Improve performance of platform views on Android

shell/common/rasterizer.cc

@@ -91,8 +91,7 @@ void Rasterizer::Teardown() {
   surface_.reset();
   last_layer_tree_.reset();
 
-  if (raster_thread_merger_.get() != nullptr &&
-      raster_thread_merger_.get()->IsMerged()) {
+  if (raster_thread_merger_ && raster_thread_merger_->IsMerged()) {
     FML_DCHECK(raster_thread_merger_->IsEnabled());
     raster_thread_merger_->UnMergeNowIfLastOne();
     raster_thread_merger_->SetMergeUnmergeCallback(nullptr);

shell/platform/android/external_view_embedder/external_view_embedder.cc

@@ -212,7 +212,7 @@ AndroidExternalViewEmbedder::CreateSurfaceIfNeeded(GrDirectContext* context,
 // |ExternalViewEmbedder|
 PostPrerollResult AndroidExternalViewEmbedder::PostPrerollAction(
     fml::RefPtr<fml::RasterThreadMerger> raster_thread_merger) {
-  if (!FrameHasPlatformLayers()) {
+  if (!FrameHasPlatformLayers() || !raster_thread_merger) {
     return PostPrerollResult::kSuccess;
   }
   if (!raster_thread_merger->IsMerged()) {
@@ -264,14 +264,12 @@ void AndroidExternalViewEmbedder::BeginFrame(
 
   // The surface size changed. Therefore, destroy existing surfaces as
   // the existing surfaces in the pool can't be recycled.
-  if (frame_size_ != frame_size && raster_thread_merger->IsOnPlatformThread()) {
+  if (frame_size_ != frame_size) {
     surface_pool_->DestroyLayers(jni_facade_);
   }
   surface_pool_->SetFrameSize(frame_size);
   // JNI method must be called on the platform thread.
-  if (raster_thread_merger->IsOnPlatformThread()) {
-    jni_facade_->FlutterViewBeginFrame();
-  }
+  jni_facade_->FlutterViewBeginFrame();
 
   frame_size_ = frame_size;
   device_pixel_ratio_ = device_pixel_ratio;
@@ -288,14 +286,12 @@ void AndroidExternalViewEmbedder::EndFrame(
     fml::RefPtr<fml::RasterThreadMerger> raster_thread_merger) {
   surface_pool_->RecycleLayers();
   // JNI method must be called on the platform thread.
-  if (raster_thread_merger->IsOnPlatformThread()) {
-    jni_facade_->FlutterViewEndFrame();
-  }
+  jni_facade_->FlutterViewEndFrame();
 }
 
 // |ExternalViewEmbedder|
 bool AndroidExternalViewEmbedder::SupportsDynamicThreadMerging() {
-  return true;
+  return false;
 }
 
 }  // namespace flutter

shell/platform/android/io/flutter/embedding/android/FlutterImageView.java

@@ -188,6 +188,9 @@ public boolean acquireLatestImage() {
     if (!isAttachedToFlutterRenderer) {
       return false;
     }
+    if (currentImage != null) {
+      return true;
+    }
     // 1. `acquireLatestImage()` may return null if no new image is available.
     // 2. There's no guarantee that `onDraw()` is called after `invalidate()`.
     // For example, the device may not produce new frames if it's in sleep mode

shell/platform/android/io/flutter/embedding/engine/FlutterJNI.java

@@ -11,6 +11,7 @@
 import android.graphics.ImageDecoder;
 import android.graphics.SurfaceTexture;
 import android.os.Build;
+import android.os.Handler;
 import android.os.Looper;
 import android.util.Size;
 import android.view.Surface;
@@ -1006,40 +1007,45 @@ private void onPreEngineRestart() {
   @SuppressWarnings("unused")
   @UiThread
   public void onDisplayOverlaySurface(int id, int x, int y, int width, int height) {
-    ensureRunningOnMainThread();
-    if (platformViewsController == null) {
-      throw new RuntimeException(
-          "platformViewsController must be set before attempting to position an overlay surface");
-    }
-    platformViewsController.onDisplayOverlaySurface(id, x, y, width, height);
+    runOnMainThread(
+        () -> {
+          if (platformViewsController == null) {
+            throw new RuntimeException(
+                "platformViewsController must be set before attempting to position an overlay surface");
+          }
+          platformViewsController.onDisplayOverlaySurface(id, x, y, width, height);
+        });
   }
 
