Add tests for platform views' hover behavior (flutter#61667)

Author: dkwingsmt

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

@@ -12,6 +12,7 @@ import 'package:flutter/gestures.dart';
 import 'package:flutter/semantics.dart';
 import 'package:flutter/services.dart';
 
+import 'binding.dart';
 import 'box.dart';
 import 'layer.dart';
 import 'mouse_cursor.dart';
@@ -662,9 +663,15 @@ class PlatformViewRenderBox extends RenderBox with _PlatformViewGestureMixin {
 mixin _PlatformViewGestureMixin on RenderBox implements MouseTrackerAnnotation {
 
   /// How to behave during hit testing.
-  // The implicit setter is enough here as changing this value will just affect
-  // any newly arriving events there's nothing we need to invalidate.
-  PlatformViewHitTestBehavior hitTestBehavior;
+  // Changing _hitTestBehavior might affect which objects are considered hovered over.
+  set hitTestBehavior(PlatformViewHitTestBehavior value) {
+    if (value != _hitTestBehavior) {
+      _hitTestBehavior = value;
+      if (owner != null)
+        RendererBinding.instance.mouseTracker.schedulePostFrameCheck();
+    }
+  }
+  PlatformViewHitTestBehavior _hitTestBehavior;
 
   _HandlePointerEvent _handlePointerEvent;
 
@@ -690,15 +697,15 @@ mixin _PlatformViewGestureMixin on RenderBox implements MouseTrackerAnnotation {
 
   @override
   bool hitTest(BoxHitTestResult result, { Offset position }) {
-    if (hitTestBehavior == PlatformViewHitTestBehavior.transparent || !size.contains(position)) {
+    if (_hitTestBehavior == PlatformViewHitTestBehavior.transparent || !size.contains(position)) {
       return false;
     }
     result.add(BoxHitTestEntry(this, position));
-    return hitTestBehavior == PlatformViewHitTestBehavior.opaque;
+    return _hitTestBehavior == PlatformViewHitTestBehavior.opaque;
   }
 
   @override
-  bool hitTestSelf(Offset position) => hitTestBehavior != PlatformViewHitTestBehavior.transparent;
+  bool hitTestSelf(Offset position) => _hitTestBehavior != PlatformViewHitTestBehavior.transparent;
 
   @override
   PointerEnterEventListener get onEnter => null;

packages/flutter/test/rendering/platform_view_test.dart

@@ -19,6 +19,7 @@ void main() {
     FakePlatformViewController fakePlatformViewController;
     PlatformViewRenderBox platformViewRenderBox;
     setUp(() {
+      renderer; // Initialize bindings
       fakePlatformViewController = FakePlatformViewController(0);
       platformViewRenderBox = PlatformViewRenderBox(
         controller: fakePlatformViewController,

