[webview_flutter_wkwebview][webview_flutter_android] Fixes bug where the WebViews could not be released

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 3.2.3
+
+* Fixes bug that prevented the web view from being garbage collected.
+* Fixes bug causing a `LateInitializationError` when a `PlatformNavigationDelegate` is not provided.
+
 ## 3.2.2
 
 * Updates example code for `use_build_context_synchronously` lint.

packages/webview_flutter/webview_flutter_android/example/integration_test/webview_flutter_test.dart

@@ -17,6 +17,8 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:integration_test/integration_test.dart';
+import 'package:webview_flutter_android/src/android_webview.dart' as android;
+import 'package:webview_flutter_android/src/android_webview_api_impls.dart';
 import 'package:webview_flutter_android/src/instance_manager.dart';
 import 'package:webview_flutter_android/src/weak_reference_utils.dart';
 import 'package:webview_flutter_android/webview_flutter_android.dart';
@@ -58,15 +60,13 @@ Future<void> main() async {
       )
       ..loadRequest(LoadRequestParams(uri: Uri.parse(primaryUrl)));
 
-    await tester.pumpWidget(
-      Builder(
-        builder: (BuildContext context) {
-          return PlatformWebViewWidget(
-            PlatformWebViewWidgetCreationParams(controller: controller),
-          ).build(context);
-        },
-      ),
-    );
+    await tester.pumpWidget(Builder(
+      builder: (BuildContext context) {
+        return PlatformWebViewWidget(
+          PlatformWebViewWidgetCreationParams(controller: controller),
+        ).build(context);
+      },
+    ));
 
     await pageFinished.future;
 
@@ -96,6 +96,79 @@ Future<void> main() async {
     expect(gcIdentifier, 0);
   }, timeout: const Timeout(Duration(seconds: 10)));
 
+  testWidgets(
+    'WebView is released by garbage collection',
+    (WidgetTester tester) async {
+      final Completer<void> webViewGCCompleter = Completer<void>();
+
+      late final InstanceManager instanceManager;
+      instanceManager =
+          InstanceManager(onWeakReferenceRemoved: (int identifier) {
+        final Copyable instance =
+            instanceManager.getInstanceWithWeakReference(identifier)!;
+        if (instance is android.WebView && !webViewGCCompleter.isCompleted) {
+          webViewGCCompleter.complete();
+        }
+      });
+
+      android.WebView.api = WebViewHostApiImpl(
+        instanceManager: instanceManager,
+      );
+      android.WebSettings.api = WebSettingsHostApiImpl(
+        instanceManager: instanceManager,
+      );
+      android.WebChromeClient.api = WebChromeClientHostApiImpl(
+        instanceManager: instanceManager,
+      );
+
+      await tester.pumpWidget(
+        Builder(
+          builder: (BuildContext context) {
+            return PlatformWebViewWidget(
+              AndroidWebViewWidgetCreationParams(
+                instanceManager: instanceManager,
+                controller: PlatformWebViewController(
+                  const PlatformWebViewControllerCreationParams(),
+                ),
+              ),
+            ).build(context);
+          },
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.pumpWidget(
+        Builder(
+          builder: (BuildContext context) {
+            return PlatformWebViewWidget(
+              AndroidWebViewWidgetCreationParams(
+                instanceManager: instanceManager,
+                controller: PlatformWebViewController(
+                  const PlatformWebViewControllerCreationParams(),
+                ),
+              ),
+            ).build(context);
+          },
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // Force garbage collection.
+      await IntegrationTestWidgetsFlutterBinding.instance
+          .watchPerformance(() async {
+        await tester.pumpAndSettle();
+      });
+
+      await tester.pumpAndSettle();
+      await expectLater(webViewGCCompleter.future, completes);
+
+      android.WebView.api = WebViewHostApiImpl();
+      android.WebSettings.api = WebSettingsHostApiImpl();
+      android.WebChromeClient.api = WebChromeClientHostApiImpl();
+    },
+    timeout: const Timeout(Duration(seconds: 10)),
+  );
+
   testWidgets('runJavaScriptReturningResult', (WidgetTester tester) async {
     final Completer<void> pageFinished = Completer<void>();
 
