Revert 20917 platform view arena (#21086)

This reverts commit c594696f.

packages/flutter/lib/src/rendering/platform_view.dart

@@ -42,13 +42,7 @@ enum _PlatformViewState {
 /// Android [View](https://developer.android.com/reference/android/view/View).
 ///
 /// The render object's layout behavior is to fill all available space, the parent of this object must
-/// provide bounded layout constraints.
-///
-/// RenderAndroidView participates in Flutter's [GestureArena]s, and dispatches touch events to the
-/// Android view iff it won the arena. Specific gestures that should be dispatched to the Android
-/// view can be specified in [RenderAndroidView.gestureRecognizers]. If
-/// [RenderAndroidView.gestureRecognizers] is empty, the gesture will be dispatched to the Android
-/// view iff it was not claimed by any other gesture recognizer.
+/// provide bounded layout constraints
 ///
 /// See also:
 ///  * [AndroidView] which is a widget that is used to show an Android view.
@@ -59,14 +53,10 @@ class RenderAndroidView extends RenderBox {
   RenderAndroidView({
     @required AndroidViewController viewController,
     @required this.hitTestBehavior,
-    List<OneSequenceGestureRecognizer> gestureRecognizers = const <OneSequenceGestureRecognizer> [],
   }) : assert(viewController != null),
        assert(hitTestBehavior != null),
-       assert(gestureRecognizers != null),
-       _viewController = viewController
-  {
+       _viewController = viewController {
     _motionEventsDispatcher = new _MotionEventsDispatcher(globalToLocal, viewController);
-    this.gestureRecognizers = gestureRecognizers;
   }
 
   _PlatformViewState _state = _PlatformViewState.uninitialized;
@@ -90,18 +80,6 @@ class RenderAndroidView extends RenderBox {
   // any newly arriving events there's nothing we need to invalidate.
   PlatformViewHitTestBehavior hitTestBehavior;
 
-  /// Which gestures should be forwarded to the Android view.
-  ///
-  /// The gesture recognizers on this list participate in the gesture arena for each pointer
-  /// that was put down on the render box. If any of the recognizers on this list wins the
-  /// gesture arena, the entire pointer event sequence starting from the pointer down event
-  /// will be dispatched to the Android view.
-  set gestureRecognizers(List<OneSequenceGestureRecognizer> recognizers) {
-    assert(recognizers != null);
-    _gestureRecognizer?.dispose();
-    _gestureRecognizer = new _AndroidViewGestureRecognizer(_motionEventsDispatcher, recognizers);
-  }
-
   @override
   bool get sizedByParent => true;
 
@@ -113,8 +91,6 @@ class RenderAndroidView extends RenderBox {
 
   _MotionEventsDispatcher _motionEventsDispatcher;
 
-  _AndroidViewGestureRecognizer _gestureRecognizer;
-
   @override
   void performResize() {
     size = constraints.biggest;
@@ -193,109 +169,7 @@ class RenderAndroidView extends RenderBox {
 
   @override
   void handleEvent(PointerEvent event, HitTestEntry entry) {
-    if (event is PointerDownEvent) {
-      _gestureRecognizer.addPointer(event);
-    }
-  }
-
-  @override
-  void detach() {
-    _gestureRecognizer.reset();
-    super.detach();
-  }
-}
-
-class _AndroidViewGestureRecognizer extends OneSequenceGestureRecognizer {
-  _AndroidViewGestureRecognizer(this.dispatcher, List<OneSequenceGestureRecognizer> gestureRecognizers) {
-    this.gestureRecognizers = gestureRecognizers;
-  }
-
-  final _MotionEventsDispatcher dispatcher;
-
-  // Maps a pointer to a list of its cached pointer events.
-  // Before the arena for a pointer is resolved all events are cached here, if we win the arena
-  // the cached events are dispatched to the view, if we lose the arena we clear the cache for
-  // the pointer.
-  final Map<int, List<PointerEvent>> cachedEvents = <int, List<PointerEvent>> {};
-
-  // Pointer for which we have already won the arena, events for pointers in this set are
-  // immediately dispatched to the Android view.
-  final Set<int> forwardedPointers = new Set<int>();
-
-  // We use OneSequenceGestureRecognizers as they support gesture arena teams.
-  // TODO(amirh): get a list of GestureRecognizers here.
-  // https://github.com/flutter/flutter/issues/20953
-  List<OneSequenceGestureRecognizer> _gestureRecognizers;
-  set gestureRecognizers(List<OneSequenceGestureRecognizer> recognizers) {
-    _gestureRecognizers = recognizers;
-    team = new GestureArenaTeam();
-    team.captain = this;
-    for (OneSequenceGestureRecognizer recognizer in _gestureRecognizers) {
-      recognizer.team = team;
-    }
-  }
-
-  @override
-  void addPointer(PointerDownEvent event) {
-    startTrackingPointer(event.pointer);
-    for (OneSequenceGestureRecognizer recognizer in _gestureRecognizers) {
-      recognizer.addPointer(event);
-    }
-  }
-
-  @override
-  String get debugDescription => 'Android view';
-
-  @override
-  void didStopTrackingLastPointer(int pointer) {
-    resolve(GestureDisposition.rejected);
-  }
-
-  @override
-  void handleEvent(PointerEvent event) {
-    if (!forwardedPointers.contains(event.pointer)) {
-      cacheEvent(event);
-    } else {
-      dispatcher.handlePointerEvent(event);
-    }
-    stopTrackingIfPointerNoLongerDown(event);
-  }
-
-  @override
-  void acceptGesture(int pointer) {
-    flushPointerCache(pointer);
-    forwardedPointers.add(pointer);
-  }
-
-  @override
-  void rejectGesture(int pointer) {
-    stopTrackingPointer(pointer);
-    cachedEvents.remove(pointer);
-  }
-
-  void cacheEvent(PointerEvent event) {
-    if (!cachedEvents.containsKey(event.pointer)) {
-      cachedEvents[event.pointer] = <PointerEvent> [];
-    }
-    cachedEvents[event.pointer].add(event);
-  }
-
-  void flushPointerCache(int pointer) {
-    cachedEvents.remove(pointer)?.forEach(dispatcher.handlePointerEvent);
-  }
-
-  @override
-  void stopTrackingPointer(int pointer) {
-    super.stopTrackingPointer(pointer);
-    forwardedPointers.remove(pointer);
-  }
-
-  void reset() {
-    forwardedPointers.forEach(super.stopTrackingPointer);
-    forwardedPointers.clear();
-    cachedEvents.keys.forEach(super.stopTrackingPointer);
-    cachedEvents.clear();
-    resolve(GestureDisposition.rejected);
+    _motionEventsDispatcher.handlePointerEvent(event);
   }
 }
 

