v0.2.1, fixed InAppBrowser.injectScriptCode() method when there is not a return value, added InAppBrowser.onConsoleMessage() method to manage console messages #5

.idea/libraries/Flutter_Plugins.xml

@@ -1,5 +1,5 @@
 <component name="libraryTable">
-  <library name="Flutter Plugins" type="FlutterPluginsLibraryType">
+  <library name="Flutter Plugins">
     <CLASSES>
       <root url="file://$PROJECT_DIR$" />
     </CLASSES>

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.2.1
+
+- added InAppBrowser.onConsoleMessage() method to manage console messages
+- fixed InAppBrowser.injectScriptCode() method when there is not a return value
+
 ## 0.2.0
 
 - added support of Chrome CustomTabs for Android

README.md

@@ -41,6 +41,11 @@ class MyInAppBrowser extends InAppBrowser {
     print("\n\nStopped $url\n\n");
     // print body html
     print(await this.injectScriptCode("document.body.innerHTML"));
+
+    // console messages
+    await this.injectScriptCode("console.log({'testObject': 5});"); // the message will be: [object Object]
+    await this.injectScriptCode("console.log('testObjectStringify', JSON.stringify({'testObject': 5}));"); // the message will be: testObjectStringify {"testObject": 5}
+    await this.injectScriptCode("console.error('testError', false);"); // the message will be: testError false
     
     // add jquery library and custom javascript
     await this.injectScriptFile("https://code.jquery.com/jquery-3.3.1.min.js");
@@ -73,6 +78,17 @@ class MyInAppBrowser extends InAppBrowser {
     this.loadUrl(url);
   }
 
+  @override
+  void onConsoleMessage(ConsoleMessage consoleMessage) {
+    print("""
+    console output:
+      sourceURL: ${consoleMessage.sourceURL}
+      lineNumber: ${consoleMessage.lineNumber}
+      message: ${consoleMessage.message}
+      messageLevel: ${consoleMessage.messageLevel}
+    """);
+  }
+
 }
 
 MyInAppBrowser inAppBrowser = new MyInAppBrowser();
@@ -228,6 +244,14 @@ Event fires when the `InAppBrowser` window is closed.
   }
 ```
 
+Event fires when the `InAppBrowser` webview receives a `ConsoleMessage`.
+```dart
+  @override
+  void onConsoleMessage(ConsoleMessage consoleMessage) {
+
+  }
+```
+
 Give the host application a chance to take control when a URL is about to be loaded in the current WebView.
 In order to be able to listen this event, you need to set `useShouldOverrideUrlLoading` option to `true`.
 ```dart

android/.idea/.name

@@ -0,0 +1 @@
+flutter_inappbrowser

android/.idea/codeStyles/Project.xml

@@ -0,0 +1,29 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <Objective-C-extensions>
+      <file>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Import" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Macro" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Typedef" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Enum" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Constant" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Global" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Struct" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="FunctionPredecl" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Function" />
+      </file>
+      <class>
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Property" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="Synthesize" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InitMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="StaticMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="InstanceMethod" />
+        <option name="com.jetbrains.cidr.lang.util.OCDeclarationKind" value="DeallocMethod" />
+      </class>
+      <extensions>
+        <pair source="cpp" header="h" fileNamingConvention="NONE" />
+        <pair source="c" header="h" fileNamingConvention="NONE" />
+      </extensions>
+    </Objective-C-extensions>
+  </code_scheme>
+</component>

android/.idea/gradle.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="distributionType" value="DEFAULT_WRAPPED" />
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+          </set>
+        </option>
+        <option name="resolveModulePerSourceSet" value="false" />
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>

