
   ///Indicates the [FetchRequestAction] that can be used to control the request.
-  FetchRequestAction action;
+  FetchRequestAction? action;
 
   FetchRequest(
       {this.url,
@@ -2712,7 +2772,7 @@ class FetchRequest {
     return toMap().toString();
   }
 
-  static FetchRequestCredential fromMap(credentialsMap) {
+  static FetchRequestCredential? fromMap(credentialsMap) {
     if (credentialsMap != null) {
       if (credentialsMap["type"] == "default") {
         return FetchRequestCredentialDefault(
@@ -2755,11 +2815,15 @@ class ContentBlockerTriggerResourceType {
     ContentBlockerTriggerResourceType.RAW,
   ].toSet();
 
-  static ContentBlockerTriggerResourceType fromValue(String value) {
-    if (value != null)
-      return ContentBlockerTriggerResourceType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static ContentBlockerTriggerResourceType? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return ContentBlockerTriggerResourceType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -2802,11 +2866,15 @@ class ContentBlockerTriggerLoadType {
     ContentBlockerTriggerLoadType.THIRD_PARTY,
   ].toSet();
 
-  static ContentBlockerTriggerLoadType fromValue(String value) {
-    if (value != null)
-      return ContentBlockerTriggerLoadType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static ContentBlockerTriggerLoadType? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return ContentBlockerTriggerLoadType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -2841,11 +2909,15 @@ class ContentBlockerActionType {
     ContentBlockerActionType.MAKE_HTTPS,
   ].toSet();
 
-  static ContentBlockerActionType fromValue(String value) {
-    if (value != null)
-      return ContentBlockerActionType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static ContentBlockerActionType? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return ContentBlockerActionType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -2884,41 +2956,41 @@ class Cookie {
   ///The cookie expiration date in milliseconds.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  int expiresDate;
+  int? expiresDate;
 
   ///Indicates if the cookie is a session only cookie.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  bool isSessionOnly;
+  bool? isSessionOnly;
 
   ///The cookie domain.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  String domain;
+  String? domain;
 
   ///The cookie same site policy.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  HTTPCookieSameSitePolicy sameSite;
+  HTTPCookieSameSitePolicy? sameSite;
 
   ///Indicates if the cookie is secure or not.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  bool isSecure;
+  bool? isSecure;
 
   ///Indicates if the cookie is a http only cookie.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  bool isHttpOnly;
+  bool? isHttpOnly;
 
   ///The cookie path.
   ///
   ///**NOTE**: on Android it will be always `null`.
-  String path;
+  String? path;
 
   Cookie(
-      {@required this.name,
-      @required this.value,
+      {required this.name,
+      required this.value,
       this.expiresDate,
       this.isSessionOnly,
       this.domain,
@@ -2977,7 +3049,7 @@ class PermissionRequestResponse {
   List<String> resources;
 
   ///Indicate the [PermissionRequestResponseAction] to take in response of a permission request.
-  PermissionRequestResponseAction action;
+  PermissionRequestResponseAction? action;
 
   PermissionRequestResponse(
       {this.resources = const [],
@@ -3039,11 +3111,15 @@ class IOSWKNavigationType {
     IOSWKNavigationType.OTHER,
   ].toSet();
 
-  static IOSWKNavigationType fromValue(int value) {
-    if (value != null)
-      return IOSWKNavigationType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSWKNavigationType? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSWKNavigationType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3079,10 +3155,10 @@ class ShouldOverrideUrlLoadingRequest {
   String url;
 
   ///Represents the method of the navigation request. On Android < 21, this value is always `GET`.
-  String method;
+  String? method;
 
   ///Represents the headers of the navigation request. On Android < 21, this is always `null`.
-  Map<String, String> headers;
+  Map<String, String>? headers;
 
   ///Indicates whether the request was made for the main frame. On Android < 21, this is always `true`.
   bool isForMainFrame;
@@ -3093,19 +3169,19 @@ class ShouldOverrideUrlLoadingRequest {
   ///gesture.
   ///
   ///Available only on Android. On Android < 24, this is always `false`.
-  bool androidHasGesture;
+  bool? androidHasGesture;
 
   ///Gets whether the request was a result of a server-side redirect. Available only on Android. On Android < 21, this is always `false`.
-  bool androidIsRedirect;
+  bool? androidIsRedirect;
 
   ///The type of action triggering the navigation. Available only on iOS.
-  IOSWKNavigationType iosWKNavigationType;
+  IOSWKNavigationType? iosWKNavigationType;
 
   ShouldOverrideUrlLoadingRequest(
-      {this.url,
+      {required this.url,
       this.method,
       this.headers,
-      this.isForMainFrame,
+      required this.isForMainFrame,
       this.androidHasGesture,
       this.androidIsRedirect,
       this.iosWKNavigationType});
@@ -3137,26 +3213,26 @@ class CreateWindowRequest {
   ///The URL of the request.
   ///
   ///**NOTE**: On Android, if the window has been created using JavaScript, this will be `null`.
-  String url;
+  String? url;
 
   ///The window id. Used by [WebView] to create a new WebView.
   int windowId;
 
   ///Indicates if the new window should be a dialog, rather than a full-size window. Available only on Android.
-  bool androidIsDialog;
+  bool? androidIsDialog;
 
   ///Indicates if the request was initiated by a user gesture, such as the user clicking a link. Available only on Android.
-  bool androidIsUserGesture;
+  bool? androidIsUserGesture;
 
   ///The type of action triggering the navigation. Available only on iOS.
-  IOSWKNavigationType iosWKNavigationType;
+  IOSWKNavigationType? iosWKNavigationType;
 
   ///Whether the request was made in order to fetch the main frame's document. Available only on iOS.
-  bool iosIsForMainFrame;
+  bool? iosIsForMainFrame;
 
   CreateWindowRequest(
       {this.url,
-      this.windowId,
+      required this.windowId,
       this.androidIsDialog,
       this.androidIsUserGesture,
       this.iosWKNavigationType,
@@ -3167,7 +3243,7 @@ class CreateWindowRequest {
       "androidIsDialog": androidIsDialog,
       "androidIsUserGesture": androidIsUserGesture,
       "iosWKNavigationType": iosWKNavigationType?.toValue(),
-      "iosUrl": url,
+      "url": url,
       "windowId": windowId
     };
   }
@@ -3186,13 +3262,13 @@ class CreateWindowRequest {
 ///An origin comprises the host, scheme and port of a URI. See [AndroidWebStorageManager] for details.
 class AndroidWebStorageOrigin {
   ///The string representation of this origin.
-  String origin;
+  String? origin;
 
   ///The quota for this origin, for the Web SQL Database API, in bytes.
-  int quota;
+  int? quota;
 
   ///The total amount of storage currently being used by this origin, for all JavaScript storage APIs, in bytes.
-  int usage;
+  int? usage;
 
   AndroidWebStorageOrigin({this.origin, this.quota, this.usage});
 
@@ -3231,11 +3307,15 @@ class IOSWKWebsiteDataType {
     IOSWKWebsiteDataType.WKWebsiteDataTypeServiceWorkerRegistrations,
   ].toSet();
 
-  static IOSWKWebsiteDataType fromValue(String value) {
-    if (value != null)
-      return IOSWKWebsiteDataType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSWKWebsiteDataType? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return IOSWKWebsiteDataType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3317,17 +3397,19 @@ class IOSWKWebsiteDataType {
 ///**NOTE**: available on iOS 9.0+.
 class IOSWKWebsiteDataRecord {
   ///The display name for the data record. This is usually the domain name.
-  String displayName;
+  String? displayName;
 
   ///The various types of website data that exist for this data record.
-  Set<IOSWKWebsiteDataType> dataTypes;
+  Set<IOSWKWebsiteDataType>? dataTypes;
 
   IOSWKWebsiteDataRecord({this.displayName, this.dataTypes});
 
   Map<String, dynamic> toMap() {
     List<String> dataTypesString = [];
-    for (var dataType in dataTypes) {
-      dataTypesString.add(dataType.toValue());
+    if (dataTypes != null) {
+      for (var dataType in dataTypes!) {
+        dataTypesString.add(dataType.toValue());
+      }
     }
 
     return {"displayName": displayName, "dataTypes": dataTypesString};
@@ -3360,11 +3442,15 @@ class InAppWebViewHitTestResultType {
     InAppWebViewHitTestResultType.EDIT_TEXT_TYPE,
   ].toSet();
 
-  static InAppWebViewHitTestResultType fromValue(int value) {
-    if (value != null)
-      return InAppWebViewHitTestResultType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static InAppWebViewHitTestResultType? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return InAppWebViewHitTestResultType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3429,10 +3515,10 @@ class InAppWebViewHitTestResultType {
 ///Class that represents the hit result for hitting an HTML elements.
 class InAppWebViewHitTestResult {
   ///The type of the hit test result.
-  InAppWebViewHitTestResultType type;
+  InAppWebViewHitTestResultType? type;
 
   ///Additional type-dependant information about the result.
-  String extra;
+  String? extra;
 
   InAppWebViewHitTestResult({this.type, this.extra});
 
