Added InAppWebView.headlessWebView property to convert an HeadlessWebView to InAppWebView widget

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 6.0.0-beta.4
+
+- Added `InAppWebView.headlessWebView` property to convert an `HeadlessWebView` to `InAppWebView` widget
+
 ## 6.0.0-beta.3
 
 - Added MacOS support
@@ -46,6 +50,12 @@
 - Removed `URLProtectionSpace.iosIsProxy` property
 - `historyUrl` and `baseUrl` of `InAppWebViewInitialData` can be `null`
 
+## 5.5.0+4
+
+- Fixed "Many crashes on iOS: Completion handler was not called" [#1221](https://github.com/pichillilorenzo/flutter_inappwebview/issues/1221)
+- Fixed "webView:didReceiveAuthenticationChallenge:completionHandler" [#1128](https://github.com/pichillilorenzo/flutter_inappwebview/issues/1128)
+- Merged "Fix missing import for Flutter 2.8.1" [#1381](https://github.com/pichillilorenzo/flutter_inappwebview/pull/1381) (thanks to [chandrabezzo](https://github.com/chandrabezzo))
+
 ## 5.5.0+3
 
 - Fixed iOS `toolbarTopTintColor` InAppBrowser option

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/FlutterWebViewFactory.java

@@ -2,6 +2,8 @@ package com.pichillilorenzo.flutter_inappwebview;
 
 import android.content.Context;
 
+import com.pichillilorenzo.flutter_inappwebview.headless_in_app_webview.HeadlessInAppWebView;
+import com.pichillilorenzo.flutter_inappwebview.headless_in_app_webview.HeadlessInAppWebViewManager;
 import com.pichillilorenzo.flutter_inappwebview.webview.in_app_webview.FlutterWebView;
 import com.pichillilorenzo.flutter_inappwebview.webview.PlatformWebView;
 import com.pichillilorenzo.flutter_inappwebview.types.WebViewImplementation;
@@ -24,15 +26,25 @@ public class FlutterWebViewFactory extends PlatformViewFactory {
   @Override
   public PlatformView create(Context context, int id, Object args) {
     HashMap<String, Object> params = (HashMap<String, Object>) args;
+    PlatformWebView flutterWebView = null;
 
-    PlatformWebView flutterWebView;
+    String headlessWebViewId = (String) params.get("headlessWebViewId");
-    WebViewImplementation implementation = WebViewImplementation.fromValue((Integer) params.get("implementation"));
+    if (headlessWebViewId != null) {
-    switch (implementation) {
+      HeadlessInAppWebView headlessInAppWebView = HeadlessInAppWebViewManager.webViews.get(headlessWebViewId);
-      case NATIVE:
+      if (headlessInAppWebView != null) {
-      default:
+        flutterWebView = headlessInAppWebView.disposeAndGetFlutterWebView();
-        flutterWebView = new FlutterWebView(plugin, context, id, params);
+      }
+    }
+
+    if (flutterWebView == null) {
+      WebViewImplementation implementation = WebViewImplementation.fromValue((Integer) params.get("implementation"));
+      switch (implementation) {
+        case NATIVE:
+        default:
+          flutterWebView = new FlutterWebView(plugin, context, id, params);
+      }
+      flutterWebView.makeInitialLoad(params);
     }
-    flutterWebView.makeInitialLoad(params);
     
     return flutterWebView;
   }

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/Util.java

@@ -2,18 +2,25 @@ package com.pichillilorenzo.flutter_inappwebview;
 
 import android.content.Context;
 import android.content.res.AssetManager;
+import android.graphics.Insets;
+import android.graphics.Rect;
 import android.net.http.SslCertificate;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
 import android.text.TextUtils;
+import android.util.DisplayMetrics;
 import android.util.Log;
+import android.view.WindowInsets;
+import android.view.WindowManager;
+import android.view.WindowMetrics;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 
+import com.pichillilorenzo.flutter_inappwebview.types.Size2D;
 import com.pichillilorenzo.flutter_inappwebview.types.SyncBaseCallbackResultImpl;
 
 import org.json.JSONArray;
@@ -242,6 +249,31 @@ public class Util {
     return context.getResources().getDisplayMetrics().density;
   }
 
+  public static Size2D getFullscreenSize(Context context) {
+    Size2D fullscreenSize = new Size2D(-1, -1);
+    WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
+    if (wm != null) {
+      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+        final WindowMetrics metrics = wm.getCurrentWindowMetrics();
+        // Gets all excluding insets
+        final WindowInsets windowInsets = metrics.getWindowInsets();
+        Insets insets = windowInsets.getInsetsIgnoringVisibility(WindowInsets.Type.navigationBars()
+                | WindowInsets.Type.displayCutout());
+        int insetsWidth = insets.right + insets.left;
+        int insetsHeight = insets.top + insets.bottom;
+        final Rect bounds = metrics.getBounds();
+        fullscreenSize.setWidth(bounds.width() - insetsWidth);
+        fullscreenSize.setHeight(bounds.height() - insetsHeight);
+      } else {
+        DisplayMetrics displayMetrics = new DisplayMetrics();
+        wm.getDefaultDisplay().getMetrics(displayMetrics);
+        fullscreenSize.setWidth(displayMetrics.widthPixels);
+        fullscreenSize.setHeight(displayMetrics.heightPixels);
+      }
+    }
+    return fullscreenSize;
+  }
+
   public static boolean isClass(String className) {
     try  {
       Class.forName(className);

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/headless_in_app_webview/HeadlessInAppWebView.java

@@ -9,13 +9,12 @@ import androidx.annotation.Nullable;
 
 import com.pichillilorenzo.flutter_inappwebview.InAppWebViewFlutterPlugin;
 import com.pichillilorenzo.flutter_inappwebview.Util;
-import com.pichillilorenzo.flutter_inappwebview.webview.in_app_webview.FlutterWebView;
 import com.pichillilorenzo.flutter_inappwebview.types.Disposable;
 import com.pichillilorenzo.flutter_inappwebview.types.Size2D;
+import com.pichillilorenzo.flutter_inappwebview.webview.in_app_webview.FlutterWebView;
 
 import java.util.Map;
 
-import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
 
 public class HeadlessInAppWebView implements Disposable {
@@ -54,15 +53,16 @@ public class HeadlessInAppWebView implements Disposable {
         ViewGroup mainView = (ViewGroup) (contentView).getChildAt(0);
         if (mainView != null && flutterWebView != null) {
           View view = flutterWebView.getView();
-          final Map<String, Object> initialSize = (Map<String, Object>) params.get("initialSize");
+          if (view != null) {
-          Size2D size = Size2D.fromMap(initialSize);
+            final Map<String, Object> initialSize = (Map<String, Object>) params.get("initialSize");
-          if (size != null) {
+            Size2D size = Size2D.fromMap(initialSize);
+            if (size == null) {
+              size = new Size2D(-1, -1);
+            }
             setSize(size);
-          } else {
+            mainView.addView(view, 0);
-            view.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
+            view.setVisibility(View.INVISIBLE);
           }
-          mainView.addView(view, 0);
-          view.setVisibility(View.INVISIBLE);
         } 
       }
     }
@@ -71,8 +71,13 @@ public class HeadlessInAppWebView implements Disposable {
   public void setSize(@NonNull Size2D size) {
     if (flutterWebView != null && flutterWebView.webView != null) {
       View view = flutterWebView.getView();
-      float scale = Util.getPixelDensity(view.getContext());
+      if (view != null) {
-      view.setLayoutParams(new FrameLayout.LayoutParams((int) (size.getWidth() * scale), (int) (size.getHeight() * scale)));
+        float scale = Util.getPixelDensity(view.getContext());
+        Size2D fullscreenSize = Util.getFullscreenSize(view.getContext());
+        int width = (int) (size.getWidth() == -1 ? fullscreenSize.getWidth() : (size.getWidth() * scale));
+        int height = (int) (size.getWidth() == -1 ? fullscreenSize.getHeight() : (size.getHeight() * scale));
+        view.setLayoutParams(new FrameLayout.LayoutParams(width, height));
+      }
     }
   }
 