packages/flutter/test/widgets/platform_view_test.dart

@@ -2433,4 +2433,144 @@ void main() {
       expect(controller.focusCleared, true);
     });
   });
+
+  testWidgets('Platform views respect hitTestBehavior', (WidgetTester tester) async {
+    final FakePlatformViewController controller = FakePlatformViewController(0);
+
+    final List<String> logs = <String>[];
+
+    // -------------------------
+    // | MouseRegion1          |       MouseRegion1
+    // |  |-----------------|  |        |
+    // |  | MouseRegion2    |  |        |- Stack
+    // |  |   |---------|   |  |            |
+    // |  |   |Platform |   |  |            |- MouseRegion2
+    // |  |   |View     |   |  |            |- PlatformView
+    // |  |   |---------|   |  |
+    // |  |                 |  |
+    // |  |-----------------|  |
+    // |                       |
+    // -------------------------
+    Widget scaffold(Widget target) {
+      return Directionality(
+        textDirection: TextDirection.ltr,
+        child: Center(
+          child: SizedBox(
+            width: 600,
+            height: 600,
+            child: MouseRegion(
+              onEnter: (_) { logs.add('enter1'); },
+              onExit: (_) { logs.add('exit1'); },
+              cursor: SystemMouseCursors.forbidden,
+              child: Stack(
+                children: <Widget>[
+                  Center(
+                    child: SizedBox(
+                      width: 400,
+                      height: 400,
+                      child: MouseRegion(
+                        onEnter: (_) { logs.add('enter2'); },
+                        onExit: (_) { logs.add('exit2'); },
+                        cursor: SystemMouseCursors.text,
+                      ),
+                    ),
+                  ),
+                  Center(
+                    child: SizedBox(
+                      width: 200,
+                      height: 200,
+                      child: target,
+                    ),
+                  ),
+                ],
+              )
+            ),
+          ),
+        ),
+      );
+    }
+
+    final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse, pointer: 0);
+    addTearDown(gesture.removePointer);
+
+    // Test: Opaque
+    await tester.pumpWidget(
+      scaffold(PlatformViewSurface(
+        controller: controller,
+        hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+        gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{}
+      ))
+    );
+    logs.clear();
+
+    await gesture.moveTo(const Offset(400, 300));
+    expect(logs, <String>['enter1']);
+    expect(controller.dispatchedPointerEvents, hasLength(1));
+    expect(controller.dispatchedPointerEvents[0].runtimeType, PointerHoverEvent);
+    logs.clear();
+    controller.dispatchedPointerEvents.clear();
+
+    // Test: changing no option does not trigger events
+    await tester.pumpWidget(
+      scaffold(PlatformViewSurface(
+        controller: controller,
+        hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+        gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{}
+      ))
+    );
+    expect(logs, isEmpty);
+    expect(controller.dispatchedPointerEvents, isEmpty);
+
+    // Test: Transluscent
+    await tester.pumpWidget(
+      scaffold(PlatformViewSurface(
+        controller: controller,
+        hitTestBehavior: PlatformViewHitTestBehavior.translucent,
+        gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{}
+      ))
+    );
+    expect(logs, <String>['enter2']);
+    expect(controller.dispatchedPointerEvents, isEmpty);
+    logs.clear();
+
+    await gesture.moveBy(const Offset(1, 1));
+    expect(logs, isEmpty);
+    expect(controller.dispatchedPointerEvents, hasLength(1));
+    expect(controller.dispatchedPointerEvents[0].runtimeType, PointerHoverEvent);
+    expect(controller.dispatchedPointerEvents[0].position, const Offset(401, 301));
+    expect(controller.dispatchedPointerEvents[0].localPosition, const Offset(101, 101));
+    controller.dispatchedPointerEvents.clear();
+
+    // Test: Transparent
+    await tester.pumpWidget(
+      scaffold(PlatformViewSurface(
+        controller: controller,
+        hitTestBehavior: PlatformViewHitTestBehavior.transparent,
+        gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{}
+      ))
+    );
+    expect(logs, isEmpty);
+    expect(controller.dispatchedPointerEvents, isEmpty);
+
+    await gesture.moveBy(const Offset(1, 1));
+    expect(logs, isEmpty);
+    expect(controller.dispatchedPointerEvents, isEmpty);
+
+    // Test: Back to opaque
+    await tester.pumpWidget(
+      scaffold(PlatformViewSurface(
+        controller: controller,
+        hitTestBehavior: PlatformViewHitTestBehavior.opaque,
+        gestureRecognizers: const <Factory<OneSequenceGestureRecognizer>>{}
+      ))
+    );
+    expect(logs, <String>['exit2']);
+    expect(controller.dispatchedPointerEvents, isEmpty);
+    logs.clear();
+
+    await gesture.moveBy(const Offset(1, 1));
+    expect(logs, isEmpty);
+    expect(controller.dispatchedPointerEvents, hasLength(1));
+    expect(controller.dispatchedPointerEvents[0].runtimeType, PointerHoverEvent);
+  });
 }