@@ -3482,9 +3568,9 @@ class RenderProcessGoneDetail {
 
   /// Returns the renderer priority that was set at the time that the renderer exited. This may be greater than the priority that
   /// any individual [WebView] requested using [].
-  RendererPriority rendererPriorityAtExit;
+  RendererPriority? rendererPriorityAtExit;
 
-  RenderProcessGoneDetail({this.didCrash, this.rendererPriorityAtExit});
+  RenderProcessGoneDetail({required this.didCrash, this.rendererPriorityAtExit});
 
   Map<String, dynamic> toMap() {
     return {
@@ -3515,11 +3601,15 @@ class RendererPriority {
     RendererPriority.RENDERER_PRIORITY_IMPORTANT,
   ].toSet();
 
-  static RendererPriority fromValue(int value) {
-    if (value != null)
-      return RendererPriority.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static RendererPriority? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return RendererPriority.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3563,14 +3653,14 @@ class RendererPriority {
 ///Any other setting will result in WebView renderers being killed by the system more aggressively than the application.
 class RendererPriorityPolicy {
   ///The minimum priority at which this WebView desires the renderer process to be bound.
-  RendererPriority rendererRequestedPriority;
+  RendererPriority? rendererRequestedPriority;
 
   ///If true, this flag specifies that when this WebView is not visible, it will be treated as if it had requested a priority of [RendererPriority.RENDERER_PRIORITY_WAIVED].
   bool waivedWhenNotVisible;
 
   RendererPriorityPolicy(
-      {@required this.rendererRequestedPriority,
-      @required this.waivedWhenNotVisible});
+      {required this.rendererRequestedPriority,
+      required this.waivedWhenNotVisible});
 
   Map<String, dynamic> toMap() {
     return {
@@ -3588,7 +3678,7 @@ class RendererPriorityPolicy {
     return toMap().toString();
   }
 
-  static RendererPriorityPolicy fromMap(Map<String, dynamic> map) {
+  static RendererPriorityPolicy? fromMap(Map<String, dynamic>? map) {
     return map != null
         ? RendererPriorityPolicy(
             rendererRequestedPriority:
@@ -3644,11 +3734,15 @@ class AndroidOverScrollMode {
     AndroidOverScrollMode.OVER_SCROLL_NEVER,
   ].toSet();
 
-  static AndroidOverScrollMode fromValue(int value) {
-    if (value != null)
-      return AndroidOverScrollMode.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidOverScrollMode? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidOverScrollMode.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3702,11 +3796,15 @@ class AndroidScrollBarStyle {
     AndroidScrollBarStyle.SCROLLBARS_OUTSIDE_INSET,
   ].toSet();
 
-  static AndroidScrollBarStyle fromValue(int value) {
-    if (value != null)
-      return AndroidScrollBarStyle.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidScrollBarStyle? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidScrollBarStyle.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3765,11 +3863,15 @@ class AndroidVerticalScrollbarPosition {
     AndroidVerticalScrollbarPosition.SCROLLBAR_POSITION_RIGHT,
   ].toSet();
 
-  static AndroidVerticalScrollbarPosition fromValue(int value) {
-    if (value != null)
-      return AndroidVerticalScrollbarPosition.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidVerticalScrollbarPosition? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidVerticalScrollbarPosition.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3809,14 +3911,14 @@ class AndroidVerticalScrollbarPosition {
 ///Class that represents an Android WebView package info.
 class AndroidWebViewPackageInfo {
   ///The version name of this WebView package.
-  String versionName;
+  String? versionName;
 
   ///The name of this WebView package.
-  String packageName;
+  String? packageName;
 
   AndroidWebViewPackageInfo({this.versionName, this.packageName});
 
-  static AndroidWebViewPackageInfo fromMap(Map<String, dynamic> map) {
+  static AndroidWebViewPackageInfo? fromMap(Map<String, dynamic>? map) {
     return map != null
         ? AndroidWebViewPackageInfo(
             versionName: map["versionName"], packageName: map["packageName"])
@@ -3840,13 +3942,13 @@ class AndroidWebViewPackageInfo {
 ///Class that represents the result used by the [InAppWebViewController.requestFocusNodeHref] method.
 class RequestFocusNodeHrefResult {
   ///The anchor's href attribute.
-  String url;
+  String? url;
 
   ///The anchor's text.
-  String title;
+  String? title;
 
   ///The image's src attribute.
-  String src;
+  String? src;
 
   RequestFocusNodeHrefResult({this.url, this.title, this.src});
 
@@ -3867,7 +3969,7 @@ class RequestFocusNodeHrefResult {
 ///Class that represents the result used by the [InAppWebViewController.requestImageRef] method.
 class RequestImageRefResult {
   ///The image's url.
-  String url;
+  String? url;
 
   RequestImageRefResult({this.url});
 
@@ -3890,13 +3992,13 @@ class RequestImageRefResult {
 ///Class that represents a `<meta>` HTML tag. It is used by the [InAppWebViewController.getMetaTags] method.
 class MetaTag {
   ///The meta tag name value.
-  String name;
+  String? name;
 
   ///The meta tag content value.
-  String content;
+  String? content;
 
   ///The meta tag attributes list.
-  List<MetaTagAttribute> attrs;
+  List<MetaTagAttribute>? attrs;
 
   MetaTag({this.name, this.content, this.attrs});
 
@@ -3917,10 +4019,10 @@ class MetaTag {
 ///Class that represents an attribute of a `<meta>` HTML tag. It is used by the [MetaTag] class.
 class MetaTagAttribute {
   ///The attribute name.
-  String name;
+  String? name;
 
   ///The attribute value.
-  String value;
+  String? value;
 
   MetaTagAttribute({this.name, this.value});
 
@@ -3953,11 +4055,15 @@ class WebStorageType {
     WebStorageType.SESSION_STORAGE,
   ].toSet();
 
-  static WebStorageType fromValue(String value) {
-    if (value != null)
-      return WebStorageType.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static WebStorageType? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return WebStorageType.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -3992,11 +4098,15 @@ class HTTPCookieSameSitePolicy {
     HTTPCookieSameSitePolicy.NONE,
   ].toSet();
 
-  static HTTPCookieSameSitePolicy fromValue(String value) {
-    if (value != null)
-      return HTTPCookieSameSitePolicy.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static HTTPCookieSameSitePolicy? fromValue(String? value) {
+    if (value != null) {
+      try {
+        return HTTPCookieSameSitePolicy.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -4044,11 +4154,15 @@ class AndroidSslError {
     AndroidSslError.SSL_INVALID,
   ].toSet();
 
-  static AndroidSslError fromValue(int value) {
-    if (value != null)
-      return AndroidSslError.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static AndroidSslError? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return AndroidSslError.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -4113,11 +4227,15 @@ class IOSSslError {
     IOSSslError.OTHER_ERROR,
   ].toSet();
 
-  static IOSSslError fromValue(int value) {
-    if (value != null)
-      return IOSSslError.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSSslError? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSSslError.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -4181,11 +4299,15 @@ class IOSUIScrollViewContentInsetAdjustmentBehavior {
     IOSUIScrollViewContentInsetAdjustmentBehavior.ALWAYS,
   ].toSet();
 
-  static IOSUIScrollViewContentInsetAdjustmentBehavior fromValue(int value) {
-    if (value != null)
-      return IOSUIScrollViewContentInsetAdjustmentBehavior.values.firstWhere(
-          (element) => element.toValue() == value,
-          orElse: () => null);
+  static IOSUIScrollViewContentInsetAdjustmentBehavior? fromValue(int? value) {
+    if (value != null) {
+      try {
+        return IOSUIScrollViewContentInsetAdjustmentBehavior.values.firstWhere(
+                (element) => element.toValue() == value);
+      } catch (e) {
+        return null;
+      }
+    }
     return null;
   }
 
@@ -4231,19 +4353,19 @@ class IOSUIScrollViewContentInsetAdjustmentBehavior {
 ///SSL certificate info (certificate details) class.
 class SslCertificate {
   ///Name of the entity this certificate is issued by
-  SslCertificateDName issuedBy;
+  SslCertificateDName? issuedBy;
 
   ///Name of the entity this certificate is issued to
-  SslCertificateDName issuedTo;
+  SslCertificateDName? issuedTo;
 
   ///Not-after date from the validity period
-  DateTime validNotAfterDate;
+  DateTime? validNotAfterDate;
 
   ///Not-before date from the validity period
-  DateTime validNotBeforeDate;
+  DateTime? validNotBeforeDate;
 
   ///The original source certificate, if available.
-  X509Certificate x509Certificate;
+  X509Certificate? x509Certificate;
 
   SslCertificate(
       {this.issuedBy,
@@ -4252,10 +4374,10 @@ class SslCertificate {
       this.validNotBeforeDate,
       this.x509Certificate});
 