@@ -80,13 +85,41 @@ public class HeadlessInAppWebView implements Disposable {
   public Size2D getSize() {
     if (flutterWebView != null && flutterWebView.webView != null) {
       View view = flutterWebView.getView();
-      float scale = Util.getPixelDensity(view.getContext());
+      if (view != null) {
-      ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
+        float scale = Util.getPixelDensity(view.getContext());
-      return new Size2D(layoutParams.width / scale, layoutParams.height / scale);
+        Size2D fullscreenSize = Util.getFullscreenSize(view.getContext());
+        ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
+        return new Size2D(
+                fullscreenSize.getWidth() == layoutParams.width ? layoutParams.width : (layoutParams.width / scale),
+                fullscreenSize.getHeight() == layoutParams.height ? layoutParams.height : (layoutParams.height / scale)
+        );
+      }
     }
     return null;
   }
 
+  @Nullable
+  public FlutterWebView disposeAndGetFlutterWebView() {
+    FlutterWebView newFlutterWebView = flutterWebView;
+    if (flutterWebView != null) {
+      View view = flutterWebView.getView();
+      if (view != null) {
+        // restore WebView layout params and visibility
+        view.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
+        view.setVisibility(View.VISIBLE);
+        // remove from parent
+        ViewGroup parent = (ViewGroup) view.getParent();
+        if (parent != null) {
+          parent.removeView(view);
+        }
+      }
+      // set to null to avoid to be disposed before calling "dispose()"
+      flutterWebView = null;
+      dispose();
+    }
+    return newFlutterWebView;
+  }
+
   public void dispose() {
     if (channelDelegate != null) {
       channelDelegate.dispose();
@@ -100,7 +133,10 @@ public class HeadlessInAppWebView implements Disposable {
       if (contentView != null) {
         ViewGroup mainView = (ViewGroup) (contentView).getChildAt(0);
         if (mainView != null && flutterWebView != null) {
-          mainView.removeView(flutterWebView.getView());
+          View view = flutterWebView.getView();
+          if (view != null) {
+            mainView.removeView(flutterWebView.getView());
+          }
         }
       }
     }

example/integration_test/headless_in_app_webview/convert_to_inappwebview.dart

@@ -0,0 +1,74 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../constants.dart';
+
+void convertToInAppWebView() {
+  final shouldSkip = kIsWeb
+      ? false
+      : ![
+          TargetPlatform.android,
+          TargetPlatform.iOS,
+        ].contains(defaultTargetPlatform);
+
+  testWidgets('convert to InAppWebView', (WidgetTester tester) async {
+    final Completer<InAppWebViewController> controllerCompleter =
+        Completer<InAppWebViewController>();
+    final Completer<void> pageLoaded = Completer<void>();
+
+    var headlessWebView = new HeadlessInAppWebView(
+      initialUrlRequest: URLRequest(url: TEST_CROSS_PLATFORM_URL_1),
+      onWebViewCreated: (controller) {
+        controllerCompleter.complete(controller);
+      },
+    );
+    headlessWebView.onLoadStop = (controller, url) async {
+      pageLoaded.complete();
+    };
+
+    await headlessWebView.run();
+    expect(headlessWebView.isRunning(), true);
+
+    final InAppWebViewController controller = await controllerCompleter.future;
+    await pageLoaded.future;
+
+    final String? url = (await controller.getUrl())?.toString();
+    expect(url, TEST_CROSS_PLATFORM_URL_1.toString());
+
+    final Completer<InAppWebViewController> widgetControllerCompleter =
+    Completer<InAppWebViewController>();
+    final Completer<String> loadedUrl = Completer<String>();
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: InAppWebView(
+          key: GlobalKey(),
+          headlessWebView: headlessWebView,
+          onWebViewCreated: (controller) {
+            widgetControllerCompleter.complete(controller);
+          },
+          onLoadStop: (controller, url) {
+            if (url.toString() == TEST_CROSS_PLATFORM_URL_2.toString() &&
+                !loadedUrl.isCompleted) {
+              loadedUrl.complete(url.toString());
+            }
+          },
+        ),
+      ),
+    );
+    final InAppWebViewController widgetController = await widgetControllerCompleter.future;
+
+    expect(headlessWebView.isRunning(), false);
+
+    expect((await widgetController.getUrl())?.toString(), TEST_CROSS_PLATFORM_URL_1.toString());
+
+    await widgetController.loadUrl(
+        urlRequest: URLRequest(url: TEST_CROSS_PLATFORM_URL_2));
+    expect(await loadedUrl.future, TEST_CROSS_PLATFORM_URL_2.toString());
+  }, skip: shouldSkip);
+}

example/integration_test/headless_in_app_webview/main.dart

@@ -1,5 +1,6 @@
 import 'package:flutter_test/flutter_test.dart';
 
+import 'convert_to_inappwebview.dart';
 import 'take_screenshot.dart';
 import 'custom_size.dart';
 import 'run_and_dispose.dart';
@@ -11,5 +12,6 @@ void main() {
     takeScreenshot();
     customSize();
     setGetSettings();
+    convertToInAppWebView();
   });
 }

example/integration_test/headless_in_app_webview/take_screenshot.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
@@ -26,7 +27,9 @@ void takeScreenshot() {
           controllerCompleter.complete(controller);
         },
         onLoadStop: (controller, url) async {
-          pageLoaded.complete();
+          if (!pageLoaded.isCompleted) {
+            pageLoaded.complete();
+          }
         });
 
     await headlessWebView.run();

example/integration_test/in_app_webview/audio_playback_policy.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';

example/integration_test/in_app_webview/load_url.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';

example/integration_test/in_app_webview/on_received_icon.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';

example/integration_test/in_app_webview/post_requests.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';

example/integration_test/in_app_webview/video_playback_policy.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';

example/ios/Flutter/flutter_export_environment.sh

@@ -3,12 +3,11 @@
 export "FLUTTER_ROOT=/Users/lorenzopichilli/fvm/versions/2.10.4"
 export "FLUTTER_APPLICATION_PATH=/Users/lorenzopichilli/Desktop/flutter_inappwebview/example"
 export "COCOAPODS_PARALLEL_CODE_SIGN=true"
-export "FLUTTER_TARGET=/Users/lorenzopichilli/Desktop/flutter_inappwebview/example/lib/main.dart"
+export "FLUTTER_TARGET=lib/main.dart"
 export "FLUTTER_BUILD_DIR=build"
 export "FLUTTER_BUILD_NAME=1.0.0"
 export "FLUTTER_BUILD_NUMBER=1"
-export "DART_DEFINES=Zmx1dHRlci5pbnNwZWN0b3Iuc3RydWN0dXJlZEVycm9ycz10cnVl,RkxVVFRFUl9XRUJfQVVUT19ERVRFQ1Q9dHJ1ZQ=="
 export "DART_OBFUSCATION=false"
 export "TRACK_WIDGET_CREATION=true"
 export "TREE_SHAKE_ICONS=false"
-export "PACKAGE_CONFIG=/Users/lorenzopichilli/Desktop/flutter_inappwebview/example/.dart_tool/package_config.json"
+export "PACKAGE_CONFIG=.dart_tool/package_config.json"

example/lib/generated_plugin_registrant.dart

@@ -0,0 +1,19 @@
+//
+// Generated file. Do not edit.
+//
+
+// ignore_for_file: directives_ordering
+// ignore_for_file: lines_longer_than_80_chars
+// ignore_for_file: depend_on_referenced_packages
+
+import 'package:flutter_inappwebview/flutter_inappwebview.dart';
+import 'package:url_launcher_web/url_launcher_web.dart';
+
+import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+
+// ignore: public_member_api_docs
+void registerPlugins(Registrar registrar) {
+  FlutterInAppWebViewWebPlatform.registerWith(registrar);
+  UrlLauncherPlugin.registerWith(registrar);
+  registrar.registerMessageHandler();
+}

example/lib/in_app_webiew_example.screen.dart

@@ -114,8 +114,9 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
               children: [
                 InAppWebView(
                   key: webViewKey,
+                  headlessWebView: headlessWebView,
                   initialUrlRequest:
-                      URLRequest(url: Uri.parse('https://flutter.dev')),
+                      URLRequest(url: Uri.parse('https://google.com')),
                   // initialUrlRequest:
                   // URLRequest(url: Uri.parse(Uri.base.toString().replaceFirst("/#/", "/") + 'page.html')),
                   // initialFile: "assets/index.html",
@@ -125,6 +126,7 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
                   pullToRefreshController: pullToRefreshController,
                   onWebViewCreated: (controller) async {
                     webViewController = controller;
+                    print(await controller.getUrl());
                   },
                   onLoadStart: (controller, url) async {
                     setState(() {

example/lib/main.dart

@@ -15,6 +15,13 @@ import 'package:pointer_interceptor/pointer_interceptor.dart';
 
