Only dispatch window visibility aggregation for targetSdk >= N
Some existing apps treat drawable visibility notifications as a signal
to crossfade from a placeholder to the new image for the purposes of
scrolling onscreen via a recycling collection view or similar. Since
dispatchVisibilityAggregated is now called for window visibility
changes and ImageView informs its drawable of the visiblity change,
the extra call triggers a repeat fade-in in some existing apps when
you return them to visibility.
These apps should pay attention to the second parameter of
Drawable#setVisible, which signals that animations should not restart
in response to a visibility change. Updating to targetSdkVersion=24+
will enable the new behavior.
Bug 30216207
Change-Id: I27ce9f09bc7544863f7f7980c273650949db21cc
diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 4dc1009..7494b94 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -52,6 +52,7 @@
import android.media.AudioManager;
import android.os.Binder;
import android.os.Build;
+import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.os.Debug;
import android.os.Handler;
@@ -1540,7 +1541,15 @@
if (viewVisibilityChanged) {
mAttachInfo.mWindowVisibility = viewVisibility;
host.dispatchWindowVisibilityChanged(viewVisibility);
- host.dispatchVisibilityAggregated(viewVisibility == View.VISIBLE);
+
+ // Prior to N we didn't have dispatchVisibilityAggregated to give a more accurate
+ // view into when views are visible to the user or not. ImageView never dealt with
+ // telling its drawable about window visibility, among other things. Some apps cause
+ // an additional crossfade animation when windows become visible if they get this
+ // additional call, so only send it to new apps to avoid new visual jank.
+ if (host.getContext().getApplicationInfo().targetSdkVersion >= VERSION_CODES.N) {
+ host.dispatchVisibilityAggregated(viewVisibility == View.VISIBLE);
+ }
if (viewVisibility != View.VISIBLE || mNewSurfaceNeeded) {
endDragResizing();
destroyHardwareResources();