-  static SslCertificate fromMap(Map<String, dynamic> map) {
-    X509Certificate x509Certificate;
+  static SslCertificate? fromMap(Map<String, dynamic>? map) {
+    X509Certificate? x509Certificate;
     try {
-      x509Certificate = X509Certificate.fromData(data: map["x509Certificate"]);
+      x509Certificate = map != null ? X509Certificate.fromData(data: map["x509Certificate"]) : null;
     } catch (e, stacktrace) {
       print(e);
       print(stacktrace);
@@ -4280,8 +4402,8 @@ class SslCertificate {
     return {
       "issuedBy": issuedBy?.toMap(),
       "issuedTo": issuedTo?.toMap(),
-      "validNotAfterDate": validNotAfterDate.millisecondsSinceEpoch,
-      "validNotBeforeDate": validNotBeforeDate.millisecondsSinceEpoch,
+      "validNotAfterDate": validNotAfterDate?.millisecondsSinceEpoch,
+      "validNotBeforeDate": validNotBeforeDate?.millisecondsSinceEpoch,
       "x509Certificate": x509Certificate?.toMap(),
     };
   }
@@ -4300,19 +4422,19 @@ class SslCertificate {
 class SslCertificateDName {
   ///Common-name (CN) component of the name
   // ignore: non_constant_identifier_names
-  String CName;
+  String? CName;
 
   ///Distinguished name (normally includes CN, O, and OU names)
   // ignore: non_constant_identifier_names
-  String DName;
+  String? DName;
 
   ///Organization (O) component of the name
   // ignore: non_constant_identifier_names
-  String OName;
+  String? OName;
 
   ///Organizational Unit (OU) component of the name
   // ignore: non_constant_identifier_names
-  String UName;
+  String? UName;
 
   SslCertificateDName(
       // ignore: non_constant_identifier_names
@@ -4324,7 +4446,7 @@ class SslCertificateDName {
       // ignore: non_constant_identifier_names
       this.UName = ""});
 
-  static SslCertificateDName fromMap(Map<String, dynamic> map) {
+  static SslCertificateDName? fromMap(Map<String, dynamic>? map) {
     return map != null
         ? SslCertificateDName(
             CName: map["CName"] ?? "",
@@ -4361,12 +4483,12 @@ class LoginRequest {
 
   ///An optional account. If not `null`, the account should be checked against accounts on the device.
   ///If it is a valid account, it should be used to log in the user. This value may be `null`.
-  String account;
+  String? account;
 
   ///Authenticator specific arguments used to log in the user.
   String args;
 
-  LoginRequest({this.realm, this.account, this.args});
+  LoginRequest({required this.realm, this.account, required this.args});
 
   Map<String, dynamic> toMap() {
     return {"realm": realm, "account": account, "args": args};
diff --git a/lib/src/util.dart b/lib/src/util.dart
index 9e30a304..51329067 100644
--- a/lib/src/util.dart
+++ b/lib/src/util.dart
@@ -3,7 +3,7 @@ import 'dart:math';
 import 'package:flutter/material.dart';
 
 class Util {
-  static Color convertColorFromStringRepresentation(String colorValue) {
+  static Color? convertColorFromStringRepresentation(String colorValue) {
     if (colorValue.startsWith("#")) {
       return Util.getColorFromHex(colorValue);
     } else if (colorValue.startsWith("rgb(")) {
@@ -391,7 +391,7 @@ class Util {
         rgbaValues[0], rgbaValues[1], rgbaValues[2], hlsaValues[3]);
   }
 
-  static List<num> hslToRgb(double h, double s, double l) {
+  static List<int> hslToRgb(double h, double s, double l) {
     double r, g, b;
 
     if (s == 0) {
@@ -407,8 +407,8 @@ class Util {
     return rgb;
   }
 
-  static num to255(double v) {
-    return min(255, 256 * v);
+  static int to255(double v) {
+    return min(255, (256 * v).round());
   }
 
   /// Helper method that converts hue to rgb
diff --git a/lib/src/web_storage.dart b/lib/src/web_storage.dart
index dfefc957..657c2ef4 100644
--- a/lib/src/web_storage.dart
+++ b/lib/src/web_storage.dart
@@ -1,7 +1,5 @@
 import 'dart:convert';
 
-import 'package:flutter/foundation.dart';
-
 import 'in_app_webview_controller.dart';
 import 'types.dart';
 
@@ -14,13 +12,13 @@ class WebStorage {
   ///Represents `window.sessionStorage`.
   SessionStorage sessionStorage;
 
-  WebStorage({@required this.localStorage, @required this.sessionStorage});
+  WebStorage({required this.localStorage, required this.sessionStorage});
 }
 
 ///Class that represents a single web storage item of the JavaScript `window.sessionStorage` and `window.localStorage` objects.
 class WebStorageItem {
   ///Item key.
-  String key;
+  String? key;
 
   ///Item value.
   dynamic value;
@@ -47,18 +45,17 @@ class WebStorageItem {
 ///Class that provides methods to manage the JavaScript [Storage](https://developer.mozilla.org/en-US/docs/Web/API/Storage) object.
 ///It is used by [LocalStorage] and [SessionStorage].
 class Storage {
-  InAppWebViewController _controller;
+  late InAppWebViewController _controller;
 
   ///The web storage type: `window.sessionStorage` or `window.localStorage`.
   WebStorageType webStorageType;
 
   Storage(InAppWebViewController controller, this.webStorageType) {
-    assert(controller != null && this.webStorageType != null);
     this._controller = controller;
   }
 
   ///Returns an integer representing the number of data items stored in the Storage object.
-  Future<int> length() async {
+  Future<int?> length() async {
     var result = await _controller.evaluateJavascript(source: """
     window.$webStorageType.length;
     """);
@@ -66,7 +63,7 @@ class Storage {
   }
 
   ///When passed a [key] name and [value], will add that key to the storage, or update that key's value if it already exists.
-  Future<void> setItem({@required String key, @required dynamic value}) async {
+  Future<void> setItem({required String key, required dynamic value}) async {
     var encodedValue = json.encode(value);
     await _controller.evaluateJavascript(source: """
     window.$webStorageType.setItem("$key", ${value is String ? encodedValue : "JSON.stringify($encodedValue)"});
@@ -74,7 +71,7 @@ class Storage {
   }
 
   ///When passed a [key] name, will return that key's value, or `null` if the key does not exist, in the given Storage object.
-  Future<dynamic> getItem({@required String key}) async {
+  Future<dynamic> getItem({required String key}) async {
     var itemValue = await _controller.evaluateJavascript(source: """
     window.$webStorageType.getItem("$key");
     """);
@@ -91,7 +88,7 @@ class Storage {
   }
 
   ///When passed a [key] name, will remove that key from the given Storage object if it exists.
-  Future<void> removeItem({@required String key}) async {
+  Future<void> removeItem({required String key}) async {
     await _controller.evaluateJavascript(source: """
     window.$webStorageType.removeItem("$key");
     """);
@@ -139,7 +136,7 @@ class Storage {
 
   ///When passed a number [index], returns the name of the nth key in a given Storage object.
   ///The order of keys is user-agent defined, so you should not rely on it.
-  Future<String> key({@required int index}) async {
+  Future<String> key({required int index}) async {
     var result = await _controller.evaluateJavascript(source: """
     window.$webStorageType.key($index);
     """);
diff --git a/lib/src/web_storage_manager.dart b/lib/src/web_storage_manager.dart
index df198eeb..6bac0bb6 100755
--- a/lib/src/web_storage_manager.dart
+++ b/lib/src/web_storage_manager.dart
@@ -1,6 +1,5 @@
 import 'dart:async';
 
-import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 import 'types.dart';
@@ -11,7 +10,7 @@ import 'types.dart';
 ///
 ///**NOTE for iOS**: available from iOS 9.0+.
 class WebStorageManager {
-  static WebStorageManager _instance;
+  static WebStorageManager? _instance;
   static const MethodChannel _channel = const MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_webstoragemanager');
 
@@ -20,13 +19,13 @@ class WebStorageManager {
 
   ///Gets the WebStorage manager shared instance.
   static WebStorageManager instance() {
-    return (_instance != null) ? _instance : _init();
+    return (_instance != null) ? _instance! : _init();
   }
 
   static WebStorageManager _init() {
     _channel.setMethodCallHandler(_handleMethod);
     _instance = new WebStorageManager();
-    return _instance;
+    return _instance!;
   }
 
   static Future<dynamic> _handleMethod(MethodCall call) async {}
@@ -63,8 +62,7 @@ class AndroidWebStorageManager {
 
   ///Clears the storage currently being used by both the Application Cache and Web SQL Database APIs by the given [origin].
   ///The origin is specified using its string representation.
-  Future<void> deleteOrigin({@required String origin}) async {
-    assert(origin != null);
+  Future<void> deleteOrigin({required String origin}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("origin", () => origin);
     await WebStorageManager._channel.invokeMethod('deleteOrigin', args);
@@ -73,8 +71,7 @@ class AndroidWebStorageManager {
   ///Gets the storage quota for the Web SQL Database API for the given [origin].
   ///The quota is given in bytes and the origin is specified using its string representation.
   ///Note that a quota is not enforced on a per-origin basis for the Application Cache API.
-  Future<int> getQuotaForOrigin({@required String origin}) async {
-    assert(origin != null);
+  Future<int> getQuotaForOrigin({required String origin}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("origin", () => origin);
     return await WebStorageManager._channel
@@ -83,8 +80,7 @@ class AndroidWebStorageManager {
 