   @SuppressWarnings("unused")
   @UiThread
   public void onBeginFrame() {
-    ensureRunningOnMainThread();
-    if (platformViewsController == null) {
-      throw new RuntimeException(
-          "platformViewsController must be set before attempting to begin the frame");
-    }
-    platformViewsController.onBeginFrame();
+    runOnMainThread(
+        () -> {
+          if (platformViewsController == null) {
+            throw new RuntimeException(
+                "platformViewsController must be set before attempting to begin the frame");
+          }
+          platformViewsController.onBeginFrame();
+        });
   }
 
   @SuppressWarnings("unused")
   @UiThread
   public void onEndFrame() {
-    ensureRunningOnMainThread();
-    if (platformViewsController == null) {
-      throw new RuntimeException(
-          "platformViewsController must be set before attempting to end the frame");
-    }
-    platformViewsController.onEndFrame();
+    runOnMainThread(
+        () -> {
+          if (platformViewsController == null) {
+            throw new RuntimeException(
+                "platformViewsController must be set before attempting to end the frame");
+          }
+          platformViewsController.onEndFrame();
+        });
   }
 
   @SuppressWarnings("unused")
   @UiThread
   public FlutterOverlaySurface createOverlaySurface() {
-    ensureRunningOnMainThread();
     if (platformViewsController == null) {
       throw new RuntimeException(
           "platformViewsController must be set before attempting to position an overlay surface");
@@ -1050,12 +1056,14 @@ public FlutterOverlaySurface createOverlaySurface() {
   @SuppressWarnings("unused")
   @UiThread
   public void destroyOverlaySurfaces() {
-    ensureRunningOnMainThread();
-    if (platformViewsController == null) {
-      throw new RuntimeException(
-          "platformViewsController must be set before attempting to destroy an overlay surface");
-    }
-    platformViewsController.destroyOverlaySurfaces();
+    runOnMainThread(
+        () -> {
+          if (platformViewsController == null) {
+            throw new RuntimeException(
+                "platformViewsController must be set before attempting to destroy an overlay surface");
+          }
+          platformViewsController.destroyOverlaySurfaces();
+        });
   }
   // ----- End Engine Lifecycle Support ----
 
@@ -1241,13 +1249,15 @@ public void onDisplayPlatformView(
       int viewWidth,
       int viewHeight,
       FlutterMutatorsStack mutatorsStack) {
-    ensureRunningOnMainThread();
-    if (platformViewsController == null) {
-      throw new RuntimeException(
-          "platformViewsController must be set before attempting to position a platform view");
-    }
-    platformViewsController.onDisplayPlatformView(
-        viewId, x, y, width, height, viewWidth, viewHeight, mutatorsStack);
+    runOnMainThread(
+        () -> {
+          if (platformViewsController == null) {
+            throw new RuntimeException(
+                "platformViewsController must be set before attempting to position a platform view");
+          }
+          platformViewsController.onDisplayPlatformView(
+              viewId, x, y, width, height, viewWidth, viewHeight, mutatorsStack);
+        });
   }
 
   // TODO(mattcarroll): determine if this is nonull or nullable
@@ -1285,6 +1295,15 @@ private void ensureRunningOnMainThread() {
     }
   }
 
+  private void runOnMainThread(Runnable fn) {
+    if (Looper.myLooper() == mainLooper) {
+      fn.run();
+      return;
+    }
+    final Handler handler = new Handler(mainLooper);
+    handler.post(fn);
+  }
+
   /**
    * Delegate responsible for creating and updating Android-side caches of Flutter's semantics tree
    * and custom accessibility actions.

shell/platform/android/io/flutter/embedding/engine/mutatorsstack/FlutterMutatorView.java