android/.idea/misc.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="NullableNotNullManager">
+    <option name="myDefaultNullable" value="android.support.annotation.Nullable" />
+    <option name="myDefaultNotNull" value="android.support.annotation.NonNull" />
+    <option name="myNullables">
+      <value>
+        <list size="7">
+          <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.Nullable" />
+          <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nullable" />
+          <item index="2" class="java.lang.String" itemvalue="javax.annotation.CheckForNull" />
+          <item index="3" class="java.lang.String" itemvalue="edu.umd.cs.findbugs.annotations.Nullable" />
+          <item index="4" class="java.lang.String" itemvalue="android.support.annotation.Nullable" />
+          <item index="5" class="java.lang.String" itemvalue="androidx.annotation.Nullable" />
+          <item index="6" class="java.lang.String" itemvalue="androidx.annotation.RecentlyNullable" />
+        </list>
+      </value>
+    </option>
+    <option name="myNotNulls">
+      <value>
+        <list size="6">
+          <item index="0" class="java.lang.String" itemvalue="org.jetbrains.annotations.NotNull" />
+          <item index="1" class="java.lang.String" itemvalue="javax.annotation.Nonnull" />
+          <item index="2" class="java.lang.String" itemvalue="edu.umd.cs.findbugs.annotations.NonNull" />
+          <item index="3" class="java.lang.String" itemvalue="android.support.annotation.NonNull" />
+          <item index="4" class="java.lang.String" itemvalue="androidx.annotation.NonNull" />
+          <item index="5" class="java.lang.String" itemvalue="androidx.annotation.RecentlyNonNull" />
+        </list>
+      </value>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/build/classes" />
+  </component>
+  <component name="ProjectType">
+    <option name="id" value="Android" />
+  </component>
+</project>

android/.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/flutter_inappbrowser.iml" filepath="$PROJECT_DIR$/flutter_inappbrowser.iml" />
+    </modules>
+  </component>
+</project>

android/.idea/runConfigurations.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RunConfigurationProducerService">
+    <option name="ignoredProducers">
+      <set>
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
+        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
+      </set>
+    </option>
+  </component>
+</project>

android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/InAppBrowserFlutterPlugin.java

@@ -285,15 +285,20 @@ public class InAppBrowserFlutterPlugin implements MethodCallHandler {
 
                 try {
                   String msg;
-                  msg = reader.nextString();
+                  if (reader.peek() == JsonToken.STRING) {
+                    msg = reader.nextString();
 
-                  JsonReader reader2 = new JsonReader(new StringReader(msg));
+                    JsonReader reader2 = new JsonReader(new StringReader(msg));
-                  reader2.setLenient(true);
+                    reader2.setLenient(true);
 
-                  if (reader2.peek() == JsonToken.STRING)
+                    if (reader2.peek() == JsonToken.STRING)
-                    msg = reader2.nextString();
+                      msg = reader2.nextString();
 
-                  result.success(msg);
+                    result.success(msg);
+                  }
+                  else {
+                    result.success("");
+                  }
 
                 } catch (IOException e) {
                   Log.e(LOG_TAG, "IOException", e);

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/InAppBrowserWebChromeClient.java

@@ -4,11 +4,16 @@ import android.content.Intent;
 import android.graphics.Bitmap;
 import android.net.Uri;
 import android.os.Build;
+import android.util.Log;
 import android.view.View;
+import android.webkit.ConsoleMessage;
 import android.webkit.ValueCallback;
 import android.webkit.WebChromeClient;
 import android.webkit.WebView;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class InAppBrowserWebChromeClient extends WebChromeClient {
 
     protected static final String LOG_TAG = "IABWebChromeClient";
@@ -22,6 +27,18 @@ public class InAppBrowserWebChromeClient extends WebChromeClient {
         this.activity = activity;
     }
 
+    @Override
+    public boolean onConsoleMessage(ConsoleMessage consoleMessage) {
+        Map<String, Object> obj = new HashMap<>();
+        obj.put("uuid", activity.uuid);
+        obj.put("sourceURL", consoleMessage.sourceId());
+        obj.put("lineNumber", consoleMessage.lineNumber());
+        obj.put("message", consoleMessage.message());
+        obj.put("messageLevel", consoleMessage.messageLevel().toString());
+        InAppBrowserFlutterPlugin.channel.invokeMethod("onConsoleMessage", obj);
+        return true;
+    }
+
     @Override
     public void onProgressChanged(WebView view, int progress) {
         if (activity.progressBar != null) {

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/InAppBrowserWebViewClient.java

