Remove old caption bar before adding a new one

When adding a new window caption, check if old one is present. If it is,
remove it before adding a new one.

Bug: 257121505
Test: manual, open a task in desktop mode, swipe to overview, click on
overview tile, task is again visible, resize task to check that only one
caption bar is shown

Change-Id: Ib4cc3934207f6d51a2ef101e4685285dd3f82743

libs/WindowManager/Shell/src/com/android/wm/shell/freeform/FreeformTaskTransitionObserver.java

@@ -98,9 +98,11 @@ public class FreeformTaskTransitionObserver implements Transitions.TransitionObs
 
             switch (change.getMode()) {
                 case WindowManager.TRANSIT_OPEN:
-                case WindowManager.TRANSIT_TO_FRONT:
                     onOpenTransitionReady(change, startT, finishT);
                     break;
+                case WindowManager.TRANSIT_TO_FRONT:
+                    onToFrontTransitionReady(change, startT, finishT);
+                    break;
                 case WindowManager.TRANSIT_CLOSE: {
                     taskInfoList.add(change.getTaskInfo());
                     onCloseTransitionReady(change, startT, finishT);
@@ -138,6 +140,21 @@ public class FreeformTaskTransitionObserver implements Transitions.TransitionObs
                 change.getTaskInfo(), startT, finishT);
     }
 
+    private void onToFrontTransitionReady(
+            TransitionInfo.Change change,
+            SurfaceControl.Transaction startT,
+            SurfaceControl.Transaction finishT) {
+        boolean exists = mWindowDecorViewModel.setupWindowDecorationForTransition(
+                change.getTaskInfo(),
+                startT,
+                finishT);
+        if (!exists) {
+            // Window caption does not exist, create it
+            mWindowDecorViewModel.createWindowDecoration(
+                    change.getTaskInfo(), change.getLeash(), startT, finishT);
+        }
+    }
+
     @Override
     public void onTransitionStarting(@NonNull IBinder transition) {}
 

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java

@@ -105,6 +105,11 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
         if (!shouldShowWindowDecor(taskInfo)) return false;
+        CaptionWindowDecoration oldDecoration = mWindowDecorByTaskId.get(taskInfo.taskId);
+        if (oldDecoration != null) {
+            // close the old decoration if it exists to avoid two window decorations being added
+            oldDecoration.close();
+        }
         final CaptionWindowDecoration windowDecoration = new CaptionWindowDecoration(
                 mContext,
                 mDisplayController,
@@ -141,23 +146,25 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel {
     }
 
     @Override
-    public void setupWindowDecorationForTransition(
+    public boolean setupWindowDecorationForTransition(
             RunningTaskInfo taskInfo,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT) {
         final CaptionWindowDecoration decoration = mWindowDecorByTaskId.get(taskInfo.taskId);
-        if (decoration == null) return;
+        if (decoration == null) return false;
 
         decoration.relayout(taskInfo, startT, finishT);
+        return true;
     }
 
     @Override
-    public void destroyWindowDecoration(RunningTaskInfo taskInfo) {
+    public boolean destroyWindowDecoration(RunningTaskInfo taskInfo) {
         final CaptionWindowDecoration decoration =
                 mWindowDecorByTaskId.removeReturnOld(taskInfo.taskId);
-        if (decoration == null) return;
+        if (decoration == null) return false;
 
         decoration.close();
+        return true;
     }
 
     private class CaptionTouchEventListener implements

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/WindowDecorViewModel.java

@@ -44,7 +44,7 @@ public interface WindowDecorViewModel {
      * @param taskSurface the surface of the task
      * @param startT the start transaction to be applied before the transition
      * @param finishT the finish transaction to restore states after the transition
-     * @return the window decoration object
+     * @return {@code true} if window decoration was created, {@code false} otherwise
      */
     boolean createWindowDecoration(
             ActivityManager.RunningTaskInfo taskInfo,
@@ -66,8 +66,9 @@ public interface WindowDecorViewModel {
      *
      * @param startT the start transaction to be applied before the transition
      * @param finishT the finish transaction to restore states after the transition
+     * @return {@code true} if window decoration exists, {@code false} otherwise
      */
-    void setupWindowDecorationForTransition(
+    boolean setupWindowDecorationForTransition(
             ActivityManager.RunningTaskInfo taskInfo,
             SurfaceControl.Transaction startT,
             SurfaceControl.Transaction finishT);
@@ -76,6 +77,7 @@ public interface WindowDecorViewModel {
      * Destroys the window decoration of the give task.
      *
      * @param taskInfo the info of the task
+     * @return {@code true} if window decoration was destroyed, {@code false} otherwise
      */
-    void destroyWindowDecoration(ActivityManager.RunningTaskInfo taskInfo);
+    boolean destroyWindowDecoration(ActivityManager.RunningTaskInfo taskInfo);
 }