 InAppLocalhostServer localhostServer = new InAppLocalhostServer(documentRoot: 'assets');
 
+var headlessWebView = new HeadlessInAppWebView(
+  initialUrlRequest: URLRequest(url: Uri.parse('https://flutter.dev')),
+  shouldOverrideUrlLoading: (controller, navigationAction) async {
+    return NavigationActionPolicy.ALLOW;
+  },
+);
+
 Future main() async {
   WidgetsFlutterBinding.ensureInitialized();
   // await Permission.camera.request();
@@ -29,6 +36,10 @@ Future main() async {
     await localhostServer.start();
   }
 
+  headlessWebView.run();
+
+  await Future.delayed(Duration(seconds: 1));
+
   runApp(MyApp());
 }
 

ios/Classes/HeadlessInAppWebView/HeadlessInAppWebView.swift

@@ -61,6 +61,19 @@ public class HeadlessInAppWebView : Disposable {
         return nil
     }
     
+    public func disposeAndGetFlutterWebView(withFrame frame: CGRect) -> FlutterWebViewController? {
+        let newFlutterWebView = flutterWebView
+        if let view = flutterWebView?.view() {
+            // restore WebView frame and alpha
+            view.frame = frame
+            view.alpha = 1.0
+            // remove from parent
+            view.removeFromSuperview()
+            dispose()
+        }
+        return newFlutterWebView
+    }
+    
     public func dispose() {
         channelDelegate?.dispose()
         channelDelegate = nil

ios/Classes/InAppWebView/FlutterWebViewFactory.swift

@@ -23,6 +23,13 @@ public class FlutterWebViewFactory: NSObject, FlutterPlatformViewFactory {
     
     public func create(withFrame frame: CGRect, viewIdentifier viewId: Int64, arguments args: Any?) -> FlutterPlatformView {
         let arguments = args as? NSDictionary
+        
+        if let headlessWebViewId = arguments?["headlessWebViewId"] as? String,
+           let headlessWebView = HeadlessInAppWebViewManager.webViews[headlessWebViewId],
+           let platformView = headlessWebView?.disposeAndGetFlutterWebView(withFrame: frame) {
+            return platformView
+        }
+        
         let webviewController = FlutterWebViewController(registrar: registrar!,
                                                          withFrame: frame,
                                                          viewIdentifier: viewId,

ios/Classes/InAppWebView/InAppWebView.swift

@@ -1570,9 +1570,11 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
         let origin = "\(origin.protocol)://\(origin.host)\(origin.port != 0 ? ":" + String(origin.port) : "")"
         let permissionRequest = PermissionRequest(origin: origin, resources: [type.rawValue], frame: frame)
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.PermissionRequestCallback()
         callback.nonNullSuccess = { (response: PermissionResponse) in
             if let action = response.action {
+                decisionHandlerCalled = true
                 switch action {
                     case 1:
                         decisionHandler(.grant)
@@ -1588,7 +1590,10 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: PermissionResponse?) in
-            decisionHandler(.deny)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(.deny)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))
@@ -1610,9 +1615,11 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
         let origin = "\(origin.protocol)://\(origin.host)\(origin.port != 0 ? ":" + String(origin.port) : "")"
         let permissionRequest = PermissionRequest(origin: origin, resources: ["deviceOrientationAndMotion"], frame: frame)
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.PermissionRequestCallback()
         callback.nonNullSuccess = { (response: PermissionResponse) in
             if let action = response.action {
+                decisionHandlerCalled = true
                 switch action {
                     case 1:
                         decisionHandler(.grant)
@@ -1628,7 +1635,10 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: PermissionResponse?) in
-            decisionHandler(.deny)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(.deny)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))
@@ -1694,13 +1704,18 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return
         }
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.ShouldOverrideUrlLoadingCallback()
         callback.nonNullSuccess = { (response: WKNavigationActionPolicy) in
+            decisionHandlerCalled = true
             decisionHandler(response)
             return false
         }
         callback.defaultBehaviour = { (response: WKNavigationActionPolicy?) in
-            decisionHandler(.allow)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(.allow)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))
@@ -1726,13 +1741,18 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
         let useOnNavigationResponse = settings?.useOnNavigationResponse
         
         if useOnNavigationResponse != nil, useOnNavigationResponse! {
+            var decisionHandlerCalled = false
             let callback = WebViewChannelDelegate.NavigationResponseCallback()
             callback.nonNullSuccess = { (response: WKNavigationResponsePolicy) in
+                decisionHandlerCalled = true
                 decisionHandler(response)
                 return false
             }
             callback.defaultBehaviour = { (response: WKNavigationResponsePolicy?) in
-                decisionHandler(.allow)
+                if !decisionHandlerCalled {
+                    decisionHandlerCalled = true
+                    decisionHandler(.allow)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1747,7 +1767,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
         }
         
         if let useOnDownloadStart = settings?.useOnDownloadStart, useOnDownloadStart {
-            if #available(iOS 14.5, *), !navigationResponse.canShowMIMEType {
+            if #available(iOS 14.5, *), !navigationResponse.canShowMIMEType, useOnNavigationResponse == nil || !useOnNavigationResponse! {
                 decisionHandler(.download)
                 return
             } else {
@@ -1856,6 +1876,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return
         }
         
+        var completionHandlerCalled = false
         if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodHTTPBasic ||
             challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodDefault ||
             challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodHTTPDigest ||
@@ -1869,6 +1890,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             let callback = WebViewChannelDelegate.ReceivedHttpAuthRequestCallback()
             callback.nonNullSuccess = { (response: HttpAuthResponse) in
                 if let action = response.action {
+                    completionHandlerCalled = true
                     switch action {
                         case 0:
                             InAppWebView.credentialsProposed = []
@@ -1917,7 +1939,10 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
                 return true
             }
             callback.defaultBehaviour = { (response: HttpAuthResponse?) in
-                completionHandler(.performDefaultHandling, nil)
+                if !completionHandlerCalled {
+                    completionHandlerCalled = true
+                    completionHandler(.performDefaultHandling, nil)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1944,6 +1969,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             let callback = WebViewChannelDelegate.ReceivedServerTrustAuthRequestCallback()
             callback.nonNullSuccess = { (response: ServerTrustAuthResponse) in
                 if let action = response.action {
+                    completionHandlerCalled = true
                     switch action {
                         case 0:
                             InAppWebView.credentialsProposed = []
@@ -1964,7 +1990,10 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
                 return true
             }
             callback.defaultBehaviour = { (response: ServerTrustAuthResponse?) in
-                completionHandler(.performDefaultHandling, nil)
+                if !completionHandlerCalled {
+                    completionHandlerCalled = true
+                    completionHandler(.performDefaultHandling, nil)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1981,6 +2010,7 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             let callback = WebViewChannelDelegate.ReceivedClientCertRequestCallback()
             callback.nonNullSuccess = { (response: ClientCertResponse) in
                 if let action = response.action {
+                    completionHandlerCalled = true
                     switch action {
                         case 0:
                             completionHandler(.cancelAuthenticationChallenge, nil)
@@ -2017,7 +2047,10 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
                 return true
             }
             callback.defaultBehaviour = { (response: ClientCertResponse?) in
-                completionHandler(.performDefaultHandling, nil)
+                if !completionHandlerCalled {
+                    completionHandlerCalled = true
+                    completionHandler(.performDefaultHandling, nil)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -2102,9 +2135,12 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return
         }
         