@@ -110,15 +183,13 @@ Future<void> main() async {
       )
       ..loadRequest(LoadRequestParams(uri: Uri.parse(primaryUrl)));
 
-    await tester.pumpWidget(
-      Builder(
-        builder: (BuildContext context) {
-          return PlatformWebViewWidget(
-            PlatformWebViewWidgetCreationParams(controller: controller),
-          ).build(context);
-        },
-      ),
-    );
+    await tester.pumpWidget(Builder(
+      builder: (BuildContext context) {
+        return PlatformWebViewWidget(
+          PlatformWebViewWidgetCreationParams(controller: controller),
+        ).build(context);
+      },
+    ));
 
     await pageFinished.future;
 
@@ -151,15 +222,13 @@ Future<void> main() async {
         ),
       );
 
-    await tester.pumpWidget(
-      Builder(
-        builder: (BuildContext context) {
-          return PlatformWebViewWidget(
-            PlatformWebViewWidgetCreationParams(controller: controller),
-          ).build(context);
-        },
-      ),
-    );
+    await tester.pumpWidget(Builder(
+      builder: (BuildContext context) {
+        return PlatformWebViewWidget(
+          PlatformWebViewWidgetCreationParams(controller: controller),
+        ).build(context);
+      },
+    ));
 
     await pageLoads.stream.firstWhere((String url) => url == headersUrl);
 
@@ -195,15 +264,13 @@ Future<void> main() async {
       'data:text/html;charset=utf-8;base64,PCFET0NUWVBFIGh0bWw+',
     );
 
-    await tester.pumpWidget(
-      Builder(
-        builder: (BuildContext context) {
-          return PlatformWebViewWidget(
-            PlatformWebViewWidgetCreationParams(controller: controller),
-          ).build(context);
-        },
-      ),
-    );
+    await tester.pumpWidget(Builder(
+      builder: (BuildContext context) {
+        return PlatformWebViewWidget(
+          PlatformWebViewWidgetCreationParams(controller: controller),
+        ).build(context);
+      },
+    ));
 
     await pageFinished.future;
 
@@ -258,15 +325,13 @@ Future<void> main() async {
       ..setUserAgent('Custom_User_Agent1')
       ..loadRequest(LoadRequestParams(uri: Uri.parse('about:blank')));
 
-    await tester.pumpWidget(
-      Builder(
-        builder: (BuildContext context) {
-          return PlatformWebViewWidget(
-            PlatformWebViewWidgetCreationParams(controller: controller),
-          ).build(context);
-        },
-      ),
-    );
+    await tester.pumpWidget(Builder(
+      builder: (BuildContext context) {
+        return PlatformWebViewWidget(
+          PlatformWebViewWidgetCreationParams(controller: controller),
+        ).build(context);
+      },
+    ));
 
     await pageFinished.future;
 
@@ -335,15 +400,13 @@ Future<void> main() async {
           ),
         );
 
-      await tester.pumpWidget(
-        Builder(
-          builder: (BuildContext context) {
-            return PlatformWebViewWidget(
-              PlatformWebViewWidgetCreationParams(controller: controller),
-            ).build(context);
-          },
-        ),
-      );
+      await tester.pumpWidget(Builder(
+        builder: (BuildContext context) {
+          return PlatformWebViewWidget(
+            PlatformWebViewWidgetCreationParams(controller: controller),
+          ).build(context);
+        },
+      ));
 
       await pageLoaded.future;
 
@@ -369,15 +432,13 @@ Future<void> main() async {
           ),
         );
 
-      await tester.pumpWidget(
-        Builder(
-          builder: (BuildContext context) {
-            return PlatformWebViewWidget(
-              PlatformWebViewWidgetCreationParams(controller: controller),
-            ).build(context);
-          },
-        ),
-      );
+      await tester.pumpWidget(Builder(
+        builder: (BuildContext context) {
+          return PlatformWebViewWidget(
+            PlatformWebViewWidgetCreationParams(controller: controller),
+          ).build(context);
+        },
+      ));
 
       await pageLoaded.future;
 
@@ -491,15 +552,13 @@ Future<void> main() async {
           ),
         );
 
