[webview_flutter_android][webview_flutter_wkwebview] Fixes bug where PlatformWebViewWidget doesn't rebuild when the controller changes (#4533)

In a scenario where a `WebViewWidget` was updated with a new `WebViewController`, the native `WebView` from the new controller would not be shown. e.g.

```dart
 class WebViewExample extends StatefulWidget {
  const WebViewExample({super.key});

  @override
  State<WebViewExample> createState() => _WebViewExampleState();
}

class _WebViewExampleState extends State<WebViewExample> {
  late WebViewController controller;

  @override
  void initState() {
    super.initState();
    controller = WebViewController()
      ..loadRequest(Uri.parse('https://flutter.dev'));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Flutter Simple Example')),
      body: WebViewWidget(controller: controller),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          setState(() {
            controller = WebViewController()
              ..loadRequest(Uri.parse('https://google.com'));
          });
        },
        child: const Icon(Icons.add),
      ),
    );
  }
}                                                                                                                                                                                                    
```

From testing, the `WebViewWidget` would continue showing the original `WebViewController` and eventually freeze the PlatformView preventing button presses. 

This is because the PlatformView widget only creates the native PlatformView once and doesn't recreate it when the creation parameters change (as expected). This adds a default `key` to the `PlatformWebViewWidget` that is used to indicate when the underlying widget needs to be removed and recreated. See https://api.flutter.dev/flutter/widgets/Widget/key.html

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 3.9.2
+
+* Fixes bug where `PlatformWebViewWidget` doesn't rebuild when the controller or PlatformView
+  implementation flag changes. 
+
 ## 3.9.1
 
 * Adjusts SDK checks for better testability.

packages/webview_flutter/webview_flutter_android/lib/src/android_webview_controller.dart

@@ -744,6 +744,25 @@ class AndroidWebViewWidgetCreationParams
   ///
   /// Defaults to false.
   final bool displayWithHybridComposition;
+
+  @override
+  int get hashCode => Object.hash(
+        controller,
+        layoutDirection,
+        displayWithHybridComposition,
+        platformViewsServiceProxy,
+        instanceManager,
+      );
+
+  @override
+  bool operator ==(Object other) {
+    return other is AndroidWebViewWidgetCreationParams &&
+        controller == other.controller &&
+        layoutDirection == other.layoutDirection &&
+        displayWithHybridComposition == other.displayWithHybridComposition &&
+        platformViewsServiceProxy == other.platformViewsServiceProxy &&
+        instanceManager == other.instanceManager;
+  }
 }
 
 /// An implementation of [PlatformWebViewWidget] with the Android WebView API.
@@ -763,7 +782,9 @@ class AndroidWebViewWidget extends PlatformWebViewWidget {
   @override
   Widget build(BuildContext context) {
     return PlatformViewLink(
-      key: _androidParams.key,
+      // Setting a default key using `params` ensures the `PlatformViewLink`
+      // recreates the PlatformView when changes are made.
+      key: _androidParams.key ?? ObjectKey(params),
       viewType: 'plugins.flutter.io/webview',
       surfaceFactory: (
         BuildContext context,

packages/webview_flutter/webview_flutter_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_android
 description: A Flutter plugin that provides a WebView widget on Android.
 repository: https://github.com/flutter/packages/tree/main/packages/webview_flutter/webview_flutter_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 3.9.1
+version: 3.9.2
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

packages/webview_flutter/webview_flutter_android/test/android_webview_controller_test.dart