+        var completionHandlerCalled = false
+        
         let callback = WebViewChannelDelegate.JsAlertCallback()
         callback.nonNullSuccess = { (response: JsAlertResponse) in
             if response.handledByClient {
+                completionHandlerCalled = true
                 let action = response.action ?? 1
                 switch action {
                     case 0:
@@ -2118,14 +2154,20 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: JsAlertResponse?) in
-            let responseMessage = response?.message
+            if !completionHandlerCalled {
-            let confirmButtonTitle = response?.confirmButtonTitle
+                completionHandlerCalled = true
-            self.createAlertDialog(message: message, responseMessage: responseMessage,
+                let responseMessage = response?.message
-                                   confirmButtonTitle: confirmButtonTitle, completionHandler: completionHandler)
+                let confirmButtonTitle = response?.confirmButtonTitle
+                self.createAlertDialog(message: message, responseMessage: responseMessage,
+                                       confirmButtonTitle: confirmButtonTitle, completionHandler: completionHandler)
+            }
         }
         callback.error = { (code: String, message: String?, details: Any?) in
-            print(code + ", " + (message ?? ""))
+            if !completionHandlerCalled {
-            completionHandler()
+                completionHandlerCalled = true
+                print(code + ", " + (message ?? ""))
+                completionHandler()
+            }
         }
         
         if let channelDelegate = channelDelegate {
@@ -2159,9 +2201,12 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
     
     public func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo,
                  completionHandler: @escaping (Bool) -> Void) {
+        var completionHandlerCalled = false
+        
         let callback = WebViewChannelDelegate.JsConfirmCallback()
         callback.nonNullSuccess = { (response: JsConfirmResponse) in
             if response.handledByClient {
+                completionHandlerCalled = true
                 let action = response.action ?? 1
                 switch action {
                     case 0:
@@ -2178,14 +2223,20 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: JsConfirmResponse?) in
-            let responseMessage = response?.message
+            if !completionHandlerCalled {
-            let confirmButtonTitle = response?.confirmButtonTitle
+                completionHandlerCalled = true
-            let cancelButtonTitle = response?.cancelButtonTitle
+                let responseMessage = response?.message
-            self.createConfirmDialog(message: message, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle, cancelButtonTitle: cancelButtonTitle, completionHandler: completionHandler)
+                let confirmButtonTitle = response?.confirmButtonTitle
+                let cancelButtonTitle = response?.cancelButtonTitle
+                self.createConfirmDialog(message: message, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle, cancelButtonTitle: cancelButtonTitle, completionHandler: completionHandler)
+            }
         }
         callback.error = { (code: String, message: String?, details: Any?) in
-            print(code + ", " + (message ?? ""))
+            if !completionHandlerCalled {
-            completionHandler(false)
+                completionHandlerCalled = true
+                print(code + ", " + (message ?? ""))
+                completionHandler(false)
+            }
         }
         
         if let channelDelegate = channelDelegate {
@@ -2230,9 +2281,13 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
     
     public func webView(_ webView: WKWebView, runJavaScriptTextInputPanelWithPrompt message: String, defaultText defaultValue: String?, initiatedByFrame frame: WKFrameInfo,
                  completionHandler: @escaping (String?) -> Void) {
+        
+        var completionHandlerCalled = false
+        
         let callback = WebViewChannelDelegate.JsPromptCallback()
         callback.nonNullSuccess = { (response: JsPromptResponse) in
             if response.handledByClient {
+                completionHandlerCalled = true
                 let action = response.action ?? 1
                 switch action {
                     case 0:
@@ -2249,16 +2304,22 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: JsPromptResponse?) in
-            let responseMessage = response?.message
+            if !completionHandlerCalled {
-            let confirmButtonTitle = response?.confirmButtonTitle
+                completionHandlerCalled = true
-            let cancelButtonTitle = response?.cancelButtonTitle
+                let responseMessage = response?.message
-            let value = response?.value
+                let confirmButtonTitle = response?.confirmButtonTitle
-            self.createPromptDialog(message: message, defaultValue: defaultValue, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle,
+                let cancelButtonTitle = response?.cancelButtonTitle
-                                    cancelButtonTitle: cancelButtonTitle, value: value, completionHandler: completionHandler)
+                let value = response?.value
+                self.createPromptDialog(message: message, defaultValue: defaultValue, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle,
+                                        cancelButtonTitle: cancelButtonTitle, value: value, completionHandler: completionHandler)
+            }
         }
         callback.error = { (code: String, message: String?, details: Any?) in
-            print(code + ", " + (message ?? ""))
+            if !completionHandlerCalled {
-            completionHandler(nil)
+                completionHandlerCalled = true
+                print(code + ", " + (message ?? ""))
+                completionHandler(nil)
+            }
         }
         
         if let channelDelegate = channelDelegate {
@@ -2375,13 +2436,18 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             return
         }
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.ShouldAllowDeprecatedTLSCallback()
         callback.nonNullSuccess = { (action: Bool) in
+            decisionHandlerCalled = true
             decisionHandler(action)
             return false
         }
         callback.defaultBehaviour = { (action: Bool?) in
-            decisionHandler(false)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(false)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))

ios/Classes/InAppWebView/WebViewChannelDelegate.swift

@@ -740,6 +740,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return JsAlertResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onJsAlert(url: URL?, message: String, isMainFrame: Bool, callback: JsAlertCallback) {
@@ -762,6 +766,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return JsConfirmResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onJsConfirm(url: URL?, message: String, isMainFrame: Bool, callback: JsConfirmCallback) {
@@ -784,6 +792,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return JsPromptResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onJsPrompt(url: URL?, message: String, defaultValue: String?, isMainFrame: Bool, callback: JsPromptCallback) {
@@ -851,6 +863,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return PermissionResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onPermissionRequest(request: PermissionRequest, callback: PermissionRequestCallback) {
@@ -871,6 +887,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return WKNavigationActionPolicy.cancel
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func shouldOverrideUrlLoading(navigationAction: WKNavigationAction, callback: ShouldOverrideUrlLoadingCallback) {
@@ -922,6 +942,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return HttpAuthResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onReceivedHttpAuthRequest(challenge: HttpAuthenticationChallenge, callback: ReceivedHttpAuthRequestCallback) {
@@ -939,6 +963,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return ServerTrustAuthResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onReceivedServerTrustAuthRequest(challenge: ServerTrustChallenge, callback: ReceivedServerTrustAuthRequestCallback) {
@@ -956,6 +984,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return ClientCertResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onReceivedClientCertRequest(challenge: ClientCertChallenge, callback: ReceivedClientCertRequestCallback) {
@@ -1030,6 +1062,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return WKNavigationResponsePolicy.cancel
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onNavigationResponse(navigationResponse: WKNavigationResponse, callback: NavigationResponseCallback) {
@@ -1050,6 +1086,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return false
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func shouldAllowDeprecatedTLS(challenge: URLAuthenticationChallenge, callback: ShouldAllowDeprecatedTLSCallback) {

lib/assets/web/web_support.js

@@ -5,6 +5,7 @@ window.flutter_inappwebview = {
             viewId: viewId,
             iframeId: iframeId,
             iframe: null,
+            iframeContainer: null,
             windowAutoincrementId: 0,
             windows: {},
             isFullscreen: false,
@@ -19,6 +20,7 @@ window.flutter_inappwebview = {
             prepare: function(settings) {
                 webView.settings = settings;
                 var iframe = document.getElementById(iframeId);
+                var iframeContainer = document.getElementById(iframeId + '-container');
 
                 document.addEventListener('fullscreenchange', function(event) {
                     // document.fullscreenElement will point to the element that
@@ -37,6 +39,7 @@ window.flutter_inappwebview = {
 
                 if (iframe != null) {
                     webView.iframe = iframe;
+                    webView.iframeContainer = iframeContainer;
                     iframe.addEventListener('load', function (event) {
                         webView.windowAutoincrementId = 0;
                         webView.windows = {};
@@ -543,20 +546,20 @@ window.flutter_inappwebview = {
                 return false;
             },
             getSize: function() {
-                var iframe = webView.iframe;
+                var iframeContainer = webView.iframeContainer;
                 var width = 0.0;
                 var height = 0.0;
-                if (iframe.style.width != null && iframe.style.width != '' && iframe.style.width.indexOf('px') > 0) {
+                if (iframeContainer.style.width != null && iframeContainer.style.width != '' && iframeContainer.style.width.indexOf('px') > 0) {
-                    width = parseFloat(iframe.style.width);
+                    width = parseFloat(iframeContainer.style.width);
                 }
                 if (width == null || width == 0.0) {
-                    width = iframe.getBoundingClientRect().width;
+                    width = iframeContainer.getBoundingClientRect().width;
                 }
-                if (iframe.style.height != null && iframe.style.height != '' && iframe.style.height.indexOf('px') > 0) {
+                if (iframeContainer.style.height != null && iframeContainer.style.height != '' && iframeContainer.style.height.indexOf('px') > 0) {
-                    height = parseFloat(iframe.style.height);
+                    height = parseFloat(iframeContainer.style.height);
                 }
                 if (height == null || height == 0.0) {
-                    height = iframe.getBoundingClientRect().height;
+                    height = iframeContainer.getBoundingClientRect().height;
                 }
 