@@ -4,6 +4,7 @@ import android.content.Intent;
 import android.graphics.Bitmap;
 import android.net.Uri;
 import android.net.http.SslError;
+import android.os.Build;
 import android.util.Log;
 import android.webkit.CookieManager;
 import android.webkit.CookieSyncManager;
@@ -124,7 +125,7 @@ public class InAppBrowserWebViewClient extends WebViewClient {
         activity.isLoading = false;
 
         // CB-10395 InAppBrowserFlutterPlugin's WebView not storing cookies reliable to local device storage
-        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
             CookieManager.getInstance().flush();
         } else {
             CookieSyncManager.getInstance().sync();
@@ -134,6 +135,10 @@ public class InAppBrowserWebViewClient extends WebViewClient {
         view.clearFocus();
         view.requestFocus();
 
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
+            view.evaluateJavascript(activity.jsConsoleLogScript, null);
+        }
+
         Map<String, Object> obj = new HashMap<>();
         obj.put("uuid", activity.uuid);
         obj.put("url", url);

android/src/main/java/com/pichillilorenzo/flutter_inappbrowser/WebViewActivity.java

@@ -38,6 +38,32 @@ public class WebViewActivity extends AppCompatActivity {
     public boolean isLoading = false;
     public boolean isHidden = false;
 
+    static final String jsConsoleLogScript = "(function() {\n"+
+"   var oldLogs = {\n"+
+"       'log': console.log,\n"+
+"       'debug': console.debug,\n"+
+"       'error': console.error,\n"+
+"       'info': console.info,\n"+
+"       'warn': console.warn\n"+
+"   };\n"+
+"   for (var k in oldLogs) {\n"+
+"       (function(oldLog) {\n"+
+"           console[oldLog] = function() {\n"+
+"               var message = ''\n"+
+"               for (var i in arguments) {\n"+
+"                   if (message == '') {\n"+
+"                       message += arguments[i];\n"+
+"                   }\n"+
+"                   else {\n"+
+"                       message += ' ' + arguments[i];\n"+
+"                   }\n"+
+"               }\n"+
+"               oldLogs[oldLog].call(console, message);\n"+
+"           }\n"+
+"       })(k);\n"+
+"   }\n"+
+"})();";
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

example/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.2.0'
     }
 }
 

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Fri Jun 23 08:50:38 CEST 2017
+#Fri Oct 05 14:08:48 CEST 2018
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip

example/lib/main.dart

@@ -12,7 +12,19 @@ class MyInAppBrowser extends InAppBrowser {
   @override
   Future onLoadStop(String url) async {
     print("\n\nStopped $url\n\n");
+
+//    // javascript error
+//    await this.injectScriptCode("console.log({'testJavaScriptError': 5}));");
+//
+//    await this.injectScriptCode("console.log({'testObject': 5});");
+//    await this.injectScriptCode("console.warn('testWarn',null);");
+//    await this.injectScriptCode("console.log('testObjectStringify', JSON.stringify({'asd': 5}));");
+//    await this.injectScriptCode("console.info('testInfo', 6);");
+//    await this.injectScriptCode("console.error('testError', false);");
+//    await this.injectScriptCode("console.debug('testDebug', true);");
 //    print(await this.injectScriptCode("document.body.innerHTML"));
+//    print(await this.injectScriptCode("null"));
+//    print(await this.injectScriptCode("undefined"));
 //    print(await this.injectScriptCode("3"));
 //    print(await this.injectScriptCode("""
 //      function asd (a,b) {
@@ -58,6 +70,17 @@ class MyInAppBrowser extends InAppBrowser {
     print("\n\n override $url\n\n");
     this.loadUrl(url);
   }
+
+  @override
+  void onConsoleMessage(ConsoleMessage consoleMessage) {
+    print("""
+    console output: 
+      sourceURL: ${consoleMessage.sourceURL}
+      lineNumber: ${consoleMessage.lineNumber}
+      message: ${consoleMessage.message}
+      messageLevel: ${consoleMessage.messageLevel}
+    """);
+  }
 }
 