-      await tester.pumpWidget(
-        Builder(
-          builder: (BuildContext context) {
-            return PlatformWebViewWidget(
-              PlatformWebViewWidgetCreationParams(controller: controller),
-            ).build(context);
-          },
-        ),
-      );
+      await tester.pumpWidget(Builder(
+        builder: (BuildContext context) {
+          return PlatformWebViewWidget(
+            PlatformWebViewWidgetCreationParams(controller: controller),
+          ).build(context);
+        },
+      ));
 
       await pageLoaded.future;
 
@@ -525,15 +584,13 @@ Future<void> main() async {
           ),
         );
 
-      await tester.pumpWidget(
-        Builder(
-          builder: (BuildContext context) {
-            return PlatformWebViewWidget(
-              PlatformWebViewWidgetCreationParams(controller: controller),
-            ).build(context);
-          },
-        ),
-      );
+      await tester.pumpWidget(Builder(
+        builder: (BuildContext context) {
+          return PlatformWebViewWidget(
+            PlatformWebViewWidgetCreationParams(controller: controller),
+          ).build(context);
+        },
+      ));
 
       await pageLoaded.future;
 
@@ -573,15 +630,13 @@ Future<void> main() async {
         ),
       );
 
-    await tester.pumpWidget(
-      Builder(
-        builder: (BuildContext context) {
-          return PlatformWebViewWidget(
-            PlatformWebViewWidgetCreationParams(controller: controller),
-          ).build(context);
-        },
-      ),
-    );
+    await tester.pumpWidget(Builder(
+      builder: (BuildContext context) {
+        return PlatformWebViewWidget(
+          PlatformWebViewWidgetCreationParams(controller: controller),
+        ).build(context);
+      },
+    ));
 
     await pageLoaded.future;
 

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

@@ -96,28 +96,30 @@ class AndroidWebViewController extends PlatformWebViewController {
   );
 
   late final android_webview.WebChromeClient _webChromeClient =
-      withWeakReferenceTo(this,
-          (WeakReference<AndroidWebViewController> weakReference) {
-    return _androidWebViewParams.androidWebViewProxy
-        .createAndroidWebChromeClient(
-      onProgressChanged: (android_webview.WebView webView, int progress) {
-        if (weakReference.target?._currentNavigationDelegate._onProgress !=
+      _androidWebViewParams.androidWebViewProxy.createAndroidWebChromeClient(
+    onProgressChanged: withWeakReferenceTo(this,
+        (WeakReference<AndroidWebViewController> weakReference) {
+      return (android_webview.WebView webView, int progress) {
+        if (weakReference.target?._currentNavigationDelegate?._onProgress !=
             null) {
           weakReference
-              .target!._currentNavigationDelegate._onProgress!(progress);
+              .target!._currentNavigationDelegate!._onProgress!(progress);
         }
-      },
-      onShowFileChooser: (android_webview.WebView webView,
+      };
+    }),
+    onShowFileChooser: withWeakReferenceTo(this,
+        (WeakReference<AndroidWebViewController> weakReference) {
+      return (android_webview.WebView webView,
           android_webview.FileChooserParams params) async {
         if (weakReference.target?._onShowFileSelectorCallback != null) {
           return weakReference.target!._onShowFileSelectorCallback!(
             FileSelectorParams._fromFileChooserParams(params),
           );
         }
         return <String>[];
-      },
-    );
-  });
+      };
+    }),
+  );
 
   /// The native [android_webview.FlutterAssetManager] allows managing assets.
   late final android_webview.FlutterAssetManager _flutterAssetManager =
@@ -126,10 +128,7 @@ class AndroidWebViewController extends PlatformWebViewController {
   final Map<String, AndroidJavaScriptChannelParams> _javaScriptChannelParams =
       <String, AndroidJavaScriptChannelParams>{};
 
-  // The keeps a reference to the current NavigationDelegate so that the
-  // callback methods remain reachable.
-  // ignore: unused_field
-  late AndroidNavigationDelegate _currentNavigationDelegate;
+  AndroidNavigationDelegate? _currentNavigationDelegate;
 
   Future<List<String>> Function(FileSelectorParams)?
       _onShowFileSelectorCallback;

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/plugins/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: 3.2.2
+version: 3.2.3
 
 environment:
   sdk: ">=2.17.0 <3.0.0"