@@ -1216,5 +1216,68 @@ void main() {
         ),
       );
     });
+
+    testWidgets('PlatformView is recreated when the controller changes',
+        (WidgetTester tester) async {
+      final MockPlatformViewsServiceProxy mockPlatformViewsService =
+          MockPlatformViewsServiceProxy();
+
+      when(
+        mockPlatformViewsService.initSurfaceAndroidView(
+          id: anyNamed('id'),
+          viewType: anyNamed('viewType'),
+          layoutDirection: anyNamed('layoutDirection'),
+          creationParams: anyNamed('creationParams'),
+          creationParamsCodec: anyNamed('creationParamsCodec'),
+          onFocus: anyNamed('onFocus'),
+        ),
+      ).thenReturn(MockSurfaceAndroidViewController());
+
+      await tester.pumpWidget(Builder(
+        builder: (BuildContext context) {
+          return AndroidWebViewWidget(
+            AndroidWebViewWidgetCreationParams(
+              controller: createControllerWithMocks(),
+              platformViewsServiceProxy: mockPlatformViewsService,
+            ),
+          ).build(context);
+        },
+      ));
+      await tester.pumpAndSettle();
+
+      verify(
+        mockPlatformViewsService.initSurfaceAndroidView(
+          id: anyNamed('id'),
+          viewType: anyNamed('viewType'),
+          layoutDirection: anyNamed('layoutDirection'),
+          creationParams: anyNamed('creationParams'),
+          creationParamsCodec: anyNamed('creationParamsCodec'),
+          onFocus: anyNamed('onFocus'),
+        ),
+      );
+
+      await tester.pumpWidget(Builder(
+        builder: (BuildContext context) {
+          return AndroidWebViewWidget(
+            AndroidWebViewWidgetCreationParams(
+              controller: createControllerWithMocks(),
+              platformViewsServiceProxy: mockPlatformViewsService,
+            ),
+          ).build(context);
+        },
+      ));
+      await tester.pumpAndSettle();
+
+      verify(
+        mockPlatformViewsService.initSurfaceAndroidView(
+          id: anyNamed('id'),
+          viewType: anyNamed('viewType'),
+          layoutDirection: anyNamed('layoutDirection'),
+          creationParams: anyNamed('creationParams'),
+          creationParamsCodec: anyNamed('creationParamsCodec'),
+          onFocus: anyNamed('onFocus'),
+        ),
+      );
+    });
   });
 }

packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.7.2
+
+* Fixes bug where `PlatformWebViewWidget` doesn't rebuild when the controller changes.
+
 ## 3.7.1
 
 * Updates pigeon version to `10.1.4`.

packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart

@@ -632,6 +632,21 @@ class WebKitWebViewWidgetCreationParams
   // Maintains instances used to communicate with the native objects they
   // represent.
   final InstanceManager _instanceManager;
+
+  @override
+  int get hashCode => Object.hash(
+        controller,
+        layoutDirection,
+        _instanceManager,
+      );
+
+  @override
+  bool operator ==(Object other) {
+    return other is WebKitWebViewWidgetCreationParams &&
+        controller == other.controller &&
+        layoutDirection == other.layoutDirection &&
+        _instanceManager == other._instanceManager;
+  }
 }
 
 /// An implementation of [PlatformWebViewWidget] with the WebKit api.
@@ -651,7 +666,9 @@ class WebKitWebViewWidget extends PlatformWebViewWidget {
   @override
   Widget build(BuildContext context) {
     return UiKitView(
-      key: _webKitParams.key,
+      // Setting a default key using `params` ensures the `UIKitView` recreates
+      // the PlatformView when changes are made.
+      key: _webKitParams.key ?? ObjectKey(params),
       viewType: 'plugins.flutter.io/webview',
       onPlatformViewCreated: (_) {},
       layoutDirection: params.layoutDirection,

packages/webview_flutter/webview_flutter_wkwebview/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_wkwebview
 description: A Flutter plugin that provides a WebView widget based on Apple's WKWebView control.
 repository: https://github.com/flutter/packages/tree/main/packages/webview_flutter/webview_flutter_wkwebview
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 3.7.1
+version: 3.7.2
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

packages/webview_flutter/webview_flutter_wkwebview/test/webkit_webview_widget_test.dart

@@ -24,37 +24,8 @@ void main() {
         onWeakReferenceRemoved: (_) {},
       );
 