 MyInAppBrowser inAppBrowserFallback = new MyInAppBrowser();
@@ -107,15 +130,15 @@ class _MyAppState extends State<MyApp> {
         ),
         body: new Center(
           child: new RaisedButton(onPressed: () {
-            chromeSafariBrowser.open("https://flutter.io/");
+            //chromeSafariBrowser.open("https://flutter.io/");
-//              inAppBrowserFallback.open("https://flutter.io/", options: {
+            inAppBrowserFallback.open("https://flutter.io/", options: {
-//                //"hidden": true,
+              //"hidden": true,
-//                //"toolbarTopFixedTitle": "Fixed title",
+              //"toolbarTopFixedTitle": "Fixed title",
-//                //"useShouldOverrideUrlLoading": true
+              //"useShouldOverrideUrlLoading": true
-//                //"hideUrlBar": true,
+              //"hideUrlBar": true,
-//                //"toolbarTop": false,
+              //"toolbarTop": false,
-//                //"toolbarBottom": false
+              //"toolbarBottom": false
-//              });
+            });
 
           },
           child: Text("Open InAppBrowser")

ios/Classes/InAppBrowserWebViewController.swift

@@ -14,6 +14,36 @@ import AVFoundation
 typealias OlderClosureType =  @convention(c) (Any, Selector, UnsafeRawPointer, Bool, Bool, Any?) -> Void
 typealias NewerClosureType =  @convention(c) (Any, Selector, UnsafeRawPointer, Bool, Bool, Bool, Any?) -> Void
 
+// the message needs to be concatenated with '' in order to have the same behavior like on Android
+let jsConsoleLog = """
+(function() {
+    var oldLogs = {
+        'consoleLog': console.log,
+        'consoleDebug': console.debug,
+        'consoleError': console.error,
+        'consoleInfo': console.info,
+        'consoleWarn': console.warn
+    };
+
+    for (var k in oldLogs) {
+        (function(oldLog) {
+            console[oldLog.replace('console', '').toLowerCase()] = function() {
+                var message = '';
+                for (var i in arguments) {
+                    if (message == '') {
+                        message += arguments[i];
+                    }
+                    else {
+                        message += ' ' + arguments[i];
+                    }
+                }
+                window.webkit.messageHandlers[oldLog].postMessage(message);
+            }
+        })(k);
+    }
+})();
+"""
+
 extension WKWebView{
     
     var keyboardDisplayRequiresUserAction: Bool? {
@@ -62,7 +92,7 @@ extension WKWebView{
     
 }
 
-class InAppBrowserWebViewController: UIViewController, WKUIDelegate, WKNavigationDelegate, UITextFieldDelegate {
+class InAppBrowserWebViewController: UIViewController, WKUIDelegate, WKNavigationDelegate, UITextFieldDelegate, WKScriptMessageHandler {
     @IBOutlet var webView: WKWebView!
     @IBOutlet var closeButton: UIButton!
     @IBOutlet var reloadButton: UIBarButtonItem!
@@ -132,7 +162,6 @@ class InAppBrowserWebViewController: UIViewController, WKUIDelegate, WKNavigatio
     }
     
     func prepareWebView() {
-        
         //UIApplication.shared.statusBarStyle = preferredStatusBarStyle
         
         self.webView.configuration.userContentController = WKUserContentController()
@@ -208,6 +237,13 @@ class InAppBrowserWebViewController: UIViewController, WKUIDelegate, WKNavigatio
         let jscriptWebkitTouchCallout = WKUserScript(source: "document.body.style.webkitTouchCallout='none';", injectionTime: .atDocumentEnd, forMainFrameOnly: true)
         self.webView.configuration.userContentController.addUserScript(jscriptWebkitTouchCallout)
         
