Ensure no more callback invocations after onBackCancelled

When unregistering a back callback which is currently in-progress, onBackCancelled is dispatched. After dispatching onBackCancelled, it must be ensured that no more callback invocations to that same callback happen.

Bug: 351777537
Flag: com.android.window.flags.predictive_back_system_anims
Test: atest WindowOnBackInvokedDispatcherTest
Test: Manual, i.e. unregistering a callback during an active back gesture in a test app and verifying that after onBackCancelled no more onBackProgressed or other events are dispatched
Change-Id: I9a0b3a7c19e565070abc550cd02b520c693c443e

3 files changed, 10 insertions, 1 deletions

diff --git a/core/java/android/window/BackProgressAnimator.java b/core/java/android/window/BackProgressAnimator.java
index d28500c0a1ea..12d4ab8bc963 100644
--- a/core/java/android/window/BackProgressAnimator.java
+++ b/core/java/android/window/BackProgressAnimator.java
@@ -16,12 +16,15 @@
 
 package android.window;
 
+import static com.android.internal.annotations.VisibleForTesting.Visibility.PACKAGE;
+
 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.util.FloatProperty;
 import android.util.TimeUtils;
 import android.view.Choreographer;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.dynamicanimation.animation.DynamicAnimation;
 import com.android.internal.dynamicanimation.animation.FlingAnimation;
 import com.android.internal.dynamicanimation.animation.FloatValueHolder;
@@ -210,7 +213,8 @@ public class BackProgressAnimator implements DynamicAnimation.OnAnimationUpdateL
     }
 
     /** Returns true if the back animation is in progress. */
-    boolean isBackAnimationInProgress() {
+    @VisibleForTesting(visibility = PACKAGE)
+    public boolean isBackAnimationInProgress() {
         return mBackAnimationInProgress;
     }
 
diff --git a/core/java/android/window/WindowOnBackInvokedDispatcher.java b/core/java/android/window/WindowOnBackInvokedDispatcher.java
index 9b87e2351e3f..7bbc3dbb29db 100644
--- a/core/java/android/window/WindowOnBackInvokedDispatcher.java
+++ b/core/java/android/window/WindowOnBackInvokedDispatcher.java
@@ -244,6 +244,7 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
                 // We should call onBackCancelled() when an active callback is removed from
                 // dispatcher.
                 sendCancelledIfInProgress(callback);
+                mHandler.post(mProgressAnimator::reset);
                 setTopOnBackInvokedCallback(getTopCallback());
             }
         }
diff --git a/core/tests/coretests/src/android/window/WindowOnBackInvokedDispatcherTest.java b/core/tests/coretests/src/android/window/WindowOnBackInvokedDispatcherTest.java
index d4482f243939..9ae96a0fc9d8 100644
--- a/core/tests/coretests/src/android/window/WindowOnBackInvokedDispatcherTest.java
+++ b/core/tests/coretests/src/android/window/WindowOnBackInvokedDispatcherTest.java
@@ -348,12 +348,16 @@ public class WindowOnBackInvokedDispatcherTest {
 
         waitForIdle();
         verify(mCallback1).onBackStarted(any(BackEvent.class));
+        assertTrue(mDispatcher.mProgressAnimator.isBackAnimationInProgress());
 
         mDispatcher.unregisterOnBackInvokedCallback(mCallback1);
 
         waitForIdle();
         verify(mCallback1).onBackCancelled();
         verify(mWindowSession).setOnBackInvokedCallbackInfo(Mockito.eq(mWindow), isNull());
+        // Verify that ProgressAnimator is reset (and thus does not cause further callback event
+        // dispatching)
+        assertFalse(mDispatcher.mProgressAnimator.isBackAnimationInProgress());
     }
 
     @Test