Fixed flicker when docking task from recents.

Regression introduced by ag/1044640 where we don't want recents to the
visible if it's stack isn't fullscreen or focused. However, it is
possible for switching the home stack to not-fullscreen to prolonged
while transitioning to split-screen mode from recents. We now check
for if the docked stack exists which is a better indicator we are in
split-screen mode regardless of if the stask is fullscreen.

Bug: 28882948
Bug: 28246419
Change-Id: I54c02cc1486e7b5bf6a20dd0706c9bfe3f40a953

1 files changed, 9 insertions, 7 deletions

diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index 3811b616a7f2..9718ae86d42e 100644
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -1819,22 +1819,24 @@ final class ActivityStack {
     private boolean shouldBeVisible(ActivityRecord r, boolean behindTranslucentActivity,
             boolean stackVisibleBehind, ActivityRecord visibleBehind,
             boolean behindFullscreenActivity) {
-        // mLaunchingBehind: Activities launching behind are at the back of the task stack
-        // but must be drawn initially for the animation as though they were visible.
-        final boolean activityVisibleBehind =
-                (behindTranslucentActivity || stackVisibleBehind) && visibleBehind == r;
 
         if (!okToShowLocked(r)) {
             return false;
         }
 
+        // mLaunchingBehind: Activities launching behind are at the back of the task stack
+        // but must be drawn initially for the animation as though they were visible.
+        final boolean activityVisibleBehind =
+                (behindTranslucentActivity || stackVisibleBehind) && visibleBehind == r;
+
         boolean isVisible =
                 !behindFullscreenActivity || r.mLaunchTaskBehind || activityVisibleBehind;
 
         if (isVisible && r.isRecentsActivity()) {
-            // Recents activity can only be visible if the home stack isn't fullscreen or is the
-            // focused stack.
-            isVisible = !mFullscreen || mStackSupervisor.isFocusedStack(this);
+            // Recents activity can only be visible if the home stack is the focused stack or we are
+            // in split-screen mode.
+            isVisible = mStackSupervisor.getStack(DOCKED_STACK_ID) != null
+                    || mStackSupervisor.isFocusedStack(this);
         }
 
         return isVisible;