+        let jsConsoleLogScript = WKUserScript(source: jsConsoleLog, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
+        self.webView.configuration.userContentController.addUserScript(jsConsoleLogScript)
+        self.webView.configuration.userContentController.add(self, name: "consoleLog")
+        self.webView.configuration.userContentController.add(self, name: "consoleDebug")
+        self.webView.configuration.userContentController.add(self, name: "consoleError")
+        self.webView.configuration.userContentController.add(self, name: "consoleInfo")
+        self.webView.configuration.userContentController.add(self, name: "consoleWarn")
         
         if #available(iOS 10.0, *) {
             if (browserOptions?.mediaPlaybackRequiresUserGesture)! {
@@ -481,6 +517,10 @@ class InAppBrowserWebViewController: UIViewController, WKUIDelegate, WKNavigatio
     
     func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
         // update url, stop spinner, update back/forward
+        
+        // evaluate the console log script
+        webView.evaluateJavaScript(jsConsoleLog)
+        
         currentURL = webView.url
         updateUrlTextField(url: (currentURL?.absoluteString)!)
         backButton.isEnabled = webView.canGoBack
@@ -506,4 +546,34 @@ class InAppBrowserWebViewController: UIViewController, WKUIDelegate, WKNavigatio
         spinner.stopAnimating()
         navigationDelegate?.onLoadError(uuid: self.uuid, webView: webView, error: error)
     }
+    
+    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+        print(message.name)
+        if message.name.starts(with: "console") {
+            var messageLevel = "LOG"
+            switch (message.name) {
+                case "consoleLog":
+                    messageLevel = "LOG"
+                    break;
+                case "consoleDebug":
+                    // on Android, console.debug is TIP
+                    messageLevel = "TIP"
+                    break;
+                case "consoleError":
+                    messageLevel = "ERROR"
+                    break;
+                case "consoleInfo":
+                    // on Android, console.info is LOG
+                    messageLevel = "LOG"
+                    break;
+                case "consoleWarn":
+                    messageLevel = "WARNING"
+                    break;
+                default:
+                    messageLevel = "LOG"
+                    break;
+            }
+            navigationDelegate?.onConsoleMessage(uuid: self.uuid, sourceURL: "", lineNumber: 1, message: message.body as! String, messageLevel: messageLevel)
+        }
+    }
 }

ios/Classes/SwiftFlutterPlugin.swift

@@ -48,98 +48,98 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
         let uuid: String = (arguments!["uuid"] as? String)!
         
