Merge "Fix switching a background task into split screen unexpectedly" into tm-dev

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/SplitScreenController.java

@@ -414,6 +414,13 @@ public class SplitScreenController implements DragAndDropPolicy.Starter,
     }
 
     RemoteAnimationTarget[] onGoingToRecentsLegacy(RemoteAnimationTarget[] apps) {
+        if (isSplitScreenVisible()) {
+            // Evict child tasks except the top visible one under split root to ensure it could be
+            // launched as full screen when switching to it on recents.
+            final WindowContainerTransaction wct = new WindowContainerTransaction();
+            mStageCoordinator.prepareEvictInvisibleChildTasks(wct);
+            mSyncQueue.queue(wct);
+        }
         return reparentSplitTasksForAnimation(apps, true /*splitExpectedToBeVisible*/);
     }
 

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java

@@ -533,6 +533,11 @@ class StageCoordinator implements SplitLayout.SplitLayoutHandler,
         }
     }
 
+    void prepareEvictInvisibleChildTasks(WindowContainerTransaction wct) {
+        mMainStage.evictInvisibleChildren(wct);
+        mSideStage.evictInvisibleChildren(wct);
+    }
+
     Bundle resolveStartStage(@StageType int stage,
             @SplitPosition int position, @androidx.annotation.Nullable Bundle options,
             @androidx.annotation.Nullable WindowContainerTransaction wct) {

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageTaskListener.java

@@ -341,6 +341,15 @@ class StageTaskListener implements ShellTaskOrganizer.TaskListener {
         }
     }
 
+    void evictInvisibleChildren(WindowContainerTransaction wct) {
+        for (int i = mChildrenTaskInfo.size() - 1; i >= 0; i--) {
+            final ActivityManager.RunningTaskInfo taskInfo = mChildrenTaskInfo.valueAt(i);
+            if (!taskInfo.isVisible) {
+                wct.reparent(taskInfo.token, null /* parent */, false /* onTop */);
+            }
+        }
+    }
+
     void onSplitScreenListenerRegistered(SplitScreen.SplitScreenListener listener,
             @StageType int stage) {
         for (int i = mChildrenTaskInfo.size() - 1; i >= 0; --i) {