packages/flutter/lib/src/widgets/platform_view.dart

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:flutter/foundation.dart';
-import 'package:flutter/gestures.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 
@@ -22,12 +21,6 @@ import 'framework.dart';
 /// The widget fill all available space, the parent of this object must provide bounded layout
 /// constraints.
 ///
-/// AndroidView participates in Flutter's [GestureArena]s, and dispatches touch events to the
-/// Android view iff it won the arena. Specific gestures that should be dispatched to the Android
-/// view can be specified in [AndroidView.gestureRecognizers]. If
-/// [AndroidView.gestureRecognizers] is empty, the gesture will be dispatched to the Android
-/// view iff it was not claimed by any other gesture recognizer.
-///
 /// The Android view object is created using a [PlatformViewFactory](/javadoc/io/flutter/plugin/platform/PlatformViewFactory.html).
 /// Plugins can register platform view factories with [PlatformViewRegistry#registerViewFactory](/javadoc/io/flutter/plugin/platform/PlatformViewRegistry.html#registerViewFactory-java.lang.String-io.flutter.plugin.platform.PlatformViewFactory-).
 ///
@@ -48,7 +41,7 @@ import 'framework.dart';
 class AndroidView extends StatefulWidget {
   /// Creates a widget that embeds an Android view.
   ///
-  /// The `viewType`, `hitTestBehavior`, and `gestureRecognizers` parameters must not be null.
+  /// The `viewType` and `hitTestBehavior` parameters must not be null.
   /// If `creationParams` is not null then `creationParamsCodec` must not be null.
   AndroidView({
     Key key,
@@ -56,12 +49,10 @@ class AndroidView extends StatefulWidget {
     this.onPlatformViewCreated,
     this.hitTestBehavior = PlatformViewHitTestBehavior.opaque,
     this.layoutDirection,
-    this.gestureRecognizers = const <OneSequenceGestureRecognizer> [],
     this.creationParams,
     this.creationParamsCodec
   }) : assert(viewType != null),
        assert(hitTestBehavior != null),
-        assert(gestureRecognizers != null),
        assert(creationParams == null || creationParamsCodec != null),
        super(key: key);
 
@@ -87,17 +78,6 @@ class AndroidView extends StatefulWidget {
   /// If this is null, the ambient [Directionality] is used instead.
   final TextDirection layoutDirection;
 
-  /// Which gestures should be forwarded to the Android view.
-  ///
-  /// The gesture recognizers on this list participate in the gesture arena for each pointer
-  /// that was put down on the widget. If any of the recognizers on this list wins the
-  /// gesture arena, the entire pointer event sequence starting from the pointer down event
-  /// will be dispatched to the Android view.
-  // We use OneSequenceGestureRecognizers as they support gesture arena teams.
-  // TODO(amirh): get a list of GestureRecognizers here.
-  // https://github.com/flutter/flutter/issues/20953
-  final List<OneSequenceGestureRecognizer> gestureRecognizers;
-
   /// Passed as the args argument of [PlatformViewFactory#create](/javadoc/io/flutter/plugin/platform/PlatformViewFactory.html#create-android.content.Context-int-java.lang.Object-)
   ///
   /// This can be used by plugins to pass constructor parameters to the embedded Android view.
@@ -125,8 +105,7 @@ class _AndroidViewState extends State<AndroidView> {
   Widget build(BuildContext context) {
     return new _AndroidPlatformView(
         controller: _controller,
-        hitTestBehavior: widget.hitTestBehavior,
-        gestureRecognizers: widget.gestureRecognizers,
+        hitTestBehavior: widget.hitTestBehavior
     );
   }
 