   ///Gets the amount of storage currently being used by both the Application Cache and Web SQL Database APIs by the given [origin].
   ///The amount is given in bytes and the origin is specified using its string representation.
-  Future<int> getUsageForOrigin({@required String origin}) async {
-    assert(origin != null);
+  Future<int> getUsageForOrigin({required String origin}) async {
     Map<String, dynamic> args = <String, dynamic>{};
     args.putIfAbsent("origin", () => origin);
     return await WebStorageManager._channel
@@ -101,8 +97,7 @@ class IOSWebStorageManager {
   ///
   ///[dataTypes] represents the website data types to fetch records for.
   Future<List<IOSWKWebsiteDataRecord>> fetchDataRecords(
-      {@required Set<IOSWKWebsiteDataType> dataTypes}) async {
-    assert(dataTypes != null);
+      {required Set<IOSWKWebsiteDataType> dataTypes}) async {
     List<IOSWKWebsiteDataRecord> recordList = [];
     List<String> dataTypesList = [];
     for (var dataType in dataTypes) {
@@ -116,8 +111,11 @@ class IOSWebStorageManager {
     for (var record in records) {
       List<String> dataTypesString = record["dataTypes"].cast<String>();
       Set<IOSWKWebsiteDataType> dataTypes = Set();
-      for (var dataType in dataTypesString) {
-        dataTypes.add(IOSWKWebsiteDataType.fromValue(dataType));
+      for (var dataTypeValue in dataTypesString) {
+        var dataType = IOSWKWebsiteDataType.fromValue(dataTypeValue);
+        if (dataType != null) {
+          dataTypes.add(dataType);
+        }
       }
       recordList.add(IOSWKWebsiteDataRecord(
           displayName: record["displayName"], dataTypes: dataTypes));
@@ -131,10 +129,8 @@ class IOSWebStorageManager {
   ///
   ///[dataRecords] represents the website data records to delete website data for.
   Future<void> removeDataFor(
-      {@required Set<IOSWKWebsiteDataType> dataTypes,
-      @required List<IOSWKWebsiteDataRecord> dataRecords}) async {
-    assert(dataTypes != null && dataRecords != null);
-
+      {required Set<IOSWKWebsiteDataType> dataTypes,
+      required List<IOSWKWebsiteDataRecord> dataRecords}) async {
     List<String> dataTypesList = [];
     for (var dataType in dataTypes) {
       dataTypesList.add(dataType.toValue());
@@ -157,10 +153,8 @@ class IOSWebStorageManager {
   ///
   ///[date] represents a date. All website data modified after this date will be removed.
   Future<void> removeDataModifiedSince(
-      {@required Set<IOSWKWebsiteDataType> dataTypes,
-      @required DateTime date}) async {
-    assert(dataTypes != null && date != null);
-
+      {required Set<IOSWKWebsiteDataType> dataTypes,
+      required DateTime date}) async {
     List<String> dataTypesList = [];
     for (var dataType in dataTypes) {
       dataTypesList.add(dataType.toValue());
diff --git a/lib/src/webview.dart b/lib/src/webview.dart
index 92d9fb95..78c99419 100644
--- a/lib/src/webview.dart
+++ b/lib/src/webview.dart
@@ -10,17 +10,17 @@ import 'headless_in_app_webview.dart';
 ///Abstract class that represents a WebView. Used by [WebView] and [HeadlessInAppWebView].
 abstract class WebView {
   ///The window id of a [CreateWindowRequest.windowId].
-  final int windowId;
+  final int? windowId;
 
   ///Event fired when the [WebView] is created.
-  final void Function(InAppWebViewController controller) onWebViewCreated;
+  final void Function(InAppWebViewController controller)? onWebViewCreated;
 
   ///Event fired when the [WebView] starts to load an [url].
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onPageStarted(android.webkit.WebView,%20java.lang.String,%20android.graphics.Bitmap)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455621-webview
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String? url)?
       onLoadStart;
 
   ///Event fired when the [WebView] finishes loading an [url].
@@ -28,15 +28,15 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onPageFinished(android.webkit.WebView,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455629-webview
-  final void Function(InAppWebViewController controller, String url) onLoadStop;
+  final void Function(InAppWebViewController controller, String? url)? onLoadStop;
 
   ///Event fired when the [WebView] encounters an error loading an [url].
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedError(android.webkit.WebView,%20int,%20java.lang.String,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455623-webview
-  final void Function(InAppWebViewController controller, String url, int code,
-      String message) onLoadError;
+  final void Function(InAppWebViewController controller, String? url, int code,
+      String message)? onLoadError;
 
   ///Event fired when the [WebView] main page receives an HTTP error.
   ///
@@ -51,20 +51,20 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedHttpError(android.webkit.WebView,%20android.webkit.WebResourceRequest,%20android.webkit.WebResourceResponse)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455643-webview
-  final void Function(InAppWebViewController controller, String url,
-      int statusCode, String description) onLoadHttpError;
+  final void Function(InAppWebViewController controller, String? url,
+      int statusCode, String description)? onLoadHttpError;
 
   ///Event fired when the current [progress] of loading a page is changed.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onProgressChanged(android.webkit.WebView,%20int)
-  final void Function(InAppWebViewController controller, int progress)
+  final void Function(InAppWebViewController controller, int progress)?
       onProgressChanged;
 
   ///Event fired when the [WebView] receives a [ConsoleMessage].
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onConsoleMessage(android.webkit.ConsoleMessage)
   final void Function(
-          InAppWebViewController controller, ConsoleMessage consoleMessage)
+          InAppWebViewController controller, ConsoleMessage consoleMessage)?
       onConsoleMessage;
 
   ///Give the host application a chance to take control when a URL is about to be loaded in the current WebView. This event is not called on the initial load of the WebView.
@@ -82,16 +82,16 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#shouldOverrideUrlLoading(android.webkit.WebView,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455641-webview
-  final Future<ShouldOverrideUrlLoadingAction> Function(
+  final Future<ShouldOverrideUrlLoadingAction?> Function(
           InAppWebViewController controller,
-          ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest)
+          ShouldOverrideUrlLoadingRequest shouldOverrideUrlLoadingRequest)?
       shouldOverrideUrlLoading;
 
   ///Event fired when the [WebView] loads a resource.
   ///
   ///**NOTE**: In order to be able to listen this event, you need to set [InAppWebViewOptions.useOnLoadResource] and [InAppWebViewOptions.javaScriptEnabled] options to `true`.
   final void Function(
-          InAppWebViewController controller, LoadedResource resource)
+          InAppWebViewController controller, LoadedResource resource)?
       onLoadResource;
 
   ///Event fired when the [WebView] scrolls.
@@ -103,7 +103,7 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#onScrollChanged(int,%20int,%20int,%20int)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiscrollviewdelegate/1619392-scrollviewdidscroll
-  final void Function(InAppWebViewController controller, int x, int y)
+  final void Function(InAppWebViewController controller, int x, int y)?
       onScrollChanged;
 
   ///Event fired when [WebView] recognizes a downloadable file.
@@ -116,7 +116,7 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#setDownloadListener(android.webkit.DownloadListener)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455643-webview
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String url)?
       onDownloadStart;
 
   ///Event fired when the [WebView] finds the `custom-scheme` while loading a resource. Here you can handle the url request and return a [CustomSchemeResponse] to load a specific resource encoded to `base64`.
@@ -126,8 +126,8 @@ abstract class WebView {
   ///[url] represents the url of the request.
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkurlschemehandler
-  final Future<CustomSchemeResponse> Function(
-          InAppWebViewController controller, String scheme, String url)
+  final Future<CustomSchemeResponse?> Function(
+          InAppWebViewController controller, String scheme, String url)?
       onLoadResourceCustomScheme;
 
   ///Event fired when the [WebView] requests the host application to create a new window,
@@ -160,8 +160,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onCreateWindow(android.webkit.WebView,%20boolean,%20boolean,%20android.os.Message)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1536907-webview
-  final Future<bool> Function(InAppWebViewController controller,
-      CreateWindowRequest createWindowRequest) onCreateWindow;
+  final Future<bool?> Function(InAppWebViewController controller,
+      CreateWindowRequest createWindowRequest)? onCreateWindow;
 
   ///Event fired when the host application should close the given WebView and remove it from the view system if necessary.
   ///At this point, WebCore has stopped any loading in this window and has removed any cross-scripting ability in javascript.
@@ -169,15 +169,15 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onCloseWindow(android.webkit.WebView)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1537390-webviewdidclose
-  final void Function(InAppWebViewController controller) onCloseWindow;
+  final void Function(InAppWebViewController controller)? onCloseWindow;
 
   ///Event fired when the JavaScript `window` object of the WebView has received focus.
   ///This is the result of the `focus` JavaScript event applied to the `window` object.
-  final void Function(InAppWebViewController controller) onWindowFocus;
+  final void Function(InAppWebViewController controller)? onWindowFocus;
 
   ///Event fired when the JavaScript `window` object of the WebView has lost focus.
   ///This is the result of the `blur` JavaScript event applied to the `window` object.
-  final void Function(InAppWebViewController controller) onWindowBlur;
+  final void Function(InAppWebViewController controller)? onWindowBlur;
 