                 return {

lib/src/chrome_safari_browser/chrome_safari_browser.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:collection';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';

lib/src/in_app_browser/in_app_browser.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:collection';
+import 'dart:typed_data';
 
 import 'package:flutter/services.dart';
 

lib/src/in_app_webview/apple/in_app_webview_controller.dart

@@ -1,4 +1,5 @@
 import 'dart:core';
+import 'dart:typed_data';
 
 import 'package:flutter/services.dart';
 

lib/src/in_app_webview/headless_in_app_webview.dart

@@ -1,4 +1,6 @@
 import 'dart:collection';
+import 'dart:typed_data';
+import 'dart:ui';
 
 import 'package:flutter/services.dart';
 import 'package:flutter_inappwebview/src/util.dart';
@@ -714,3 +716,10 @@ class HeadlessInAppWebView implements WebView, Disposable {
     MediaCaptureState? newState,
   )? onMicrophoneCaptureStateChanged;
 }
+
+extension InternalHeadlessInAppWebView on HeadlessInAppWebView {
+  Future<void> internalDispose() async {
+    _started = false;
+    _running = false;
+  }
+}

lib/src/in_app_webview/in_app_webview.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:collection';
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
@@ -7,6 +8,8 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter/gestures.dart';
+import 'package:flutter_inappwebview/src/in_app_webview/headless_in_app_webview.dart';
+import 'package:flutter_inappwebview/src/util.dart';
 
 import '../find_interaction/find_interaction_controller.dart';
 import '../web/web_platform_manager.dart';
@@ -37,9 +40,21 @@ class InAppWebView extends StatefulWidget implements WebView {
   final Set<Factory<OneSequenceGestureRecognizer>>? gestureRecognizers;
 
   ///The window id of a [CreateWindowAction.windowId].
+  ///
+  ///**Supported Platforms/Implementations**:
+  ///- Android native WebView
+  ///- iOS
   @override
   final int? windowId;
 
+  ///The [HeadlessInAppWebView] to use to initialize this widget
+  ///
+  ///**Supported Platforms/Implementations**:
+  ///- Android native WebView
+  ///- iOS
+  ///- Web
+  final HeadlessInAppWebView? headlessWebView;
+
   const InAppWebView({
     Key? key,
     this.windowId,
@@ -148,6 +163,7 @@ class InAppWebView extends StatefulWidget implements WebView {
     this.onCameraCaptureStateChanged,
     this.onMicrophoneCaptureStateChanged,
     this.gestureRecognizers,
+    this.headlessWebView,
   }) : super(key: key);
 
   @override
@@ -609,8 +625,11 @@ class _InAppWebViewState extends State<InAppWebView> {
           webViewHtmlElement.initialUrlRequest = widget.initialUrlRequest;
           webViewHtmlElement.initialFile = widget.initialFile;
           webViewHtmlElement.initialData = widget.initialData;
+          webViewHtmlElement.headlessWebViewId = widget.headlessWebView?.isRunning() ?? false ? widget.headlessWebView?.id : null;
           webViewHtmlElement.prepare();
-          webViewHtmlElement.makeInitialLoad();
+          if (webViewHtmlElement.headlessWebViewId == null) {
+            webViewHtmlElement.makeInitialLoad();
+          }
           _onPlatformViewCreated(viewId);
         },
       );
@@ -653,6 +672,7 @@ class _InAppWebViewState extends State<InAppWebView> {
                 'initialSettings': initialSettings,
                 'contextMenu': widget.contextMenu?.toMap() ?? {},
                 'windowId': widget.windowId,
+                'headlessWebViewId': widget.headlessWebView?.isRunning() ?? false ? widget.headlessWebView?.id : null,
                 'implementation': widget.implementation.toNativeValue(),
                 'initialUserScripts':
                     widget.initialUserScripts?.map((e) => e.toMap()).toList() ??
@@ -680,6 +700,7 @@ class _InAppWebViewState extends State<InAppWebView> {
             'initialSettings': initialSettings,
             'contextMenu': widget.contextMenu?.toMap() ?? {},
             'windowId': widget.windowId,
+            'headlessWebViewId': widget.headlessWebView?.isRunning() ?? false ? widget.headlessWebView?.id : null,
             'implementation': widget.implementation.toNativeValue(),
             'initialUserScripts':
                 widget.initialUserScripts?.map((e) => e.toMap()).toList() ?? [],
@@ -702,6 +723,7 @@ class _InAppWebViewState extends State<InAppWebView> {
           'initialSettings': initialSettings,
           'contextMenu': widget.contextMenu?.toMap() ?? {},
           'windowId': widget.windowId,
+          'headlessWebViewId': widget.headlessWebView?.isRunning() ?? false ? widget.headlessWebView?.id : null,
           'implementation': widget.implementation.toNativeValue(),
           'initialUserScripts':
               widget.initialUserScripts?.map((e) => e.toMap()).toList() ?? [],
@@ -732,10 +754,19 @@ class _InAppWebViewState extends State<InAppWebView> {
   }
 
   void _onPlatformViewCreated(int id) {
-    _controller = InAppWebViewController(id, widget);
+    final viewId = (!kIsWeb && (widget.headlessWebView?.isRunning() ?? false)) ? widget.headlessWebView?.id : id;
-    widget.pullToRefreshController?.initMethodChannel(id);
+    widget.headlessWebView?.internalDispose();
-    widget.findInteractionController?.initMethodChannel(id);
+    _controller = InAppWebViewController(viewId, widget);
+    widget.pullToRefreshController?.initMethodChannel(viewId);
+    widget.findInteractionController?.initMethodChannel(viewId);
     if (widget.onWebViewCreated != null) {
+      debugLog(
+          className: "InAppWebView",
+          name: "WebView",
+          id: viewId?.toString(),
+          debugLoggingSettings: WebView.debugLoggingSettings,
+          method: "onWebViewCreated",
+          args: []);
       widget.onWebViewCreated!(_controller!);
     }
   }

lib/src/in_app_webview/in_app_webview_controller.dart

@@ -3,6 +3,8 @@ import 'dart:collection';
 import 'dart:convert';
 import 'dart:core';
 import 'dart:developer' as developer;
+import 'dart:typed_data';
+import 'dart:ui';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';

lib/src/in_app_webview/main.dart

@@ -7,7 +7,7 @@ export 'in_app_webview_settings.dart'
         InAppWebViewGroupOptions,
         WebViewOptions,
         InAppWebViewOptions;
-export 'headless_in_app_webview.dart';
+export 'headless_in_app_webview.dart' hide InternalHeadlessInAppWebView;
 export 'android/main.dart';
 export 'apple/main.dart';
 export '../find_interaction/find_interaction_controller.dart';

lib/src/pull_to_refresh/pull_to_refresh_controller.dart

@@ -1,3 +1,5 @@
+import 'dart:ui';
+
 import 'package:flutter/services.dart';
 import '../in_app_webview/webview.dart';
 import '../in_app_browser/in_app_browser.dart';

lib/src/util.dart

@@ -1,5 +1,6 @@
 import 'dart:math';
 import 'dart:developer' as developer;
+import 'dart:typed_data';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';

lib/src/web/headless_in_app_web_view_web_element.dart

@@ -1,6 +1,8 @@
 import 'dart:async';
+import 'dart:ui';
 import 'package:flutter/services.dart';
 
+import 'headless_inappwebview_manager.dart';
 import 'in_app_web_view_web_element.dart';
 import '../util.dart';
 import '../types/disposable.dart';
@@ -59,14 +61,21 @@ class HeadlessInAppWebViewWebElement implements Disposable {
   }
 
   void setSize(Size size) {
-    webView?.iframe.style.width = size.width.toString() + "px";
+    webView?.iframeContainer.style.width = size.width.toString() + "px";
-    webView?.iframe.style.height = size.height.toString() + "px";
+    webView?.iframeContainer.style.height = size.height.toString() + "px";
+  }
+
+  InAppWebViewWebElement? disposeAndGetFlutterWebView() {
+    InAppWebViewWebElement? newFlutterWebView = webView;
+    dispose();
+    return newFlutterWebView;
   }
 