         switch call.method {
-        case "open":
+            case "open":
-            self.open(uuid: uuid, arguments: arguments!, result: result)
+                self.open(uuid: uuid, arguments: arguments!, result: result)
-            break
+                break
-        case "loadUrl":
+            case "loadUrl":
-            self.loadUrl(uuid: uuid, arguments: arguments!, result: result)
+                self.loadUrl(uuid: uuid, arguments: arguments!, result: result)
-            break
+                break
-        case "close":
+            case "close":
-            self.close(uuid: uuid)
+                self.close(uuid: uuid)
-            result(true)
+                result(true)
-            break
+                break
-        case "show":
+            case "show":
-            self.show(uuid: uuid)
+                self.show(uuid: uuid)
-            result(true)
+                result(true)
-            break
+                break
-        case "hide":
+            case "hide":
-            self.hide(uuid: uuid)
+                self.hide(uuid: uuid)
-            result(true)
+                result(true)
-            break
+                break
-        case "reload":
+            case "reload":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                webViewController?.reload()
+                    webViewController?.reload()
-            }
+                }
-            result(true)
+                result(true)
-            break
+                break
-        case "goBack":
+            case "goBack":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                webViewController?.goBack()
+                    webViewController?.goBack()
-            }
+                }
-            result(true)
+                result(true)
-            break
+                break
-        case "canGoBack":
+            case "canGoBack":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                result(webViewController?.canGoBack() ?? false)
+                    result(webViewController?.canGoBack() ?? false)
-            }
+                }
-            else {
+                else {
-                result(false)
+                    result(false)
-            }
+                }
-            break
+                break
-        case "goForward":
+            case "goForward":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                webViewController?.goForward()
+                    webViewController?.goForward()
-            }
+                }
-            result(true)
+                result(true)
-            break
+                break
-        case "canGoForward":
+            case "canGoForward":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                result(webViewController?.canGoForward() ?? false)
+                    result(webViewController?.canGoForward() ?? false)
-            }
+                }
-            else {
+                else {
-                result(false)
+                    result(false)
-            }
+                }
-            break
+                break
-        case "isLoading":
+            case "isLoading":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                result((webViewController?.webView.isLoading ?? false) == true)
+                    result((webViewController?.webView.isLoading ?? false) == true)
-            }
+                }
-            else {
+                else {
-                result(false)
+                    result(false)
-            }
+                }
-            break
+                break
-        case "stopLoading":
+            case "stopLoading":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                webViewController?.webView.stopLoading()
+                    webViewController?.webView.stopLoading()
-            }
+                }
-            result(true)
+                result(true)
-            break
+                break
-        case "isHidden":
+            case "isHidden":
-            if let webViewController = self.webViewControllers[uuid] {
+                if let webViewController = self.webViewControllers[uuid] {
-                result((webViewController?.isHidden ?? false) == true)
+                    result((webViewController?.isHidden ?? false) == true)
-            }
+                }
-            else {
+                else {
-                result(false)
+                    result(false)
-            }
+                }
-            break
+                break
-        case "injectScriptCode":
+            case "injectScriptCode":
-            self.injectScriptCode(uuid: uuid, arguments: arguments!, result: result)
+                self.injectScriptCode(uuid: uuid, arguments: arguments!, result: result)
-            break
+                break
-        case "injectScriptFile":
+            case "injectScriptFile":
-            self.injectScriptFile(uuid: uuid, arguments: arguments!, result: nil)
+                self.injectScriptFile(uuid: uuid, arguments: arguments!, result: nil)
-            result(true)
+                result(true)
-            break
+                break
-        case "injectStyleCode":
+            case "injectStyleCode":
-            self.injectStyleCode(uuid: uuid, arguments: arguments!, result: nil)
+                self.injectStyleCode(uuid: uuid, arguments: arguments!, result: nil)
-            result(true)
+                result(true)
-            break
+                break
-        case "injectStyleFile":
+            case "injectStyleFile":
-            self.injectStyleFile(uuid: uuid, arguments: arguments!, result: nil)
+                self.injectStyleFile(uuid: uuid, arguments: arguments!, result: nil)
-            result(true)
+                result(true)
-            break
+                break
-        default:
+            default:
-            result(FlutterMethodNotImplemented)
+                result(FlutterMethodNotImplemented)
-            break
+                break
         }
     }
     
@@ -410,6 +410,16 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
                         return
                     }
                     
+                    if error != nil {
+                        let userInfo = (error! as NSError).userInfo
+                        self.onConsoleMessage(uuid: uuid, sourceURL: (userInfo["WKJavaScriptExceptionSourceURL"] as! URL).absoluteString, lineNumber: userInfo["WKJavaScriptExceptionLineNumber"] as! Int, message: userInfo["WKJavaScriptExceptionMessage"] as! String, messageLevel: "ERROR")
+                    }
+                    
+                    if value == nil {
+                        result!("")
+                        return
+                    }
+                    
                     do {
                         let data: Data = ("[" + String(describing: value!) + "]").data(using: String.Encoding.utf8, allowLossyConversion: false)!
                         let json: Array<Any> = try JSONSerialization.jsonObject(with: data, options: []) as! Array<Any>
@@ -476,19 +486,25 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
     }
     
     func shouldOverrideUrlLoading(uuid: String, webView: WKWebView, url: URL) {
-        if let webViewController = self.webViewControllers[uuid] {
+        if self.webViewControllers[uuid] != nil {
             channel.invokeMethod("shouldOverrideUrlLoading", arguments: ["uuid": uuid, "url": url.absoluteString])
         }
     }
     