@@ -203,28 +182,20 @@ class _AndroidPlatformView extends LeafRenderObjectWidget {
     Key key,
     @required this.controller,
     @required this.hitTestBehavior,
-    @required this.gestureRecognizers,
   }) : assert(controller != null),
        assert(hitTestBehavior != null),
-       assert(gestureRecognizers != null),
        super(key: key);
 
   final AndroidViewController controller;
   final PlatformViewHitTestBehavior hitTestBehavior;
-  final List<OneSequenceGestureRecognizer> gestureRecognizers;
 
   @override
   RenderObject createRenderObject(BuildContext context) =>
-      new RenderAndroidView(
-        viewController: controller,
-        hitTestBehavior: hitTestBehavior,
-        gestureRecognizers: gestureRecognizers,
-      );
+    new RenderAndroidView(viewController: controller, hitTestBehavior: hitTestBehavior);
 
   @override
   void updateRenderObject(BuildContext context, RenderAndroidView renderObject) {
     renderObject.viewController = controller;
     renderObject.hitTestBehavior = hitTestBehavior;
-    renderObject.gestureRecognizers = gestureRecognizers;
   }
 }

packages/flutter/test/widgets/platform_view_test.dart

@@ -513,75 +513,4 @@ void main() {
       ]),
     );
   });
-
-  testWidgets('Android view can lose gesture arenas', (WidgetTester tester) async {
-    final int currentViewId = platformViewsRegistry.getNextPlatformViewId();
-    final FakePlatformViewsController viewsController = new FakePlatformViewsController(TargetPlatform.android);
-    viewsController.registerViewType('webview');
-    bool verticalDragAcceptedByParent = false;
-    await tester.pumpWidget(
-      new Align(
-        alignment: Alignment.topLeft,
-        child: new Container(
-          margin: const EdgeInsets.all(10.0),
-          child: GestureDetector(
-            onVerticalDragStart: (DragStartDetails d) { verticalDragAcceptedByParent = true; },
-            child: SizedBox(
-              width: 200.0,
-              height: 100.0,
-              child: AndroidView(viewType: 'webview', layoutDirection: TextDirection.ltr),
-            ),
-          ),
-        ),
-      ),
-    );
-
-    final TestGesture gesture = await tester.startGesture(const Offset(50.0, 50.0));
-    await gesture.moveBy(const Offset(0.0, 100.0));
-    await gesture.up();
-
-    expect(verticalDragAcceptedByParent, true);
-    expect(
-      viewsController.motionEvents[currentViewId + 1],
-      isNull,
-    );
-  });
-
-  testWidgets('Android view gesture recognizers', (WidgetTester tester) async {
-    final int currentViewId = platformViewsRegistry.getNextPlatformViewId();
-    final FakePlatformViewsController viewsController = new FakePlatformViewsController(TargetPlatform.android);
-    viewsController.registerViewType('webview');
-    bool verticalDragAcceptedByParent = false;
-    await tester.pumpWidget(
-      new Align(
-        alignment: Alignment.topLeft,
-        child: GestureDetector(
-          onVerticalDragStart: (DragStartDetails d) { verticalDragAcceptedByParent = true; },
-          child: SizedBox(
-            width: 200.0,
-            height: 100.0,
-            child: AndroidView(
-              viewType: 'webview',
-              gestureRecognizers: <OneSequenceGestureRecognizer> [new VerticalDragGestureRecognizer()],
-              layoutDirection: TextDirection.ltr,
-            ),
-          ),
-        ),
-      ),
-    );
-
-    final TestGesture gesture = await tester.startGesture(const Offset(50.0, 50.0));
-    await gesture.moveBy(const Offset(0.0, 100.0));
-    await gesture.up();
-
-    expect(verticalDragAcceptedByParent, false);
-    expect(
-      viewsController.motionEvents[currentViewId + 1],
-      orderedEquals(<FakeMotionEvent> [
-        const FakeMotionEvent(AndroidViewController.kActionDown, <int> [0], <Offset> [Offset(50.0, 50.0)]),
-        const FakeMotionEvent(AndroidViewController.kActionMove, <int> [0], <Offset> [Offset(50.0, 150.0)]),
-        const FakeMotionEvent(AndroidViewController.kActionUp, <int> [0], <Offset> [Offset(50.0, 150.0)]),
-      ]),
-    );
-  });
 }