Guard against usage after async callbacks in RenderAndroidView, unregister listener (#108496)

dnfield · web-flow · commit 0cc7db54ce5c · 2022-07-28T18:36:04.000Z
diff --git a/packages/flutter/lib/src/rendering/platform_view.dart b/packages/flutter/lib/src/rendering/platform_view.dart
@@ -109,6 +109,7 @@ class RenderAndroidView extends PlatformViewRenderBox {
   /// Sets a new Android view controller.
   @override
   set controller(AndroidViewController controller) {
+    assert(!_isDisposed);
     assert(_viewController != null);
     assert(controller != null);
     if (_viewController == controller) {
@@ -140,6 +141,7 @@ class RenderAndroidView extends PlatformViewRenderBox {
   }
 
   void _onPlatformViewCreated(int id) {
+    assert(!_isDisposed);
     markNeedsSemanticsUpdate();
   }
 
@@ -179,8 +181,14 @@ class RenderAndroidView extends PlatformViewRenderBox {
       targetSize = size;
       if (_viewController.isCreated) {
         _currentTextureSize = await _viewController.setSize(targetSize);
+        if (_isDisposed) {
+          return;
+        }
       } else {
         await _viewController.create(size: targetSize);
+        if (_isDisposed) {
+          return;
+        }
         _currentTextureSize = targetSize;
       }
       // We've resized the platform view to targetSize, but it is possible that
@@ -248,6 +256,7 @@ class RenderAndroidView extends PlatformViewRenderBox {
   void dispose() {
     _isDisposed = true;
     _clipRectLayer.layer = null;
+    _viewController.removeOnPlatformViewCreatedListener(_onPlatformViewCreated);
     super.dispose();
   }
 
diff --git a/packages/flutter/test/rendering/platform_view_test.dart b/packages/flutter/test/rendering/platform_view_test.dart
@@ -221,6 +221,45 @@ void main() {
       expect(renderBox.debugLayer!.firstChild, isA<TextureLayer>());
     });
   });
+
+  test('markNeedsPaint does not get called on a disposed RO', () async {
+    FakeAsync().run((FakeAsync async) {
+      final AndroidViewController viewController =
+        PlatformViewsService.initAndroidView(id: 0, viewType: 'webview', layoutDirection: TextDirection.rtl);
+      final RenderAndroidView renderBox = RenderAndroidView(
+        viewController: viewController,
+        hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+        gestureRecognizers: <Factory<OneSequenceGestureRecognizer>>{},
+      );
+
+      final Completer<void> viewCreation = Completer<void>();
+      const MethodChannel channel = MethodChannel('flutter/platform_views');
+      binding.defaultBinaryMessenger.setMockMethodCallHandler(channel, (MethodCall methodCall) async {
+        assert(methodCall.method == 'create', 'Unexpected method call');
+        await viewCreation.future;
+        return /*textureId=*/ 0;
+      });
+
+      layout(renderBox);
+      pumpFrame(phase: EnginePhase.paint);
+
+      expect(renderBox.debugLayer, isNotNull);
+      expect(renderBox.debugLayer!.hasChildren, isFalse);
+      expect(viewController.isCreated, isFalse);
+      expect(renderBox.debugNeedsPaint, isFalse);
+
+      renderBox.dispose();
+      viewCreation.complete();
+      async.flushMicrotasks();
+
+      expect(viewController.isCreated, isTrue);
+      expect(renderBox.debugNeedsPaint, isFalse);
+      expect(renderBox.debugLayer, isNull);
+
+      pumpFrame(phase: EnginePhase.paint);
+      expect(renderBox.debugLayer, isNull);
+    });
+  });
 }
 
 ui.PointerData _pointerData(
diff --git a/packages/flutter/test/services/fake_platform_views.dart b/packages/flutter/test/services/fake_platform_views.dart
@@ -101,9 +101,7 @@ class FakeAndroidViewController implements AndroidViewController {
   }
 
   @override
-  void removeOnPlatformViewCreatedListener(PlatformViewCreatedCallback listener) {
-    throw UnimplementedError();
-  }
+  void removeOnPlatformViewCreatedListener(PlatformViewCreatedCallback listener) {}
 
   @override
   Future<void> sendMotionEvent(AndroidMotionEvent event) {

Original file line number	Diff line number	Diff line change
`@@ -101,9 +101,7 @@ class FakeAndroidViewController implements AndroidViewController {`
`101`	`101`	`}`
`102`	`102`
`103`	`103`	`@override`
`104`		`- void removeOnPlatformViewCreatedListener(PlatformViewCreatedCallback listener) {`
`105`		`- throw UnimplementedError();`
`106`		`- }`
	`104`	`+ void removeOnPlatformViewCreatedListener(PlatformViewCreatedCallback listener) {}`
`107`	`105`
`108`	`106`	`@override`
`109`	`107`	`Future<void> sendMotionEvent(AndroidMotionEvent event) {`