+    func onConsoleMessage(uuid: String, sourceURL: String, lineNumber: Int, message: String, messageLevel: String) {
+        if self.webViewControllers[uuid] != nil {
+            channel.invokeMethod("onConsoleMessage", arguments: ["uuid": uuid, "sourceURL": sourceURL, "lineNumber": lineNumber, "message": message, "messageLevel": messageLevel])
+        }
+    }
+    
     func onChromeSafariBrowserOpened(uuid: String) {
-        if let safariViewController = self.safariViewControllers[uuid] {
+        if self.safariViewControllers[uuid] != nil {
             channel.invokeMethod("onChromeSafariBrowserOpened", arguments: ["uuid": uuid])
         }
     }
     
     func onChromeSafariBrowserLoaded(uuid: String) {
-        if let safariViewController = self.safariViewControllers[uuid] {
+        if self.safariViewControllers[uuid] != nil {
             channel.invokeMethod("onChromeSafariBrowserLoaded", arguments: ["uuid": uuid])
         }
     }

lib/flutter_inappbrowser.dart

@@ -27,7 +27,26 @@ import 'package:uuid/uuid.dart';
 
 typedef Future<dynamic> ListenerCallback(MethodCall call);
 
-var uuidGenerator = new Uuid();
+var _uuidGenerator = new Uuid();
+
+///
+enum ConsoleMessageLevel {
+  DEBUG, ERROR, LOG, TIP, WARNING
+}
+
+///Public class representing a JavaScript console message from WebCore.
+///This could be a issued by a call to one of the console logging functions (e.g. console.log('...')) or a JavaScript error on the page.
+///
+///To receive notifications of these messages, override the [InAppBrowser.onConsoleMessage()] function.
+class ConsoleMessage {
+
+  String sourceURL = "";
+  int lineNumber = 1;
+  String message = "";
+  ConsoleMessageLevel messageLevel = ConsoleMessageLevel.LOG;
+
+  ConsoleMessage(this.sourceURL, this.lineNumber, this.message, this.messageLevel);
+}
 
 class _ChannelManager {
   static const MethodChannel channel = const MethodChannel('com.pichillilorenzo/flutter_inappbrowser');
@@ -53,14 +72,14 @@ class _ChannelManager {
 
 ///InAppBrowser class.
 ///
-/// This class uses the native WebView of the platform.
+///This class uses the native WebView of the platform.
 class InAppBrowser {
 
   String uuid;
 
   ///
   InAppBrowser () {
-    uuid = uuidGenerator.v4();
+    uuid = _uuidGenerator.v4();
     _ChannelManager.addListener(uuid, _handleMethod);
   }
 
@@ -87,6 +106,19 @@ class InAppBrowser {
         String url = call.arguments["url"];
         shouldOverrideUrlLoading(url);
         break;
+      case "onConsoleMessage":
+        String sourceURL = call.arguments["sourceURL"];
+        int lineNumber = call.arguments["lineNumber"];
+        String message = call.arguments["message"];
+        ConsoleMessageLevel messageLevel;
+        ConsoleMessageLevel.values.forEach((element) {
+          if ("ConsoleMessageLevel." + call.arguments["messageLevel"] == element.toString()) {
+            messageLevel = element;
+            return;
+          }
+        });
+        onConsoleMessage(ConsoleMessage(sourceURL, lineNumber, message, messageLevel));
+        break;
     }
     return new Future.value("");
   }
@@ -291,6 +323,11 @@ class InAppBrowser {
 
   }
 
+  ///Event fires when the [InAppBrowser] webview receives a [ConsoleMessage].
+  void onConsoleMessage(ConsoleMessage consoleMessage) {
+
+  }
+
 }
 
 ///ChromeSafariBrowser class.
@@ -305,7 +342,7 @@ class ChromeSafariBrowser {
 
   ///Initialize the [ChromeSafariBrowser] instance with a [InAppBrowser] fallback instance or `null`.
   ChromeSafariBrowser (bf) {
-    uuid = uuidGenerator.v4();
+    uuid = _uuidGenerator.v4();
     browserFallback = bf;
     _ChannelManager.addListener(uuid, _handleMethod);
   }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_inappbrowser
 description: A Flutter plugin that allows you to open an in-app browser window. (inspired by the popular cordova-plugin-inappbrowser).
-version: 0.2.0
+version: 0.2.1
 author: Lorenzo Pichilli <pichillilorenzo@gmail.com>
 homepage: https://github.com/pichillilorenzo/flutter_inappbrowser