   ///Event fired when javascript calls the `alert()` method to display an alert dialog.
   ///If [JsAlertResponse.handledByClient] is `true`, the webview will assume that the client will handle the dialog.
@@ -187,8 +187,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsAlert(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20android.webkit.JsResult)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1537406-webview
-  final Future<JsAlertResponse> Function(
-          InAppWebViewController controller, JsAlertRequest jsAlertRequest)
+  final Future<JsAlertResponse?> Function(
+          InAppWebViewController controller, JsAlertRequest jsAlertRequest)?
       onJsAlert;
 
   ///Event fired when javascript calls the `confirm()` method to display a confirm dialog.
@@ -199,8 +199,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsConfirm(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20android.webkit.JsResult)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1536489-webview
-  final Future<JsConfirmResponse> Function(
-          InAppWebViewController controller, JsConfirmRequest jsConfirmRequest)
+  final Future<JsConfirmResponse?> Function(
+          InAppWebViewController controller, JsConfirmRequest jsConfirmRequest)?
       onJsConfirm;
 
   ///Event fired when javascript calls the `prompt()` method to display a prompt dialog.
@@ -211,8 +211,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsPrompt(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20android.webkit.JsPromptResult)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wkuidelegate/1538086-webview
-  final Future<JsPromptResponse> Function(
-          InAppWebViewController controller, JsPromptRequest jsPromptRequest)
+  final Future<JsPromptResponse?> Function(
+          InAppWebViewController controller, JsPromptRequest jsPromptRequest)?
       onJsPrompt;
 
   ///Event fired when the WebView received an HTTP authentication request. The default behavior is to cancel the request.
@@ -222,8 +222,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedHttpAuthRequest(android.webkit.WebView,%20android.webkit.HttpAuthHandler,%20java.lang.String,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455638-webview
-  final Future<HttpAuthResponse> Function(
-          InAppWebViewController controller, HttpAuthChallenge challenge)
+  final Future<HttpAuthResponse?> Function(
+          InAppWebViewController controller, HttpAuthChallenge challenge)?
       onReceivedHttpAuthRequest;
 
   ///Event fired when the WebView need to perform server trust authentication (certificate validation).
@@ -234,8 +234,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedSslError(android.webkit.WebView,%20android.webkit.SslErrorHandler,%20android.net.http.SslError)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455638-webview
-  final Future<ServerTrustAuthResponse> Function(
-          InAppWebViewController controller, ServerTrustChallenge challenge)
+  final Future<ServerTrustAuthResponse?> Function(
+          InAppWebViewController controller, ServerTrustChallenge challenge)?
       onReceivedServerTrustAuthRequest;
 
   ///Notify the host application to handle an SSL client certificate request.
@@ -248,8 +248,8 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedClientCertRequest(android.webkit.WebView,%20android.webkit.ClientCertRequest)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455638-webview
-  final Future<ClientCertResponse> Function(
-          InAppWebViewController controller, ClientCertChallenge challenge)
+  final Future<ClientCertResponse?> Function(
+          InAppWebViewController controller, ClientCertChallenge challenge)?
       onReceivedClientCertRequest;
 
   ///Event fired as find-on-page operations progress.
@@ -263,7 +263,7 @@ abstract class WebView {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebView#setFindListener(android.webkit.WebView.FindListener)
   final void Function(InAppWebViewController controller, int activeMatchOrdinal,
-      int numberOfMatches, bool isDoneCounting) onFindResultReceived;
+      int numberOfMatches, bool isDoneCounting)? onFindResultReceived;
 
   ///Event fired when an `XMLHttpRequest` is sent to a server.
   ///It gives the host application a chance to take control over the request before sending it.
@@ -275,8 +275,8 @@ abstract class WebView {
   ///can inject javascript code right after the document element is created but before any other content is loaded, in Android the javascript code
   ///used to intercept ajax requests is loaded as soon as possible so it won't be instantaneous as iOS but just after some milliseconds (< ~100ms).
   ///Inside the `window.addEventListener("flutterInAppWebViewPlatformReady")` event, the ajax requests will be intercept for sure.
-  final Future<AjaxRequest> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequest?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       shouldInterceptAjaxRequest;
 
   ///Event fired whenever the `readyState` attribute of an `XMLHttpRequest` changes.
@@ -289,8 +289,8 @@ abstract class WebView {
   ///can inject javascript code right after the document element is created but before any other content is loaded, in Android the javascript code
   ///used to intercept ajax requests is loaded as soon as possible so it won't be instantaneous as iOS but just after some milliseconds (< ~100ms).
   ///Inside the `window.addEventListener("flutterInAppWebViewPlatformReady")` event, the ajax requests will be intercept for sure.
-  final Future<AjaxRequestAction> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequestAction?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       onAjaxReadyStateChange;
 
   ///Event fired as an `XMLHttpRequest` progress.
@@ -303,8 +303,8 @@ abstract class WebView {
   ///can inject javascript code right after the document element is created but before any other content is loaded, in Android the javascript code
   ///used to intercept ajax requests is loaded as soon as possible so it won't be instantaneous as iOS but just after some milliseconds (< ~100ms).
   ///Inside the `window.addEventListener("flutterInAppWebViewPlatformReady")` event, the ajax requests will be intercept for sure.
-  final Future<AjaxRequestAction> Function(
-          InAppWebViewController controller, AjaxRequest ajaxRequest)
+  final Future<AjaxRequestAction?> Function(
+          InAppWebViewController controller, AjaxRequest ajaxRequest)?
       onAjaxProgress;
 
   ///Event fired when a request is sent to a server through [Fetch API](https://developer.mozilla.org/it/docs/Web/API/Fetch_API).
@@ -317,8 +317,8 @@ abstract class WebView {
   ///can inject javascript code right after the document element is created but before any other content is loaded, in Android the javascript code
   ///used to intercept fetch requests is loaded as soon as possible so it won't be instantaneous as iOS but just after some milliseconds (< ~100ms).
   ///Inside the `window.addEventListener("flutterInAppWebViewPlatformReady")` event, the fetch requests will be intercept for sure.
-  final Future<FetchRequest> Function(
-          InAppWebViewController controller, FetchRequest fetchRequest)
+  final Future<FetchRequest?> Function(
+          InAppWebViewController controller, FetchRequest fetchRequest)?
       shouldInterceptFetchRequest;
 
   ///Event fired when the host application updates its visited links database.
@@ -332,7 +332,7 @@ abstract class WebView {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#doUpdateVisitedHistory(android.webkit.WebView,%20java.lang.String,%20boolean)
   final void Function(
-          InAppWebViewController controller, String url, bool androidIsReload)
+          InAppWebViewController controller, String? url, bool? androidIsReload)?
       onUpdateVisitedHistory;
 
   ///Event fired when `window.print()` is called from JavaScript side.
@@ -340,7 +340,7 @@ abstract class WebView {
   ///[url] represents the url on which is called.
   ///
   ///**NOTE**: available on Android 21+.
-  final void Function(InAppWebViewController controller, String url) onPrint;
+  final void Function(InAppWebViewController controller, String? url)? onPrint;
 
   ///Event fired when an HTML element of the webview has been clicked and held.
   ///
@@ -350,21 +350,21 @@ abstract class WebView {
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uilongpressgesturerecognizer
   final void Function(InAppWebViewController controller,
-      InAppWebViewHitTestResult hitTestResult) onLongPressHitTestResult;
+      InAppWebViewHitTestResult hitTestResult)? onLongPressHitTestResult;
 
   ///Event fired when the current page has entered full screen mode.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onShowCustomView(android.view.View,%20android.webkit.WebChromeClient.CustomViewCallback)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiwindow/1621621-didbecomevisiblenotification
-  final void Function(InAppWebViewController controller) onEnterFullscreen;
+  final void Function(InAppWebViewController controller)? onEnterFullscreen;
 
   ///Event fired when the current page has exited full screen mode.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onHideCustomView()
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/uikit/uiwindow/1621617-didbecomehiddennotification
-  final void Function(InAppWebViewController controller) onExitFullscreen;
+  final void Function(InAppWebViewController controller)? onExitFullscreen;
 
   ///Called when the web view begins to receive web content.
   ///
@@ -376,7 +376,7 @@ abstract class WebView {
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onPageCommitVisible(android.webkit.WebView,%20java.lang.String)
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455635-webview
-  final void Function(InAppWebViewController controller, String url)
+  final void Function(InAppWebViewController controller, String? url)?
       onPageCommitVisible;
 
   ///Event fired when a change in the document title occurred.
@@ -384,7 +384,7 @@ abstract class WebView {
   ///[title] represents the string containing the new title of the document.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onReceivedTitle(android.webkit.WebView,%20java.lang.String)
-  final void Function(InAppWebViewController controller, String title)
+  final void Function(InAppWebViewController controller, String? title)?
       onTitleChanged;
 
   ///Event fired when the webview notifies that a loading URL has been flagged by Safe Browsing.
@@ -397,8 +397,8 @@ abstract class WebView {
   ///**NOTE**: available only on Android 27+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onSafeBrowsingHit(android.webkit.WebView,%20android.webkit.WebResourceRequest,%20int,%20android.webkit.SafeBrowsingResponse)
-  final Future<SafeBrowsingResponse> Function(InAppWebViewController controller,
-      String url, SafeBrowsingThreat threatType) androidOnSafeBrowsingHit;
+  final Future<SafeBrowsingResponse?> Function(InAppWebViewController controller,
+      String url, SafeBrowsingThreat? threatType)? androidOnSafeBrowsingHit;
 