-      final WebKitWebViewController controller = WebKitWebViewController(
+      final WebKitWebViewController controller =
-        WebKitWebViewControllerCreationParams(
+          createTestWebViewController(testInstanceManager);
-          webKitProxy: WebKitProxy(createWebView: (
-            WKWebViewConfiguration configuration, {
-            void Function(
-              String keyPath,
-              NSObject object,
-              Map<NSKeyValueChangeKey, Object?> change,
-            )? observeValue,
-            InstanceManager? instanceManager,
-          }) {
-            final WKWebView webView = WKWebView.detached(
-              instanceManager: testInstanceManager,
-            );
-            testInstanceManager.addDartCreatedInstance(webView);
-            return webView;
-          }, createWebViewConfiguration: ({InstanceManager? instanceManager}) {
-            return MockWKWebViewConfiguration();
-          }, createUIDelegate: ({
-            dynamic onCreateWebView,
-            dynamic requestMediaCapturePermission,
-            InstanceManager? instanceManager,
-          }) {
-            final MockWKUIDelegate mockWKUIDelegate = MockWKUIDelegate();
-            when(mockWKUIDelegate.copy()).thenReturn(MockWKUIDelegate());
-
-            testInstanceManager.addDartCreatedInstance(mockWKUIDelegate);
-            return mockWKUIDelegate;
-          }),
-        ),
-      );
 
       final WebKitWebViewWidget widget = WebKitWebViewWidget(
         WebKitWebViewWidgetCreationParams(
@@ -71,5 +42,86 @@ void main() {
       expect(find.byType(UiKitView), findsOneWidget);
       expect(find.byKey(const Key('keyValue')), findsOneWidget);
     });
+
+    testWidgets('Key of the PlatformView changes when the controller changes',
+        (WidgetTester tester) async {
+      final InstanceManager testInstanceManager = InstanceManager(
+        onWeakReferenceRemoved: (_) {},
+      );
+
+      // Pump WebViewWidget with first controller.
+      final WebKitWebViewController controller1 =
+          createTestWebViewController(testInstanceManager);
+      final WebKitWebViewWidget webViewWidget = WebKitWebViewWidget(
+        WebKitWebViewWidgetCreationParams(
+          controller: controller1,
+          instanceManager: testInstanceManager,
+        ),
+      );
+
+      await tester.pumpWidget(
+        Builder(
+          builder: (BuildContext context) => webViewWidget.build(context),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.byKey(ObjectKey(webViewWidget.params)), findsOneWidget);
+
+      // Pump WebViewWidget with second controller.
+      final WebKitWebViewController controller2 =
+          createTestWebViewController(testInstanceManager);
+      final WebKitWebViewWidget webViewWidget2 = WebKitWebViewWidget(
+        WebKitWebViewWidgetCreationParams(
+          controller: controller2,
+          instanceManager: testInstanceManager,
+        ),
+      );
+
+      await tester.pumpWidget(
+        Builder(
+          builder: (BuildContext context) => webViewWidget2.build(context),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.byKey(ObjectKey(webViewWidget2.params)), findsOneWidget);
+    });
   });
 }
+
+WebKitWebViewController createTestWebViewController(
+  InstanceManager testInstanceManager,
+) {
+  return WebKitWebViewController(
+    WebKitWebViewControllerCreationParams(
+      webKitProxy: WebKitProxy(createWebView: (
+        WKWebViewConfiguration configuration, {
+        void Function(
+          String keyPath,
+          NSObject object,
+          Map<NSKeyValueChangeKey, Object?> change,
+        )? observeValue,
+        InstanceManager? instanceManager,
+      }) {
+        final WKWebView webView = WKWebView.detached(
+          instanceManager: testInstanceManager,
+        );
+        testInstanceManager.addDartCreatedInstance(webView);
+        return webView;
+      }, createWebViewConfiguration: ({InstanceManager? instanceManager}) {
+        return MockWKWebViewConfiguration();
+      }, createUIDelegate: ({
+        dynamic onCreateWebView,
+        dynamic requestMediaCapturePermission,
+        InstanceManager? instanceManager,
+      }) {
+        final MockWKUIDelegate mockWKUIDelegate = MockWKUIDelegate();
+        when(mockWKUIDelegate.copy()).thenReturn(MockWKUIDelegate());
+
+        testInstanceManager.addDartCreatedInstance(mockWKUIDelegate);
+        return mockWKUIDelegate;
+      }),
+    ),
+  );
+}