PlatformView Scroll Jank Sample (Add-to-App)

Minimal Add-to-App Flutter sample that reproduces Android PlatformView scroll jank with merged platform/UI threads (TLHC mode).

Since PR #174408 removed the opt-out flag for disabling merged platform/UI threads, merged threads are now always enabled. During scroll, setOffset() appears to trigger setLayoutParams() → requestLayout() → draw() serially within Choreographer#doFrame, which can lead to jank when multiple PlatformViews are present.

How to run

flutter run --profile

1. App launches with a native Android screen
2. Tap "Open Flutter PlatformView Test" to open the Flutter view
3. Scroll the list up and down — frame drops should be visible

What this reproduces

A ListView with 8 AndroidView PlatformViews (simulating ad banners) interleaved with regular Flutter widgets. Scrolling appears to cause jank because setOffset() triggers setLayoutParams() → requestLayout() → draw() for every visible PlatformView on every frame.

Structure

lib/
  main.dart                   — ListView with 8 AndroidView + regular Flutter cards

android/.../
  NativeMainActivity.kt       — Native Android launcher screen
  activity_native_main.xml    — "Open Flutter PlatformView Test" button
  MainActivity.kt             — FlutterActivity, registers PlatformView factory
  AndroidTextViewFactory.kt   — PlatformViewFactory implementation
  AndroidTextView.kt          — Native view (ImageView + TextView, simulating ad banner)

Environment

• Flutter 3.38+ (platform/UI thread merge opt-out removed)
• Android physical device
• PlatformView mode: TLHC (Texture Layer Hybrid Composition)
• Reproducible with both Impeller and Skia