   @override
   void dispose() {
     _channel?.setMethodCallHandler(null);
     _channel = null;
+    HeadlessInAppWebViewManager.webViews.putIfAbsent(id, () => null);
     webView?.dispose();
     webView = null;
   }

lib/src/web/headless_inappwebview_manager.dart

@@ -9,6 +9,8 @@ import 'headless_in_app_web_view_web_element.dart';
 import '../types/main.dart';
 
 class HeadlessInAppWebViewManager {
+  static final Map<String, HeadlessInAppWebViewWebElement?> webViews = {};
+
   static late MethodChannel _sharedChannel;
 
   late BinaryMessenger _messenger;
@@ -50,17 +52,18 @@ class HeadlessInAppWebViewManager {
     var headlessWebView = HeadlessInAppWebViewWebElement(
         id: id, messenger: _messenger, webView: webView);
     WebPlatformManager.webViews.putIfAbsent(id, () => webView);
+    HeadlessInAppWebViewManager.webViews.putIfAbsent(id, () => headlessWebView);
     prepare(webView, params);
     headlessWebView.onWebViewCreated();
     webView.makeInitialLoad();
   }
 
   void prepare(InAppWebViewWebElement webView, Map<String, dynamic> params) {
-    webView.iframe.style.display = 'none';
+    webView.iframeContainer.style.display = 'none';
     Map<String, num>? initialSize = params["initialSize"]?.cast<String, num>();
     if (initialSize != null) {
-      webView.iframe.style.width = initialSize["width"].toString() + 'px';
+      webView.iframeContainer.style.width = initialSize["width"].toString() + 'px';
-      webView.iframe.style.height = initialSize["height"].toString() + 'px';
+      webView.iframeContainer.style.height = initialSize["height"].toString() + 'px';
     }
     Map<String, dynamic> initialSettings =
         params["initialSettings"].cast<String, dynamic>();
@@ -74,7 +77,7 @@ class HeadlessInAppWebViewManager {
     webView.initialFile = params["initialFile"];
     webView.initialData = InAppWebViewInitialData.fromMap(
         params["initialData"]?.cast<String, dynamic>());
-    document.body?.append(webView.iframe);
+    document.body?.append(webView.iframeContainer);
     webView.prepare();
   }
 }

lib/src/web/in_app_web_view_web_element.dart

@@ -1,8 +1,11 @@
 import 'dart:async';
+import 'dart:typed_data';
+import 'dart:ui';
 import 'package:flutter/services.dart';
 import 'dart:html';
 import 'dart:js' as js;
 
+import 'headless_inappwebview_manager.dart';
 import 'web_platform_manager.dart';
 import '../in_app_webview/in_app_webview_settings.dart';
 import '../types/main.dart';
@@ -11,14 +14,16 @@ import '../types/disposable.dart';
 class InAppWebViewWebElement implements Disposable {
   late dynamic _viewId;
   late BinaryMessenger _messenger;
+  late DivElement iframeContainer;
   late IFrameElement iframe;
   late MethodChannel? _channel;
   InAppWebViewSettings? initialSettings;
   URLRequest? initialUrlRequest;
   InAppWebViewInitialData? initialData;
   String? initialFile;
+  String? headlessWebViewId;
 
-  late InAppWebViewSettings settings;
+  InAppWebViewSettings? settings;
   late js.JsObject bridgeJsObject;
   bool isLoading = false;
 
@@ -26,11 +31,17 @@ class InAppWebViewWebElement implements Disposable {
       {required dynamic viewId, required BinaryMessenger messenger}) {
     this._viewId = viewId;
     this._messenger = messenger;
+    iframeContainer = DivElement()
+      ..id = 'flutter_inappwebview-$_viewId-container'
+      ..style.height = '100%'
+      ..style.width = '100%'
+      ..style.border = 'none';
     iframe = IFrameElement()
       ..id = 'flutter_inappwebview-$_viewId'
       ..style.height = '100%'
       ..style.width = '100%'
       ..style.border = 'none';
+    iframeContainer.append(iframe);
 
     _channel = MethodChannel(
       'com.pichillilorenzo/flutter_inappwebview_$_viewId',
@@ -173,35 +184,59 @@ class InAppWebViewWebElement implements Disposable {
   }
 
   void prepare() {
-    settings = initialSettings ?? InAppWebViewSettings();
+    if (headlessWebViewId != null) {
+      final headlessWebView = HeadlessInAppWebViewManager.webViews[headlessWebViewId!];
+      if (headlessWebView != null && headlessWebView.webView != null) {
+        final webView = headlessWebView.disposeAndGetFlutterWebView();
+        if (webView != null) {
+          webView.iframe.id = iframe.id;
+          iframe.remove();
+          iframeContainer.append(webView.iframe);
+          iframe = webView.iframe;
 
-    Set<Sandbox> sandbox = Set.from(Sandbox.values);
+          initialSettings = webView.initialSettings;
+          settings = webView.settings;
+          initialUrlRequest = webView.initialUrlRequest;
+          initialData = webView.initialData;
+          initialFile = webView.initialFile;
 
-    if (settings.javaScriptEnabled != null && !settings.javaScriptEnabled!) {
+          bridgeJsObject['webViews'][_viewId] = bridgeJsObject
-      sandbox.remove(Sandbox.ALLOW_SCRIPTS);
+              .callMethod("createFlutterInAppWebView", [_viewId, iframe.id]);
+        }
+      }
     }
 
-    iframe.allow = settings.iframeAllow ?? iframe.allow;
+    if (headlessWebViewId == null && settings == null) {
-    iframe.allowFullscreen =
+      settings = initialSettings ?? InAppWebViewSettings();
-        settings.iframeAllowFullscreen ?? iframe.allowFullscreen;
-    iframe.referrerPolicy =
-        settings.iframeReferrerPolicy?.toNativeValue() ?? iframe.referrerPolicy;
-    iframe.name = settings.iframeName ?? iframe.name;
-    iframe.csp = settings.iframeCsp ?? iframe.csp;
 
-    if (settings.iframeSandbox != null &&
+      Set<Sandbox> sandbox = Set.from(Sandbox.values);
-        settings.iframeSandbox != Sandbox.ALLOW_ALL) {
+
-      iframe.setAttribute("sandbox",
+      if (settings!.javaScriptEnabled != null && !settings!.javaScriptEnabled!) {
-          settings.iframeSandbox!.map((e) => e.toNativeValue()).join(" "));
+        sandbox.remove(Sandbox.ALLOW_SCRIPTS);
-    } else if (settings.iframeSandbox == Sandbox.ALLOW_ALL) {
+      }
-      iframe.removeAttribute("sandbox");
+
-    } else if (sandbox != Sandbox.values) {
+      iframe.allow = settings!.iframeAllow ?? iframe.allow;
-      iframe.setAttribute(
+      iframe.allowFullscreen =
-          "sandbox", sandbox.map((e) => e.toNativeValue()).join(" "));
+          settings!.iframeAllowFullscreen ?? iframe.allowFullscreen;
-      settings.iframeSandbox = sandbox;
+      iframe.referrerPolicy =
+          settings!.iframeReferrerPolicy?.toNativeValue() ?? iframe.referrerPolicy;
+      iframe.name = settings!.iframeName ?? iframe.name;
+      iframe.csp = settings!.iframeCsp ?? iframe.csp;
+
+      if (settings!.iframeSandbox != null &&
+          settings!.iframeSandbox != Sandbox.ALLOW_ALL) {
+        iframe.setAttribute("sandbox",
+            settings!.iframeSandbox!.map((e) => e.toNativeValue()).join(" "));
+      } else if (settings!.iframeSandbox == Sandbox.ALLOW_ALL) {
+        iframe.removeAttribute("sandbox");
+      } else if (sandbox != Sandbox.values) {
+        iframe.setAttribute(
+            "sandbox", sandbox.map((e) => e.toNativeValue()).join(" "));
+        settings!.iframeSandbox = sandbox;
+      }
     }
 
-    _callMethod("prepare", [js.JsObject.jsify(settings.toMap())]);
+    _callMethod("prepare", [js.JsObject.jsify(settings!.toMap())]);
   }
 
   dynamic _callMethod(Object method, [List? args]) {
@@ -405,7 +440,7 @@ class InAppWebViewWebElement implements Disposable {
     Set<Sandbox> sandbox = getSandbox();
 
     if (newSettings.javaScriptEnabled != null &&
-        settings.javaScriptEnabled != newSettings.javaScriptEnabled) {
+        settings!.javaScriptEnabled != newSettings.javaScriptEnabled) {
       if (!newSettings.javaScriptEnabled!) {
         sandbox.remove(Sandbox.ALLOW_SCRIPTS);
       } else {
@@ -413,23 +448,23 @@ class InAppWebViewWebElement implements Disposable {
       }
     }
 