@@ -120,10 +120,16 @@ public void readyToDisplay(
     this.mutatorsStack = mutatorsStack;
     this.left = left;
     this.top = top;
-    FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(width, height);
-    layoutParams.leftMargin = left;
-    layoutParams.topMargin = top;
-    setLayoutParams(layoutParams);
+    final FrameLayout.LayoutParams currentLayout = (FrameLayout.LayoutParams) getLayoutParams();
+    if (currentLayout.width != width
+        || currentLayout.height != height
+        || currentLayout.leftMargin != left
+        || currentLayout.topMargin != top) {
+      final FrameLayout.LayoutParams newLayoutParams = new FrameLayout.LayoutParams(width, height);
+      newLayoutParams.leftMargin = left;
+      newLayoutParams.topMargin = top;
+      setLayoutParams(newLayoutParams);
+    }
     setWillNotDraw(false);
   }
 

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

@@ -111,10 +111,23 @@ public class PlatformViewsController implements PlatformViewsAccessibilityDelega
   private boolean synchronizeToNativeViewHierarchy = true;
 
   // Overlay layer IDs that were displayed since the start of the current frame.
-  private HashSet<Integer> currentFrameUsedOverlayLayerIds;
+  private final HashSet<Integer> currentFrameUsedOverlayLayerIds;
 
   // Platform view IDs that were displayed since the start of the current frame.
-  private HashSet<Integer> currentFrameUsedPlatformViewIds;
+  private final HashSet<Integer> currentFrameUsedPlatformViewIds;
+
+  // The z-order of the views owned by controller that live in FlutterView.
+  // This is a stack that provides efficient querying of the views z-order.
+  private final SparseArray<View> viewZorder;
+
+  // The index of a view in viewZorder.
+  //
+  // This is used to determinate if the view is in the expected z-order.
+  // For example, if viewZorderIndex is 1, the view for index 1 in viewZorder must equal
+  // to the expected view in order to be considered in the correct order.
+  //
+  // This value is reset to 0 when the frame starts.
+  private int viewZorderIndex = 0;
 
   // Used to acquire the original motion events using the motionEventIds.
   private final MotionEventTracker motionEventTracker;
@@ -431,6 +444,7 @@ public PlatformViewsController() {
     overlayLayerViews = new SparseArray<>();
     currentFrameUsedOverlayLayerIds = new HashSet<>();
     currentFrameUsedPlatformViewIds = new HashSet<>();
+    viewZorder = new SparseArray<>();
 
     platformViews = new SparseArray<>();
     platformViewParent = new SparseArray<>();
@@ -502,6 +516,9 @@ public void attachToView(@NonNull View flutterView) {
    */
   public void detachFromView() {
     destroyOverlaySurfaces();
+    destroyHybridPlatformViews();
+    viewZorder.clear();
+
     this.flutterView = null;
     flutterViewConvertedToImageView = false;
 
@@ -716,6 +733,10 @@ private void flushAllViews() {
     if (contextToPlatformView.size() > 0) {
       contextToPlatformView.clear();
     }
+
+    destroyOverlaySurfaces();
+    destroyHybridPlatformViews();
+    viewZorder.clear();
   }
 
   private void initializeRootImageViewIfNeeded() {
@@ -798,15 +819,21 @@ public void onDisplayPlatformView(
 
     final FlutterMutatorView parentView = platformViewParent.get(viewId);
     parentView.readyToDisplay(mutatorsStack, x, y, width, height);
+
     parentView.setVisibility(View.VISIBLE);
-    parentView.bringToFront();
+    bringViewToFrontIfNeeded(parentView);
 