   ///Event fired when the WebView is requesting permission to access the specified resources and the permission currently isn't granted or denied.
   ///
@@ -409,10 +409,10 @@ abstract class WebView {
   ///**NOTE**: available only on Android 23+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onPermissionRequest(android.webkit.PermissionRequest)
-  final Future<PermissionRequestResponse> Function(
+  final Future<PermissionRequestResponse?> Function(
       InAppWebViewController controller,
       String origin,
-      List<String> resources) androidOnPermissionRequest;
+      List<String> resources)? androidOnPermissionRequest;
 
   ///Event that notifies the host application that web content from the specified origin is attempting to use the Geolocation API, but no permission state is currently set for that origin.
   ///Note that for applications targeting Android N and later SDKs (API level > `Build.VERSION_CODES.M`) this method is only called for requests originating from secure origins such as https.
@@ -423,8 +423,8 @@ abstract class WebView {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onGeolocationPermissionsShowPrompt(java.lang.String,%20android.webkit.GeolocationPermissions.Callback)
-  final Future<GeolocationPermissionShowPromptResponse> Function(
-          InAppWebViewController controller, String origin)
+  final Future<GeolocationPermissionShowPromptResponse?> Function(
+          InAppWebViewController controller, String origin)?
       androidOnGeolocationPermissionsShowPrompt;
 
   ///Notify the host application that a request for Geolocation permissions, made with a previous call to [androidOnGeolocationPermissionsShowPrompt] has been canceled.
@@ -433,7 +433,7 @@ abstract class WebView {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onGeolocationPermissionsHidePrompt()
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       androidOnGeolocationPermissionsHidePrompt;
 
   ///Notify the host application of a resource request and allow the application to return the data.
@@ -453,8 +453,8 @@ abstract class WebView {
   ///**Official Android API**:
   ///- https://developer.android.com/reference/android/webkit/WebViewClient#shouldInterceptRequest(android.webkit.WebView,%20android.webkit.WebResourceRequest)
   ///- https://developer.android.com/reference/android/webkit/WebViewClient#shouldInterceptRequest(android.webkit.WebView,%20java.lang.String)
-  final Future<WebResourceResponse> Function(
-          InAppWebViewController controller, WebResourceRequest request)
+  final Future<WebResourceResponse?> Function(
+          InAppWebViewController controller, WebResourceRequest request)?
       androidShouldInterceptRequest;
 
   ///Event called when the renderer currently associated with the WebView becomes unresponsive as a result of a long running blocking task such as the execution of JavaScript.
@@ -475,8 +475,8 @@ abstract class WebView {
   ///**NOTE**: available only on Android 29+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewRenderProcessClient#onRenderProcessUnresponsive(android.webkit.WebView,%20android.webkit.WebViewRenderProcess)
-  final Future<WebViewRenderProcessAction> Function(
-          InAppWebViewController controller, String url)
+  final Future<WebViewRenderProcessAction?> Function(
+          InAppWebViewController controller, String? url)?
       androidOnRenderProcessUnresponsive;
 
   ///Event called once when an unresponsive renderer currently associated with the WebView becomes responsive.
@@ -490,8 +490,8 @@ abstract class WebView {
   ///**NOTE**: available only on Android 29+.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewRenderProcessClient#onRenderProcessResponsive(android.webkit.WebView,%20android.webkit.WebViewRenderProcess)
-  final Future<WebViewRenderProcessAction> Function(
-          InAppWebViewController controller, String url)
+  final Future<WebViewRenderProcessAction?> Function(
+          InAppWebViewController controller, String? url)?
       androidOnRenderProcessResponsive;
 
   ///Event fired when the given WebView's render process has exited.
@@ -504,7 +504,7 @@ abstract class WebView {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onRenderProcessGone(android.webkit.WebView,%20android.webkit.RenderProcessGoneDetail)
   final void Function(
-          InAppWebViewController controller, RenderProcessGoneDetail detail)
+          InAppWebViewController controller, RenderProcessGoneDetail detail)?
       androidOnRenderProcessGone;
 
   ///As the host application if the browser should resend data as the requested page was a result of a POST. The default is to not resend the data.
@@ -512,8 +512,8 @@ abstract class WebView {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onFormResubmission(android.webkit.WebView,%20android.os.Message,%20android.os.Message)
-  final Future<FormResubmissionAction> Function(
-      InAppWebViewController controller, String url) androidOnFormResubmission;
+  final Future<FormResubmissionAction?> Function(
+      InAppWebViewController controller, String? url)? androidOnFormResubmission;
 
   ///Event fired when the scale applied to the WebView has changed.
   ///
@@ -525,7 +525,7 @@ abstract class WebView {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onScaleChanged(android.webkit.WebView,%20float,%20float)
   final void Function(
-          InAppWebViewController controller, double oldScale, double newScale)
+          InAppWebViewController controller, double oldScale, double newScale)?
       androidOnScaleChanged;
 
   ///Event fired when there is a request to display and focus for this WebView.
@@ -534,7 +534,7 @@ abstract class WebView {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onRequestFocus(android.webkit.WebView)
-  final void Function(InAppWebViewController controller) androidOnRequestFocus;
+  final void Function(InAppWebViewController controller)? androidOnRequestFocus;
 
   ///Event fired when there is new favicon for the current page.
   ///
@@ -543,7 +543,7 @@ abstract class WebView {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onReceivedIcon(android.webkit.WebView,%20android.graphics.Bitmap)
-  final void Function(InAppWebViewController controller, Uint8List icon)
+  final void Function(InAppWebViewController controller, Uint8List icon)?
       androidOnReceivedIcon;
 
   ///Event fired when there is an url for an apple-touch-icon.
@@ -556,7 +556,7 @@ abstract class WebView {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onReceivedTouchIconUrl(android.webkit.WebView,%20java.lang.String,%20boolean)
   final void Function(
-          InAppWebViewController controller, String url, bool precomposed)
+          InAppWebViewController controller, String url, bool precomposed)?
       androidOnReceivedTouchIconUrl;
 
   ///Event fired when the client should display a dialog to confirm navigation away from the current page.
@@ -572,9 +572,9 @@ abstract class WebView {
   ///**NOTE**: available only on Android.
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebChromeClient#onJsBeforeUnload(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20android.webkit.JsResult)
-  final Future<JsBeforeUnloadResponse> Function(
+  final Future<JsBeforeUnloadResponse?> Function(
       InAppWebViewController controller,
-      JsBeforeUnloadRequest jsBeforeUnloadRequest) androidOnJsBeforeUnload;
+      JsBeforeUnloadRequest jsBeforeUnloadRequest)? androidOnJsBeforeUnload;
 
   ///Event fired when a request to automatically log in the user has been processed.
   ///
@@ -584,7 +584,7 @@ abstract class WebView {
   ///
   ///**Official Android API**: https://developer.android.com/reference/android/webkit/WebViewClient#onReceivedLoginRequest(android.webkit.WebView,%20java.lang.String,%20java.lang.String,%20java.lang.String)
   final void Function(
-          InAppWebViewController controller, LoginRequest loginRequest)
+          InAppWebViewController controller, LoginRequest loginRequest)?
       androidOnReceivedLoginRequest;
 
   ///Invoked when the web view's web content process is terminated.
@@ -592,7 +592,7 @@ abstract class WebView {
   ///**NOTE**: available only on iOS.
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455639-webviewwebcontentprocessdidtermi
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       iosOnWebContentProcessDidTerminate;
 
   ///Called when a web view receives a server redirect.
@@ -600,26 +600,26 @@ abstract class WebView {
   ///**NOTE**: available only on iOS.
   ///
   ///**Official iOS API**: https://developer.apple.com/documentation/webkit/wknavigationdelegate/1455627-webview
-  final void Function(InAppWebViewController controller)
+  final void Function(InAppWebViewController controller)?
       iosOnDidReceiveServerRedirectForProvisionalNavigation;
 
   ///Initial url that will be loaded.
-  final String initialUrl;
+  final String? initialUrl;
 
   ///Initial asset file that will be loaded. See [InAppWebViewController.loadFile] for explanation.
-  final String initialFile;
+  final String? initialFile;
 
   ///Initial [InAppWebViewInitialData] that will be loaded.
-  final InAppWebViewInitialData initialData;
+  final InAppWebViewInitialData? initialData;
 
   ///Initial headers that will be used.
-  final Map<String, String> initialHeaders;
+  final Map<String, String>? initialHeaders;
 
   ///Initial options that will be used.
-  final InAppWebViewGroupOptions initialOptions;
+  final InAppWebViewGroupOptions? initialOptions;
 
   ///Context menu which contains custom menu items to be shown when [ContextMenu] is presented.
-  final ContextMenu contextMenu;
+  final ContextMenu? contextMenu;
 