-    if (settings.iframeAllow != newSettings.iframeAllow) {
+    if (settings!.iframeAllow != newSettings.iframeAllow) {
       iframe.allow = newSettings.iframeAllow;
     }
-    if (settings.iframeAllowFullscreen != newSettings.iframeAllowFullscreen) {
+    if (settings!.iframeAllowFullscreen != newSettings.iframeAllowFullscreen) {
       iframe.allowFullscreen = newSettings.iframeAllowFullscreen;
     }
-    if (settings.iframeReferrerPolicy != newSettings.iframeReferrerPolicy) {
+    if (settings!.iframeReferrerPolicy != newSettings.iframeReferrerPolicy) {
       iframe.referrerPolicy = newSettings.iframeReferrerPolicy?.toNativeValue();
     }
-    if (settings.iframeName != newSettings.iframeName) {
+    if (settings!.iframeName != newSettings.iframeName) {
       iframe.name = newSettings.iframeName;
     }
-    if (settings.iframeCsp != newSettings.iframeCsp) {
+    if (settings!.iframeCsp != newSettings.iframeCsp) {
       iframe.csp = newSettings.iframeCsp;
     }
 
-    if (settings.iframeSandbox != newSettings.iframeSandbox) {
+    if (settings!.iframeSandbox != newSettings.iframeSandbox) {
       var sandbox = newSettings.iframeSandbox;
       if (sandbox != null && sandbox != Sandbox.ALLOW_ALL) {
         iframe.setAttribute(
@@ -449,7 +484,7 @@ class InAppWebViewWebElement implements Disposable {
   }
 
   Future<Map<String, dynamic>> getSettings() async {
-    return settings.toMap();
+    return settings!.toMap();
   }
 
   void onLoadStart(String url) async {
@@ -569,7 +604,7 @@ class InAppWebViewWebElement implements Disposable {
   void dispose() {
     _channel?.setMethodCallHandler(null);
     _channel = null;
-    iframe.remove();
+    iframeContainer.remove();
     if (WebPlatformManager.webViews.containsKey(_viewId)) {
       WebPlatformManager.webViews.remove(_viewId);
     }

lib/src/web/web_platform.dart

@@ -19,7 +19,7 @@ class FlutterInAppWebViewWebPlatform {
       var webView =
           InAppWebViewWebElement(viewId: viewId, messenger: registrar);
       WebPlatformManager.webViews.putIfAbsent(viewId, () => webView);
-      return webView.iframe;
+      return webView.iframeContainer;
     });
   }
 

macos/Classes/HeadlessInAppWebView/HeadlessInAppWebView.swift

@@ -54,6 +54,20 @@ public class HeadlessInAppWebView : Disposable {
         return nil
     }
     
+    public func disposeAndGetFlutterWebView(withFrame frame: CGRect) -> FlutterWebViewController? {
+        let newFlutterWebView = flutterWebView
+        if let view = flutterWebView?.view() {
+            // restore WebView frame and alpha
+            view.frame = frame
+            view.alphaValue = 1.0
+            // remove from parent
+            view.removeFromSuperview()
+            dispose()
+        }
+        return newFlutterWebView
+    }
+    
+    
     public func dispose() {
         channelDelegate?.dispose()
         channelDelegate = nil

macos/Classes/InAppWebView/FlutterWebViewFactory.swift

@@ -25,6 +25,13 @@ public class FlutterWebViewFactory: NSObject, FlutterPlatformViewFactory {
     
     public func create(withViewIdentifier viewId: Int64, arguments args: Any?) -> NSView {
         let arguments = args as? NSDictionary
+        
+        if let headlessWebViewId = arguments?["headlessWebViewId"] as? String,
+           let headlessWebView = HeadlessInAppWebViewManager.webViews[headlessWebViewId],
+           let platformView = headlessWebView?.disposeAndGetFlutterWebView(withFrame: .zero) {
+            return platformView.view()
+        }
+        
         let webviewController = FlutterWebViewController(registrar: registrar!,
                                                          withFrame: .zero,
                                                          viewIdentifier: viewId,

macos/Classes/InAppWebView/InAppWebView.swift

@@ -1073,9 +1073,11 @@ public class InAppWebView: WKWebView, WKUIDelegate,
         let origin = "\(origin.protocol)://\(origin.host)\(origin.port != 0 ? ":" + String(origin.port) : "")"
         let permissionRequest = PermissionRequest(origin: origin, resources: [type.rawValue], frame: frame)
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.PermissionRequestCallback()
         callback.nonNullSuccess = { (response: PermissionResponse) in
             if let action = response.action {
+                decisionHandlerCalled = true
                 switch action {
                     case 1:
                         decisionHandler(.grant)
@@ -1091,7 +1093,10 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: PermissionResponse?) in
-            decisionHandler(.deny)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(.deny)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))
@@ -1157,13 +1162,18 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return
         }
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.ShouldOverrideUrlLoadingCallback()
         callback.nonNullSuccess = { (response: WKNavigationActionPolicy) in
+            decisionHandlerCalled = true
             decisionHandler(response)
             return false
         }
         callback.defaultBehaviour = { (response: WKNavigationActionPolicy?) in
-            decisionHandler(.allow)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(.allow)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))
@@ -1189,13 +1199,18 @@ public class InAppWebView: WKWebView, WKUIDelegate,
         let useOnNavigationResponse = settings?.useOnNavigationResponse
         
         if useOnNavigationResponse != nil, useOnNavigationResponse! {
+            var decisionHandlerCalled = false
             let callback = WebViewChannelDelegate.NavigationResponseCallback()
             callback.nonNullSuccess = { (response: WKNavigationResponsePolicy) in
+                decisionHandlerCalled = true
                 decisionHandler(response)
                 return false
             }
             callback.defaultBehaviour = { (response: WKNavigationResponsePolicy?) in
-                decisionHandler(.allow)
+                if !decisionHandlerCalled {
+                    decisionHandlerCalled = true
+                    decisionHandler(.allow)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1210,7 +1225,7 @@ public class InAppWebView: WKWebView, WKUIDelegate,
         }
         
         if let useOnDownloadStart = settings?.useOnDownloadStart, useOnDownloadStart {
-            if #available(macOS 11.3, *), !navigationResponse.canShowMIMEType {
+            if #available(macOS 11.3, *), !navigationResponse.canShowMIMEType, useOnNavigationResponse == nil || !useOnNavigationResponse! {
                 decisionHandler(.download)
                 return
             } else {
@@ -1310,6 +1325,7 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return
         }
         
+        var completionHandlerCalled = false
         if challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodHTTPBasic ||
             challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodDefault ||
             challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodHTTPDigest ||
@@ -1323,6 +1339,7 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             let callback = WebViewChannelDelegate.ReceivedHttpAuthRequestCallback()
             callback.nonNullSuccess = { (response: HttpAuthResponse) in
                 if let action = response.action {
+                    completionHandlerCalled = true
                     switch action {
                         case 0:
                             InAppWebView.credentialsProposed = []
@@ -1371,7 +1388,10 @@ public class InAppWebView: WKWebView, WKUIDelegate,
                 return true
             }
             callback.defaultBehaviour = { (response: HttpAuthResponse?) in
-                completionHandler(.performDefaultHandling, nil)
+                if !completionHandlerCalled {
+                    completionHandlerCalled = true
+                    completionHandler(.performDefaultHandling, nil)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1398,6 +1418,7 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             let callback = WebViewChannelDelegate.ReceivedServerTrustAuthRequestCallback()
             callback.nonNullSuccess = { (response: ServerTrustAuthResponse) in
                 if let action = response.action {
+                    completionHandlerCalled = true
                     switch action {
                         case 0:
                             InAppWebView.credentialsProposed = []
@@ -1418,7 +1439,10 @@ public class InAppWebView: WKWebView, WKUIDelegate,
                 return true
             }
             callback.defaultBehaviour = { (response: ServerTrustAuthResponse?) in
-                completionHandler(.performDefaultHandling, nil)
+                if !completionHandlerCalled {
+                    completionHandlerCalled = true
+                    completionHandler(.performDefaultHandling, nil)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1435,6 +1459,7 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             let callback = WebViewChannelDelegate.ReceivedClientCertRequestCallback()
             callback.nonNullSuccess = { (response: ClientCertResponse) in
                 if let action = response.action {
+                    completionHandlerCalled = true
                     switch action {
                         case 0:
                             completionHandler(.cancelAuthenticationChallenge, nil)
@@ -1471,7 +1496,10 @@ public class InAppWebView: WKWebView, WKUIDelegate,
                 return true
             }
             callback.defaultBehaviour = { (response: ClientCertResponse?) in
-                completionHandler(.performDefaultHandling, nil)
+                if !completionHandlerCalled {
+                    completionHandlerCalled = true
+                    completionHandler(.performDefaultHandling, nil)
+                }
             }
             callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
                 print(code + ", " + (message ?? ""))
@@ -1573,9 +1601,12 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return
         }
         