-    final FrameLayout.LayoutParams layoutParams =
-        new FrameLayout.LayoutParams(viewWidth, viewHeight);
     final View view = platformViews.get(viewId).getView();
     if (view != null) {
-      view.setLayoutParams(layoutParams);
-      view.bringToFront();
+      final ViewGroup.LayoutParams viewLayoutParams = view.getLayoutParams();
+      // setLayoutParams schedules a layout even when the params haven't changed.
+      // This is expensive on low end devices.
+      if (viewLayoutParams.width != viewWidth || viewLayoutParams.height != viewHeight) {
+        final FrameLayout.LayoutParams layoutParams =
+            new FrameLayout.LayoutParams(viewWidth, viewHeight);
+
+        view.setLayoutParams(layoutParams);
+      }
     }
     currentFrameUsedPlatformViewIds.add(viewId);
   }
@@ -832,20 +859,46 @@ public void onDisplayOverlaySurface(int id, int x, int y, int width, int height)
       ((FlutterView) flutterView).addView(overlayView);
     }
 
-    FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams((int) width, (int) height);
-    layoutParams.leftMargin = (int) x;
-    layoutParams.topMargin = (int) y;
-    overlayView.setLayoutParams(layoutParams);
+    // setLayoutParams schedules a layout even when the params haven't changed.
+    // This is expensive on low end devices.
+    final FrameLayout.LayoutParams currentParams =
+        (FrameLayout.LayoutParams) overlayView.getLayoutParams();
+    if (currentParams.width != width
+        || currentParams.height != height
+        || currentParams.leftMargin != x
+        || currentParams.topMargin != y) {
+      FrameLayout.LayoutParams layoutParams =
+          new FrameLayout.LayoutParams((int) width, (int) height);
+      layoutParams.leftMargin = (int) x;
+      layoutParams.topMargin = (int) y;
+      overlayView.setLayoutParams(layoutParams);
+    }
+
     overlayView.setVisibility(View.VISIBLE);
-    overlayView.bringToFront();
+    bringViewToFrontIfNeeded(overlayView);
     currentFrameUsedOverlayLayerIds.add(id);
   }
 
   public void onBeginFrame() {
+    viewZorderIndex = 0;
     currentFrameUsedOverlayLayerIds.clear();
     currentFrameUsedPlatformViewIds.clear();
   }
 
+  /** @param view The view that should be */
+  private void bringViewToFrontIfNeeded(View view) {
+    if (viewZorder.contains(viewZorderIndex) && viewZorder.get(viewZorderIndex) == view) {
+      viewZorderIndex++;
+      return;
+    }
+    // Remove the views from the current z-order index to the top of the stack.
+    viewZorder.removeAtRange(viewZorderIndex, viewZorder.size() - 1);
+    viewZorder.put(viewZorderIndex, view);
+    viewZorderIndex++;
+    io.flutter.Log.d("flutter", "->" + viewZorderIndex + "- view: " + view);
+    view.bringToFront();
+  }
+
   /**
    * Called by {@code FlutterJNI} when the Flutter frame was submitted.
    *
@@ -966,17 +1019,30 @@ public FlutterOverlaySurface createOverlaySurface() {
    *
    * <p>This method is used only internally by {@code FlutterJNI}.
    *
-   * <p>This member is not intended for public use, and is only visible for testing.
+   * <p>This member is not intended for public use.
    */
   public void destroyOverlaySurfaces() {
     for (int i = 0; i < overlayLayerViews.size(); i++) {
-      int overlayId = overlayLayerViews.keyAt(i);
-      FlutterImageView overlayView = overlayLayerViews.valueAt(i);
+      final int overlayId = overlayLayerViews.keyAt(i);
+      final FlutterImageView overlayView = overlayLayerViews.valueAt(i);
       overlayView.detachFromRenderer();
       if (flutterView != null) {
         ((FlutterView) flutterView).removeView(overlayView);
       }
     }
     overlayLayerViews.clear();
   }
+
+  /** Destroys the platform views that use hybrid composition. */
+  @VisibleForTesting
+  public void destroyHybridPlatformViews() {
+    for (int i = 0; i < platformViewParent.size(); i++) {
+      final int overlayId = platformViewParent.keyAt(i);
+      final FlutterMutatorView view = platformViewParent.valueAt(i);
+      if (flutterView != null) {
+        ((FlutterView) flutterView).removeView(view);
+      }
+    }
+    platformViewParent.clear();
+  }
 }