From 215ff2e7feab950286cf1dfc5159db7331b8fa74 Mon Sep 17 00:00:00 2001 From: Gray Mackall <34871572+gmackall@users.noreply.github.com> Date: Thu, 15 Jan 2026 18:30:12 -0800 Subject: [PATCH] Fix hcpp flicker when scrolling off/on screen (#181009) Don't apply the transaction immediately, but let it be applied with flutter frame timing. Fixes https://github.com/flutter/flutter/issues/175547 See videos:
With Change Without Change
## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [ ] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). 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[Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md --------- Co-authored-by: Gray Mackall --- .../external_view_embedder_2.cc | 6 +-- .../platform/PlatformViewsController2.java | 6 +-- .../PlatformViewsController2Test.java | 47 +++++++++++++++++++ 3 files changed, 52 insertions(+), 7 deletions(-) diff --git a/engine/src/flutter/shell/platform/android/external_view_embedder/external_view_embedder_2.cc b/engine/src/flutter/shell/platform/android/external_view_embedder/external_view_embedder_2.cc index d1a7d19ebca..defcd11467d 100644 --- a/engine/src/flutter/shell/platform/android/external_view_embedder/external_view_embedder_2.cc +++ b/engine/src/flutter/shell/platform/android/external_view_embedder/external_view_embedder_2.cc @@ -83,7 +83,8 @@ void AndroidExternalViewEmbedder2::SubmitFlutterView( jni_facade->hidePlatformView2(view_id); } - jni_facade->applyTransaction(); + jni_facade->swapTransaction(); + jni_facade->onEndFrame2(); })); views_visible_last_frame_.clear(); return; @@ -170,13 +171,12 @@ void AndroidExternalViewEmbedder2::SubmitFlutterView( slices = std::move(slices_), views_visible_last_frame = views_visible_last_frame_, overlay_layer_has_content_this_frame_]() mutable -> void { - jni_facade->swapTransaction(); - if (overlay_layer_has_content_this_frame_) { ShowOverlayLayerIfNeeded(); } else { HideOverlayLayerIfNeeded(); } + jni_facade->swapTransaction(); for (int64_t view_id : composition_order) { DlRect view_rect = GetViewRect(view_id, view_params); diff --git a/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController2.java b/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController2.java index a5b4cbad9b7..cee347b0b1e 100644 --- a/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController2.java +++ b/engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/PlatformViewsController2.java @@ -608,9 +608,8 @@ public class PlatformViewsController2 implements PlatformViewsAccessibilityDeleg if (overlaySurfaceControl == null) { return; } - SurfaceControl.Transaction tx = new SurfaceControl.Transaction(); + SurfaceControl.Transaction tx = createTransaction(); tx.setVisibility(overlaySurfaceControl, /*visible=*/ true); - tx.apply(); } @RequiresApi(API_LEVELS.API_34) @@ -618,9 +617,8 @@ public class PlatformViewsController2 implements PlatformViewsAccessibilityDeleg if (overlaySurfaceControl == null) { return; } - SurfaceControl.Transaction tx = new SurfaceControl.Transaction(); + SurfaceControl.Transaction tx = createTransaction(); tx.setVisibility(overlaySurfaceControl, /*visible=*/ false); - tx.apply(); } public boolean isHcppEnabled() { diff --git a/engine/src/flutter/shell/platform/android/test/io/flutter/plugin/platform/PlatformViewsController2Test.java b/engine/src/flutter/shell/platform/android/test/io/flutter/plugin/platform/PlatformViewsController2Test.java index 3df7d5ee7e7..0b532a37dc2 100644 --- a/engine/src/flutter/shell/platform/android/test/io/flutter/plugin/platform/PlatformViewsController2Test.java +++ b/engine/src/flutter/shell/platform/android/test/io/flutter/plugin/platform/PlatformViewsController2Test.java @@ -14,8 +14,10 @@ import android.content.res.AssetManager; import android.graphics.SurfaceTexture; import android.media.Image; import android.util.SparseArray; +import android.view.AttachedSurfaceControl; import android.view.MotionEvent; import android.view.Surface; +import android.view.SurfaceControl; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; @@ -506,6 +508,51 @@ public class PlatformViewsController2Test { verify(platformView, times(1)).dispose(); } + // Class member variable + private SurfaceControl.Transaction mCapturedTx; + + @Test + @Config(shadows = {ShadowFlutterJNI.class, ShadowPlatformTaskQueue.class}) + public void showOverlaySurfaceDefersTransactionUntilEndFrame() { + + PlatformViewsController2 controller = + new PlatformViewsController2() { + @Override + public SurfaceControl.Transaction createTransaction() { + // Call super to ensure the real transaction is added to the private + // 'pendingTransactions' list + SurfaceControl.Transaction realTx = super.createTransaction(); + // Spy on it so we can verify calls like 'apply()' + mCapturedTx = spy(realTx); + return mCapturedTx; + } + }; + + PlatformViewRegistryImpl registry = new PlatformViewRegistryImpl(); + controller.setRegistry(registry); + + // Mocks + FlutterView mockFlutterView = mock(FlutterView.class); + AttachedSurfaceControl mockAttachedSurfaceControl = mock(AttachedSurfaceControl.class); + + when(mockFlutterView.getRootSurfaceControl()).thenReturn(mockAttachedSurfaceControl); + when(mockAttachedSurfaceControl.buildReparentTransaction(any())) + .thenReturn(new SurfaceControl.Transaction()); + + controller.attachToView(mockFlutterView); + controller.createOverlaySurface(); + + controller.showOverlaySurface(); + assertNotNull("Transaction should have been created", mCapturedTx); + verify(mCapturedTx, never()).apply(); + + controller.swapTransactions(); + controller.onEndFrame(); + + verify(mockAttachedSurfaceControl, times(1)) + .applyTransactionOnDraw(any(SurfaceControl.Transaction.class)); + } + private static ByteBuffer encodeMethodCall(MethodCall call) { final ByteBuffer buffer = StandardMethodCodec.INSTANCE.encodeMethodCall(call); buffer.rewind();