+        var completionHandlerCalled = false
+        
         let callback = WebViewChannelDelegate.JsAlertCallback()
         callback.nonNullSuccess = { (response: JsAlertResponse) in
             if response.handledByClient {
+                completionHandlerCalled = true
                 let action = response.action ?? 1
                 switch action {
                     case 0:
@@ -1589,14 +1620,20 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: JsAlertResponse?) in
-            let responseMessage = response?.message
+            if !completionHandlerCalled {
-            let confirmButtonTitle = response?.confirmButtonTitle
+                completionHandlerCalled = true
-            self.createAlertDialog(message: message, responseMessage: responseMessage,
+                let responseMessage = response?.message
-                                   confirmButtonTitle: confirmButtonTitle, completionHandler: completionHandler)
+                let confirmButtonTitle = response?.confirmButtonTitle
+                self.createAlertDialog(message: message, responseMessage: responseMessage,
+                                       confirmButtonTitle: confirmButtonTitle, completionHandler: completionHandler)
+            }
         }
         callback.error = { (code: String, message: String?, details: Any?) in
-            print(code + ", " + (message ?? ""))
+            if !completionHandlerCalled {
-            completionHandler()
+                completionHandlerCalled = true
+                print(code + ", " + (message ?? ""))
+                completionHandler()
+            }
         }
         
         if let channelDelegate = channelDelegate {
@@ -1622,9 +1659,12 @@ public class InAppWebView: WKWebView, WKUIDelegate,
     
     public func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo,
                  completionHandler: @escaping (Bool) -> Void) {
+        var completionHandlerCalled = false
+        
         let callback = WebViewChannelDelegate.JsConfirmCallback()
         callback.nonNullSuccess = { (response: JsConfirmResponse) in
             if response.handledByClient {
+                completionHandlerCalled = true
                 let action = response.action ?? 1
                 switch action {
                     case 0:
@@ -1641,14 +1681,20 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: JsConfirmResponse?) in
-            let responseMessage = response?.message
+            if !completionHandlerCalled {
-            let confirmButtonTitle = response?.confirmButtonTitle
+                completionHandlerCalled = true
-            let cancelButtonTitle = response?.cancelButtonTitle
+                let responseMessage = response?.message
-            self.createConfirmDialog(message: message, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle, cancelButtonTitle: cancelButtonTitle, completionHandler: completionHandler)
+                let confirmButtonTitle = response?.confirmButtonTitle
+                let cancelButtonTitle = response?.cancelButtonTitle
+                self.createConfirmDialog(message: message, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle, cancelButtonTitle: cancelButtonTitle, completionHandler: completionHandler)
+            }
         }
         callback.error = { (code: String, message: String?, details: Any?) in
-            print(code + ", " + (message ?? ""))
+            if !completionHandlerCalled {
-            completionHandler(false)
+                completionHandlerCalled = true
+                print(code + ", " + (message ?? ""))
+                completionHandler(false)
+            }
         }
         
         if let channelDelegate = channelDelegate {
@@ -1678,9 +1724,13 @@ public class InAppWebView: WKWebView, WKUIDelegate,
     
     public func webView(_ webView: WKWebView, runJavaScriptTextInputPanelWithPrompt message: String, defaultText defaultValue: String?, initiatedByFrame frame: WKFrameInfo,
                  completionHandler: @escaping (String?) -> Void) {
+        
+        var completionHandlerCalled = false
+        
         let callback = WebViewChannelDelegate.JsPromptCallback()
         callback.nonNullSuccess = { (response: JsPromptResponse) in
             if response.handledByClient {
+                completionHandlerCalled = true
                 let action = response.action ?? 1
                 switch action {
                     case 0:
@@ -1697,16 +1747,22 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return true
         }
         callback.defaultBehaviour = { (response: JsPromptResponse?) in
-            let responseMessage = response?.message
+            if !completionHandlerCalled {
-            let confirmButtonTitle = response?.confirmButtonTitle
+                completionHandlerCalled = true
-            let cancelButtonTitle = response?.cancelButtonTitle
+                let responseMessage = response?.message
-            let value = response?.value
+                let confirmButtonTitle = response?.confirmButtonTitle
-            self.createPromptDialog(message: message, defaultValue: defaultValue, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle,
+                let cancelButtonTitle = response?.cancelButtonTitle
-                                    cancelButtonTitle: cancelButtonTitle, value: value, completionHandler: completionHandler)
+                let value = response?.value
+                self.createPromptDialog(message: message, defaultValue: defaultValue, responseMessage: responseMessage, confirmButtonTitle: confirmButtonTitle,
+                                        cancelButtonTitle: cancelButtonTitle, value: value, completionHandler: completionHandler)
+            }
         }
         callback.error = { (code: String, message: String?, details: Any?) in
-            print(code + ", " + (message ?? ""))
+            if !completionHandlerCalled {
-            completionHandler(nil)
+                completionHandlerCalled = true
+                print(code + ", " + (message ?? ""))
+                completionHandler(nil)
+            }
         }
         
         if let channelDelegate = channelDelegate {
@@ -1768,13 +1824,18 @@ public class InAppWebView: WKWebView, WKUIDelegate,
             return
         }
         
+        var decisionHandlerCalled = false
         let callback = WebViewChannelDelegate.ShouldAllowDeprecatedTLSCallback()
         callback.nonNullSuccess = { (action: Bool) in
+            decisionHandlerCalled = true
             decisionHandler(action)
             return false
         }
         callback.defaultBehaviour = { (action: Bool?) in
-            decisionHandler(false)
+            if !decisionHandlerCalled {
+                decisionHandlerCalled = true
+                decisionHandler(false)
+            }
         }
         callback.error = { [weak callback] (code: String, message: String?, details: Any?) in
             print(code + ", " + (message ?? ""))

macos/Classes/InAppWebView/WebViewChannelDelegate.swift

@@ -834,6 +834,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return PermissionResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onPermissionRequest(request: PermissionRequest, callback: PermissionRequestCallback) {
@@ -854,6 +858,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return WKNavigationActionPolicy.cancel
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func shouldOverrideUrlLoading(navigationAction: WKNavigationAction, callback: ShouldOverrideUrlLoadingCallback) {
@@ -905,6 +913,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return HttpAuthResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onReceivedHttpAuthRequest(challenge: HttpAuthenticationChallenge, callback: ReceivedHttpAuthRequestCallback) {
@@ -922,6 +934,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return ServerTrustAuthResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onReceivedServerTrustAuthRequest(challenge: ServerTrustChallenge, callback: ReceivedServerTrustAuthRequestCallback) {
@@ -939,6 +955,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return ClientCertResponse.fromMap(map: obj as? [String:Any?])
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onReceivedClientCertRequest(challenge: ClientCertChallenge, callback: ReceivedClientCertRequestCallback) {
@@ -1013,6 +1033,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return WKNavigationResponsePolicy.cancel
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func onNavigationResponse(navigationResponse: WKNavigationResponse, callback: NavigationResponseCallback) {
@@ -1033,6 +1057,10 @@ public class WebViewChannelDelegate : ChannelDelegate {
                 return false
             }
         }
+        
+        deinit {
+            self.defaultBehaviour(nil)
+        }
     }
     
     public func shouldAllowDeprecatedTLS(challenge: URLAuthenticationChallenge, callback: ShouldAllowDeprecatedTLSCallback) {

pubspec.yaml

@@ -1,6 +1,6 @@
 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: 6.0.0-beta.3
+version: 6.0.0-beta.4
 homepage: https://inappwebview.dev/
 repository: https://github.com/pichillilorenzo/flutter_inappwebview
 issue_tracker: https://github.com/pichillilorenzo/flutter_inappwebview/issues