   WebView(
       {this.windowId,
diff --git a/lib/src/webview_options.dart b/lib/src/webview_options.dart
index 9391de7b..3a6160f4 100755
--- a/lib/src/webview_options.dart
+++ b/lib/src/webview_options.dart
@@ -14,7 +14,7 @@ class WebViewOptions {
   }
 
   static WebViewOptions fromMap(Map<String, dynamic> map) {
-    return null;
+    return new WebViewOptions();
   }
 
   WebViewOptions copy() {
@@ -37,7 +37,7 @@ class BrowserOptions {
   }
 
   static BrowserOptions fromMap(Map<String, dynamic> map) {
-    return null;
+    return new BrowserOptions();
   }
 
   BrowserOptions copy() {
@@ -60,7 +60,7 @@ class ChromeSafariBrowserOptions {
   }
 
   static ChromeSafariBrowserOptions fromMap(Map<String, dynamic> map) {
-    return null;
+    return new ChromeSafariBrowserOptions();
   }
 
   ChromeSafariBrowserOptions copy() {
@@ -105,12 +105,6 @@ class InAppWebViewOptions
   ///Set to `true` to enable JavaScript. The default value is `true`.
   bool javaScriptEnabled;
 
-  ///Enables debugging of web contents (HTML / CSS / JavaScript) loaded into any WebViews of this application.
-  ///This flag can be enabled in order to facilitate debugging of web layouts and JavaScript code running inside WebViews. The default is `false`.
-  ///
-  ///**NOTE**: on iOS the debugging mode is always enabled.
-  bool debuggingEnabled;
-
   ///Set to `true` to allow JavaScript open windows without user interaction. The default value is `false`.
   bool javaScriptCanOpenWindowsAutomatically;
 
@@ -120,7 +114,7 @@ class InAppWebViewOptions
   bool mediaPlaybackRequiresUserGesture;
 
   ///Sets the minimum font size. The default value is `8` for Android, `0` for iOS.
-  int minimumFontSize;
+  int? minimumFontSize;
 
   ///Define whether the vertical scrollbar should be drawn or not. The default value is `true`.
   bool verticalScrollBarEnabled;
@@ -141,7 +135,7 @@ class InAppWebViewOptions
   ///Sets the content mode that the WebView needs to use when loading and rendering a webpage. The default value is [UserPreferredContentMode.RECOMMENDED].
   ///
   ///**NOTE**: available on iOS 13.0+.
-  UserPreferredContentMode preferredContentMode;
+  UserPreferredContentMode? preferredContentMode;
 
   ///Set to `true` to be able to listen at the [shouldInterceptAjaxRequest] event. The default value is `false`.
   bool useShouldInterceptAjaxRequest;
@@ -152,6 +146,8 @@ class InAppWebViewOptions
   ///Set to `true` to open a browser window with incognito mode. The default value is `false`.
   ///
   ///**NOTE**: available on iOS 9.0+.
+  ///On Android, by setting this option to `true`, it will clear all the cookies of all WebView instances,
+  ///because there isn't any way to make the website data store non-persistent for the specific WebView instance such as on iOS.
   bool incognito;
 
   ///Sets whether WebView should use browser caching. The default value is `true`.
@@ -182,7 +178,6 @@ class InAppWebViewOptions
       this.userAgent = "",
       this.applicationNameForUserAgent = "",
       this.javaScriptEnabled = true,
-      this.debuggingEnabled = false,
       this.javaScriptCanOpenWindowsAutomatically = false,
       this.mediaPlaybackRequiresUserGesture = true,
       this.minimumFontSize,
@@ -221,7 +216,6 @@ class InAppWebViewOptions
       "userAgent": userAgent,
       "applicationNameForUserAgent": applicationNameForUserAgent,
       "javaScriptEnabled": javaScriptEnabled,
-      "debuggingEnabled": debuggingEnabled,
       "javaScriptCanOpenWindowsAutomatically":
           javaScriptCanOpenWindowsAutomatically,
       "mediaPlaybackRequiresUserGesture": mediaPlaybackRequiresUserGesture,
@@ -244,7 +238,7 @@ class InAppWebViewOptions
 
   static InAppWebViewOptions fromMap(Map<String, dynamic> map) {
     List<ContentBlocker> contentBlockers = [];
-    List<dynamic> contentBlockersMapList = map["contentBlockers"];
+    List<dynamic>? contentBlockersMapList = map["contentBlockers"];
     if (contentBlockersMapList != null) {
       contentBlockersMapList.forEach((contentBlocker) {
         contentBlockers.add(ContentBlocker.fromMap(
@@ -261,7 +255,6 @@ class InAppWebViewOptions
     options.userAgent = map["userAgent"];
     options.applicationNameForUserAgent = map["applicationNameForUserAgent"];
     options.javaScriptEnabled = map["javaScriptEnabled"];
-    options.debuggingEnabled = map["debuggingEnabled"];
     options.javaScriptCanOpenWindowsAutomatically =
         map["javaScriptCanOpenWindowsAutomatically"];
     options.mediaPlaybackRequiresUserGesture =
@@ -339,7 +332,7 @@ class AndroidInAppWebViewOptions
   ///Configures the WebView's behavior when a secure origin attempts to load a resource from an insecure origin.
   ///
   ///**NOTE**: available on Android 21+.
-  AndroidMixedContentMode mixedContentMode;
+  AndroidMixedContentMode? mixedContentMode;
 
   ///Enables or disables content URL access within WebView. Content URL access allows WebView to load content from a content provider installed in the system. The default value is `true`.
   bool allowContentAccess;
@@ -360,7 +353,7 @@ class AndroidInAppWebViewOptions
 
   ///Sets the path to the Application Caches files. In order for the Application Caches API to be enabled, this option must be set a path to which the application can write.
   ///This option is used one time: repeated calls are ignored.
-  String appCachePath;
+  String? appCachePath;
 
   ///Sets whether the WebView should not load image resources from the network (resources accessed via http and https URI schemes). The default value is `false`.
   bool blockNetworkImage;
@@ -370,7 +363,7 @@ class AndroidInAppWebViewOptions
 
   ///Overrides the way the cache is used. The way the cache is used is based on the navigation type. For a normal page load, the cache is checked and content is re-validated as needed.
   ///When navigating back, content is not revalidated, instead the content is just retrieved from the cache. The default value is [AndroidCacheMode.LOAD_DEFAULT].
-  AndroidCacheMode cacheMode;
+  AndroidCacheMode? cacheMode;
 
   ///Sets the cursive font family name. The default value is `"cursive"`.
   String cursiveFontFamily;
@@ -387,7 +380,7 @@ class AndroidInAppWebViewOptions
   ///Disables the action mode menu items according to menuItems flag.
   ///
   ///**NOTE**: available on Android 24+.
-  AndroidActionModeMenuItem disabledActionModeMenuItems;
+  AndroidActionModeMenuItem? disabledActionModeMenuItems;
 
   ///Sets the fantasy font family name. The default value is `"fantasy"`.
   String fantasyFontFamily;
@@ -398,13 +391,13 @@ class AndroidInAppWebViewOptions
   ///Set the force dark mode for this WebView. The default value is [AndroidForceDark.FORCE_DARK_OFF].
   ///
   ///**NOTE**: available on Android 29+.
-  AndroidForceDark forceDark;
+  AndroidForceDark? forceDark;
 
   ///Sets whether Geolocation API is enabled. The default value is `true`.
   bool geolocationEnabled;
 
   ///Sets the underlying layout algorithm. This will cause a re-layout of the WebView.
-  AndroidLayoutAlgorithm layoutAlgorithm;
+  AndroidLayoutAlgorithm? layoutAlgorithm;
 
   ///Sets whether the WebView loads pages in overview mode, that is, zooms out the content to fit on screen by width.
   ///This setting is taken into account when the content width is greater than the width of the WebView control, for example, when [useWideViewPort] is enabled.
@@ -468,7 +461,7 @@ class AndroidInAppWebViewOptions
 
   ///Regular expression used by [shouldOverrideUrlLoading] event to cancel navigation requests for frames that are not the main frame.
   ///If the url request of a subframe matches the regular expression, then the request of that subframe is canceled.
-  String regexToCancelSubFramesLoading;
+  String? regexToCancelSubFramesLoading;
 
   ///Set to `true` to enable Flutter's new Hybrid Composition. The default value is `false`.
   ///Hybrid Composition is supported starting with Flutter v1.20+.
@@ -486,11 +479,11 @@ class AndroidInAppWebViewOptions
   ///Sets the WebView's over-scroll mode.
   ///Setting the over-scroll mode of a WebView will have an effect only if the WebView is capable of scrolling.
   ///The default value is [AndroidOverScrollMode.OVER_SCROLL_IF_CONTENT_SCROLLS].
-  AndroidOverScrollMode overScrollMode;
+  AndroidOverScrollMode? overScrollMode;
 
   ///Informs WebView of the network state.
   ///This is used to set the JavaScript property `window.navigator.isOnline` and generates the online/offline event as specified in HTML5, sec. 5.7.7.
-  bool networkAvailable;
+  bool? networkAvailable;
 
