fix(android): Always remove FirstDrawDoneListener after the first draw (#6152)

* fix(android): Always remove FirstDrawDoneListener after the first draw

The listener was removed from an OnGlobalLayoutListener, which only runs if
a layout pass follows the draw. On a static screen it stayed registered and
ran on every frame, retaining its callback. Post the removal to the main
thread instead so it always happens.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

* changelog

---------

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: runningcode

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- Always remove the first-draw listener after the first frame, even if no layout pass follows it ([#6152](https://github.com/getsentry/sentry-java/pull/6152))
+
 ## 8.61.1
 
 ### Fixes

sentry-android-core/src/main/java/io/sentry/android/core/internal/util/FirstDrawDoneListener.java

@@ -109,17 +109,15 @@ public void onDraw() {
     if (view == null) {
       return;
     }
-    // OnDrawListeners cannot be removed within onDraw, so we remove it with a
-    // GlobalLayoutListener
-    view.getViewTreeObserver()
-        .addOnGlobalLayoutListener(
-            new ViewTreeObserver.OnGlobalLayoutListener() {
-              @Override
-              public void onGlobalLayout() {
-                view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
-                view.getViewTreeObserver().removeOnDrawListener(FirstDrawDoneListener.this);
-              }
-            });
+    // OnDrawListeners cannot be removed within onDraw. Posting the removal instead of waiting for
+    // the next global layout guarantees it happens, even if no layout pass follows the draw.
+    mainThreadHandler.post(
+        () -> {
+          final ViewTreeObserver observer = view.getViewTreeObserver();
+          if (observer.isAlive()) {
+            observer.removeOnDrawListener(this);
+          }
+        });
     mainThreadHandler.postAtFrontOfQueue(callback);
   }
 

sentry-android-core/src/test/java/io/sentry/android/core/internal/util/FirstDrawDoneListenerTest.kt

@@ -113,49 +113,14 @@ class FirstDrawDoneListenerTest {
   }
 
   @Test
-  fun `registerForNextDraw unregister itself after onDraw`() {
+  fun `registerForNextDraw unregisters itself after onDraw without a layout pass`() {
     val view = fixture.getSut()
     FirstDrawDoneListener.registerForNextDraw(view, {}, fixture.buildInfo)
     assertFalse(fixture.onDrawListeners.isEmpty())
 
-    // Does not remove OnDrawListener before onDraw, even if OnGlobalLayout is triggered
-    view.viewTreeObserver.dispatchOnGlobalLayout()
-    assertFalse(fixture.onDrawListeners.isEmpty())
-
-    // Removes OnDrawListener in the next OnGlobalLayout after onDraw
-    view.viewTreeObserver.dispatchOnDraw()
-    view.viewTreeObserver.dispatchOnGlobalLayout()
-    assertTrue(fixture.onDrawListeners.isEmpty())
-  }
-
-  @Test
-  fun `OnGlobalLayoutListener is removed after cleanup`() {
-    val view = fixture.getSut()
-
-    // Initialize mOnGlobalLayoutListeners via a dummy add/remove
-    val dummyGlobalListener = ViewTreeObserver.OnGlobalLayoutListener {}
-    view.viewTreeObserver.addOnGlobalLayoutListener(dummyGlobalListener)
-    view.viewTreeObserver.removeOnGlobalLayoutListener(dummyGlobalListener)
-
-    // CopyOnWriteArray wraps an internal ArrayList called mData
-    val copyOnWriteArray: Any = view.viewTreeObserver.getProperty("mOnGlobalLayoutListeners")
-    val mDataField = copyOnWriteArray.javaClass.getDeclaredField("mData")
-    mDataField.isAccessible = true
-
-    @Suppress("UNCHECKED_CAST")
-    fun globalLayoutListeners(): ArrayList<*> = mDataField.get(copyOnWriteArray) as ArrayList<*>
-
-    assertTrue(globalLayoutListeners().isEmpty())
-
-    FirstDrawDoneListener.registerForNextDraw(view, {}, fixture.buildInfo)
-
-    // onDraw registers a cleanup OnGlobalLayoutListener
     view.viewTreeObserver.dispatchOnDraw()
-    assertFalse(globalLayoutListeners().isEmpty())
+    Shadows.shadowOf(Looper.getMainLooper()).idle()
 
-    // onGlobalLayout fires the cleanup, which removes both the draw and layout listeners
-    view.viewTreeObserver.dispatchOnGlobalLayout()
-    assertTrue(globalLayoutListeners().isEmpty())
     assertTrue(fixture.onDrawListeners.isEmpty())
   }