[android] enqueue platform views for deletion.

shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java

@@ -118,6 +118,9 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
   // Map of unique IDs to views that render overlay layers.
   private final SparseArray<PlatformOverlayView> overlayLayerViews;
 
+  // Platform views to be disposed on the next frame.
+  private ArrayList<Integer> platformViewsToDispose;
+
   // The platform view wrappers that are appended to FlutterView.
   //
   // These platform views use a TextureLayer in the framework. This is different than
@@ -239,6 +242,15 @@ public void dispose(int viewId) {
             Log.e(TAG, "Disposing unknown platform view with id: " + viewId);
             return;
           }
+
+          // The platform view is displayed using a PlatformViewLayer. Enqueue
+          // the platform view for deletion during the next frame.
+          final FlutterMutatorView parentView = platformViewParent.get(viewId);
+          if (parentView != null) {
+            platformViewsToDispose.add(viewId);
+            return;
+          }
+
           if (platformView.getView() != null) {
             final View embeddedView = platformView.getView();
             final ViewGroup pvParent = (ViewGroup) embeddedView.getParent();
@@ -280,18 +292,6 @@ public void dispose(int viewId) {
             viewWrappers.remove(viewId);
             return;
           }
-          // The platform view is displayed using a PlatformViewLayer.
-          final FlutterMutatorView parentView = platformViewParent.get(viewId);
-          if (parentView != null) {
-            parentView.removeAllViews();
-            parentView.unsetOnDescendantFocusChangeListener();
-
-            final ViewGroup mutatorViewParent = (ViewGroup) parentView.getParent();
-            if (mutatorViewParent != null) {
-              mutatorViewParent.removeView(parentView);
-            }
-            platformViewParent.remove(viewId);
-          }
         }
 
         @Override
@@ -744,6 +744,7 @@ public PlatformViewsController() {
     viewWrappers = new SparseArray<>();
     platformViews = new SparseArray<>();
     platformViewParent = new SparseArray<>();
+    platformViewsToDispose = new ArrayList<>();
 
     motionEventTracker = MotionEventTracker.getInstance();
   }
@@ -1071,6 +1072,10 @@ private void diposeAllViews() {
       // Dispose deletes the entry from platformViews and clears associated resources.
       channelHandler.dispose(viewId);
     }
+    for (Integer viewId : platformViewsToDispose) {
+      disposeHybridCompositionPlatformView(viewId);
+    }
+    platformViewsToDispose.clear();
   }
 
   // Invoked when the Android system is requesting we reduce memory usage.
@@ -1247,6 +1252,19 @@ public void onBeginFrame() {
    * <p>This member is not intended for public use, and is only visible for testing.
    */
   public void onEndFrame() {
+    ArrayList<Integer> nextPlatformViewsToDispose = new ArrayList<>();
+    for (Integer viewId : platformViewsToDispose) {
+      // Any platform views that are queued for disposal but still in the composition
+      // tree must survive at least one more frame, but otherwise can be deleted.
+      if (currentFrameUsedPlatformViewIds.contains(viewId)) {
+        nextPlatformViewsToDispose.add(viewId);
+        continue;
+      }
+
+      disposeHybridCompositionPlatformView(viewId);
+    }
+    platformViewsToDispose = nextPlatformViewsToDispose;
+
     // If there are no platform views in the current frame,
     // then revert the image view surface and use the previous surface.
     //
@@ -1388,4 +1406,38 @@ private void removeOverlaySurfaces() {
   public SparseArray<PlatformOverlayView> getOverlayLayerViews() {
     return overlayLayerViews;
   }
+
+  private void disposeHybridCompositionPlatformView(int viewId) {
+    final PlatformView platformView = platformViews.get(viewId);
+    if (platformView != null) {
+      if (platformView.getView() != null) {
+        final View embeddedView = platformView.getView();
+        final ViewGroup pvParent = (ViewGroup) embeddedView.getParent();
+        if (pvParent != null) {
+          // Eagerly remove the embedded view from the PlatformViewWrapper.
+          // Without this call, we see some crashes because removing the view
+          // is used as a signal to stop processing.
+          pvParent.removeView(embeddedView);
+        }
+      }
+      platformViews.remove(viewId);
+      try {
+        platformView.dispose();
+      } catch (RuntimeException exception) {
+        Log.e(TAG, "Disposing platform view threw an exception", exception);
+      }
+    }
+
+    final FlutterMutatorView parentView = platformViewParent.get(viewId);
+    if (parentView != null) {
+      parentView.removeAllViews();
+      parentView.unsetOnDescendantFocusChangeListener();
+
+      final ViewGroup mutatorViewParent = (ViewGroup) parentView.getParent();
+      if (mutatorViewParent != null) {
+        mutatorViewParent.removeView(parentView);
+      }
+      platformViewParent.remove(viewId);
+    }
+  }
 }

shell/platform/android/test/io/flutter/plugin/platform/PlatformViewsControllerTest.java

@@ -908,6 +908,10 @@ public void disposeAndroidView_hybridComposition() {
 
     // Simulate dispose call from the framework.
     disposePlatformView(jni, platformViewsController, platformViewId);
+    assertNotNull(androidView.getParent());
+
+    // pump frame to force disposal.
+    platformViewsController.onEndFrame();
     assertNull(androidView.getParent());
 
     // Simulate create call from the framework.
@@ -947,6 +951,9 @@ public void disposeNullAndroidView() {
 
     // Simulate dispose call from the framework.
     disposePlatformView(jni, platformViewsController, platformViewId);
+    // pump frame to force disposal.
+    platformViewsController.onEndFrame();
+
     verify(platformView, times(1)).dispose();
   }
 
@@ -1090,6 +1097,9 @@ public void onEndFrame_removesPlatformViewParent() {
 
     // Simulate dispose call from the framework.
     disposePlatformView(jni, platformViewsController, platformViewId);
+    platformViewsController.onBeginFrame();
+    platformViewsController.onEndFrame();
+
     assertEquals(flutterView.getChildCount(), 1);
   }