   ///Specifies the style of the scrollbars. The scrollbars can be overlaid or inset.
   ///When inset, they add to the padding of the view. And the scrollbars can be drawn inside the padding area or on the edge of the view.
@@ -498,28 +491,28 @@ class AndroidInAppWebViewOptions
   ///you can use SCROLLBARS_INSIDE_OVERLAY or SCROLLBARS_INSIDE_INSET. If you want them to appear at the edge of the view, ignoring the padding,
   ///then you can use SCROLLBARS_OUTSIDE_OVERLAY or SCROLLBARS_OUTSIDE_INSET.
   ///The default value is [AndroidScrollBarStyle.SCROLLBARS_INSIDE_OVERLAY].
-  AndroidScrollBarStyle scrollBarStyle;
+  AndroidScrollBarStyle? scrollBarStyle;
 
   ///Sets the position of the vertical scroll bar.
   ///The default value is [AndroidVerticalScrollbarPosition.SCROLLBAR_POSITION_DEFAULT].
-  AndroidVerticalScrollbarPosition verticalScrollbarPosition;
+  AndroidVerticalScrollbarPosition? verticalScrollbarPosition;
 
   ///Defines the delay in milliseconds that a scrollbar waits before fade out.
-  int scrollBarDefaultDelayBeforeFade;
+  int? scrollBarDefaultDelayBeforeFade;
 
   ///Defines whether scrollbars will fade when the view is not scrolling.
   ///The default value is `true`.
   bool scrollbarFadingEnabled;
 
   ///Defines the scrollbar fade duration in milliseconds.
-  int scrollBarFadeDuration;
+  int? scrollBarFadeDuration;
 
   ///Sets the renderer priority policy for this WebView.
-  RendererPriorityPolicy rendererPriorityPolicy;
+  RendererPriorityPolicy? rendererPriorityPolicy;
 
   ///Sets whether the default Android error page should be disabled.
   ///The default value is `false`.
-  bool disableDefaultErrorPage;
+  bool? disableDefaultErrorPage;
 
   AndroidInAppWebViewOptions({
     this.textZoom = 100,
@@ -899,8 +892,11 @@ class IOSInAppWebViewOptions
     List<IOSWKDataDetectorTypes> dataDetectorTypes = [];
     List<String> dataDetectorTypesList =
         List<String>.from(map["dataDetectorTypes"] ?? []);
-    dataDetectorTypesList.forEach((dataDetectorType) {
-      dataDetectorTypes.add(IOSWKDataDetectorTypes.fromValue(dataDetectorType));
+    dataDetectorTypesList.forEach((dataDetectorTypeValue) {
+      var dataDetectorType = IOSWKDataDetectorTypes.fromValue(dataDetectorTypeValue);
+      if (dataDetectorType != null) {
+        dataDetectorTypes.add(dataDetectorType);
+      }
     });
 
     IOSInAppWebViewOptions options = IOSInAppWebViewOptions();
@@ -920,7 +916,7 @@ class IOSInAppWebViewOptions
     options.isFraudulentWebsiteWarningEnabled =
         map["isFraudulentWebsiteWarningEnabled"];
     options.selectionGranularity =
-        IOSWKSelectionGranularity.fromValue(map["selectionGranularity"]);
+        IOSWKSelectionGranularity.fromValue(map["selectionGranularity"])!;
     options.dataDetectorTypes = dataDetectorTypes;
     options.sharedCookiesEnabled = map["sharedCookiesEnabled"];
     options.automaticallyAdjustsScrollIndicatorInsets =
@@ -928,7 +924,7 @@ class IOSInAppWebViewOptions
     options.accessibilityIgnoresInvertColors =
         map["accessibilityIgnoresInvertColors"];
     options.decelerationRate =
-        IOSUIScrollViewDecelerationRate.fromValue(map["decelerationRate"]);
+        IOSUIScrollViewDecelerationRate.fromValue(map["decelerationRate"])!;
     options.alwaysBounceVertical = map["alwaysBounceVertical"];
     options.alwaysBounceHorizontal = map["alwaysBounceHorizontal"];
     options.scrollsToTop = map["scrollsToTop"];
@@ -937,7 +933,7 @@ class IOSInAppWebViewOptions
     options.minimumZoomScale = map["minimumZoomScale"];
     options.contentInsetAdjustmentBehavior =
         IOSUIScrollViewContentInsetAdjustmentBehavior.fromValue(
-            map["contentInsetAdjustmentBehavior"]);
+            map["contentInsetAdjustmentBehavior"])!;
     return options;
   }
 
@@ -1127,9 +1123,9 @@ class IOSInAppBrowserOptions implements BrowserOptions, IosOptions {
     options.closeButtonCaption = map["closeButtonCaption"];
     options.closeButtonColor = map["closeButtonColor"];
     options.presentationStyle =
-        IOSUIModalPresentationStyle.fromValue(map["presentationStyle"]);
+        IOSUIModalPresentationStyle.fromValue(map["presentationStyle"])!;
     options.transitionStyle =
-        IOSUIModalTransitionStyle.fromValue(map["transitionStyle"]);
+        IOSUIModalTransitionStyle.fromValue(map["transitionStyle"])!;
     options.spinner = map["spinner"];
     return options;
   }
@@ -1173,7 +1169,7 @@ class AndroidChromeCustomTabsOptions
   ///value of null, all components in all applications will considered.
   ///If non-null, the Intent can only match the components in the given
   ///application package.
-  String packageName;
+  String? packageName;
 
   ///Set to `true` to enable Keep Alive. The default value is `false`.
   bool keepAliveEnabled;
@@ -1285,13 +1281,13 @@ class IOSSafariOptions implements ChromeSafariBrowserOptions, IosOptions {
     options.entersReaderIfAvailable = map["entersReaderIfAvailable"];
     options.barCollapsingEnabled = map["barCollapsingEnabled"];
     options.dismissButtonStyle =
-        IOSSafariDismissButtonStyle.fromValue(map["dismissButtonStyle"]);
+        IOSSafariDismissButtonStyle.fromValue(map["dismissButtonStyle"])!;
     options.preferredBarTintColor = map["preferredBarTintColor"];
     options.preferredControlTintColor = map["preferredControlTintColor"];
     options.presentationStyle =
-        IOSUIModalPresentationStyle.fromValue(map["presentationStyle"]);
+        IOSUIModalPresentationStyle.fromValue(map["presentationStyle"])!;
     options.transitionStyle =
-        IOSUIModalTransitionStyle.fromValue(map["transitionStyle"]);
+        IOSUIModalTransitionStyle.fromValue(map["transitionStyle"])!;
     return options;
   }
 
diff --git a/nodejs_server_test_auth_basic_and_ssl/index.js b/nodejs_server_test_auth_basic_and_ssl/index.js
index 516fbd33..02741082 100755
--- a/nodejs_server_test_auth_basic_and_ssl/index.js
+++ b/nodejs_server_test_auth_basic_and_ssl/index.js
@@ -168,7 +168,6 @@ app.post("/test-ajax-post", (req, res) => {
   res.send(JSON.stringify({
     "firstname": req.body.firstname,
     "lastname": req.body.lastname,
-    "fullname": req.body.firstname + " " + req.body.lastname,
   }))
   res.end()
 })
diff --git a/pubspec.yaml b/pubspec.yaml
index 88111d5a..b12043fb 100755
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,17 +1,22 @@
 name: flutter_inappwebview
 description: A Flutter plugin that allows you to add an inline webview, to use an headless webview, and to open an in-app browser window.
-version: 5.0.0
+version: 5.0.0-nullsafety.0
 homepage: https://github.com/pichillilorenzo/flutter_inappwebview
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
-  flutter: ">=1.12.13+hotfix.5"
+  sdk: ">=2.12.0-0 <3.0.0"
+  flutter: ">=1.22.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  uuid: ^2.0.0
-  mime: ^0.9.6+2
+  uuid: ^3.0.0-nullsafety.0
+  mime: ^1.0.0-nullsafety.0
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  pedantic: ^1.10.0-nullsafety.1
 
 # For information on the generic Dart part of this file, see the
 # following page: https://www.dartlang.org/tools/pub/pubspec
diff --git a/test.sh b/test.sh
index d9e3f74a..5ed217fc 100755
--- a/test.sh
+++ b/test.sh
@@ -1,4 +1,6 @@
 #!/bin/bash
+# flutter clean && flutter run -t ./lib/main.dart -d 'iPhone di Lorenzo' --debug --no-sound-null-safety
+
 # on linux/macOS local IP can be found using $(ipconfig getifaddr en0)
 export NODE_SERVER_IP=$1
 dart tool/env.dart
@@ -7,5 +9,5 @@ node index.js &
 flutter clean
 cd ../example
 flutter clean
-flutter driver -t test_driver/app.dart
+flutter driver --driver=test_driver/integration_test.dart --target=integration_test/webview_flutter_test.dart
 kill $(jobs -p)
\ No newline at end of file
diff --git a/tool/env.dart b/tool/env.dart
index cb1ed0e1..a1123373 100755
--- a/tool/env.dart
+++ b/tool/env.dart
@@ -7,6 +7,6 @@ Future<void> main() async {
     'NODE_SERVER_IP': Platform.environment['NODE_SERVER_IP'],
   };
 
-  final filename = 'example/test_driver/.env.dart';
+  final filename = 'example/integration_test/.env.dart';
   await File(filename).writeAsString('final environment = ${json.encode(config)};');
 }
\ No newline at end of file