setAdjacentTaskFragments for paired TaskFragment

Bug: 190433129
Test: Tested with sample app
Change-Id: Ifa4cf3df77f053d2f5806290989329d3a2b47160

core/java/android/window/WindowContainerTransaction.java

@@ -506,15 +506,17 @@ public final class WindowContainerTransaction implements Parcelable {
      * {@link #setAdjacentRoots(WindowContainerToken, WindowContainerToken)}, but can be used with
      * fragmentTokens when that TaskFragments haven't been created (but will be created in the same
      * {@link WindowContainerTransaction}).
+     * To reset it, pass {@code null} for {@code fragmentToken2}.
      * @param fragmentToken1    client assigned unique token to create TaskFragment with specified
      *                          in {@link TaskFragmentCreationParams#getFragmentToken()}.
      * @param fragmentToken2    client assigned unique token to create TaskFragment with specified
-     *                          in {@link TaskFragmentCreationParams#getFragmentToken()}.
+     *                          in {@link TaskFragmentCreationParams#getFragmentToken()}. If it is
+     *                          {@code null}, the transaction will reset the adjacent TaskFragment.
      * @hide
      */
     @NonNull
     public WindowContainerTransaction setAdjacentTaskFragments(
-            @NonNull IBinder fragmentToken1, @NonNull IBinder fragmentToken2) {
+            @NonNull IBinder fragmentToken1, @Nullable IBinder fragmentToken2) {
         final HierarchyOp hierarchyOp =
                 new HierarchyOp.Builder(HierarchyOp.HIERARCHY_OP_TYPE_SET_ADJACENT_TASK_FRAGMENTS)
                         .setContainer(fragmentToken1)

libs/WindowManager/Jetpack/src/androidx/window/extensions/organizer/JetpackTaskFragmentOrganizer.java

@@ -116,6 +116,9 @@ class JetpackTaskFragmentOrganizer extends TaskFragmentOrganizer {
                 secondaryFragmentBounds, WINDOWING_MODE_MULTI_WINDOW, activityIntent,
                 activityOptions);
 
+        // Set adjacent to each other so that the containers below will be invisible.
+        wct.setAdjacentTaskFragments(launchingFragmentToken, secondaryFragmentToken);
+
         applyTransaction(wct);
     }
 
@@ -126,6 +129,7 @@ class JetpackTaskFragmentOrganizer extends TaskFragmentOrganizer {
      */
     void expandTaskFragment(WindowContainerTransaction wct, IBinder fragmentToken) {
         resizeTaskFragment(wct, fragmentToken, new Rect());
+        wct.setAdjacentTaskFragments(fragmentToken, null);
     }
 
     /**

libs/WindowManager/Jetpack/src/androidx/window/extensions/organizer/SplitPresenter.java

@@ -142,8 +142,9 @@ class SplitPresenter extends JetpackTaskFragmentOrganizer {
             resizeTaskFragmentIfRegistered(wct, secondaryContainer, secondaryRectBounds);
         }
 
-        // TODO(b/190433398): The primary container and the secondary container should also be set
-        // as adjacent (WCT#setAdjacentRoots) to make activities behind invisible.
+        // Set adjacent to each other so that the containers below will be invisible.
+        wct.setAdjacentTaskFragments(
+                primaryContainer.getTaskFragmentToken(), secondaryContainer.getTaskFragmentToken());
         applyTransaction(wct);
 
         mController.registerSplit(primaryContainer, primaryActivity, secondaryContainer, rule);
@@ -184,9 +185,6 @@ class SplitPresenter extends JetpackTaskFragmentOrganizer {
         primaryContainer.setLastRequestedBounds(primaryRectBounds);
         secondaryContainer.setLastRequestedBounds(secondaryRectBounds);
 
-        // TODO(b/190433398): The primary container and the secondary container should also be set
-        // as adjacent (WCT#setAdjacentRoots) to make activities behind invisible.
-
         mController.registerSplit(primaryContainer, launchingActivity, secondaryContainer,
                 rule);
     }

services/core/java/com/android/server/wm/TaskFragment.java

@@ -161,7 +161,8 @@ class TaskFragment extends WindowContainer<WindowContainer> {
     /** Avoid reentrant of {@link #removeImmediately()}. */
     private boolean mRemoving;
 
-    // The TaskFragment that adjacent to this one.
+    /** The TaskFragment that is adjacent to this one. */
+    @Nullable
     private TaskFragment mAdjacentTaskFragment;
 
     /**
@@ -282,9 +283,23 @@ class TaskFragment extends WindowContainer<WindowContainer> {
         mRemoteToken = new RemoteToken(this);
     }
 
-    void setAdjacentTaskFragment(TaskFragment taskFragment) {
-        mAdjacentTaskFragment = taskFragment;
-        taskFragment.mAdjacentTaskFragment = this;
+    void setAdjacentTaskFragment(@Nullable TaskFragment taskFragment) {
+        if (mAdjacentTaskFragment == taskFragment) {
+            return;
+        }
+        resetAdjacentTaskFragment();
+        if (taskFragment != null) {
+            mAdjacentTaskFragment = taskFragment;
+            taskFragment.setAdjacentTaskFragment(this);
+        }
+    }
+
+    private void resetAdjacentTaskFragment() {
+        // Reset the adjacent TaskFragment if its adjacent TaskFragment is also this TaskFragment.
+        if (mAdjacentTaskFragment != null && mAdjacentTaskFragment.mAdjacentTaskFragment == this) {
+            mAdjacentTaskFragment.mAdjacentTaskFragment = null;
+        }
+        mAdjacentTaskFragment = null;
     }
 
     void setTaskFragmentOrganizer(TaskFragmentOrganizerToken organizer, int pid) {
@@ -1951,6 +1966,7 @@ class TaskFragment extends WindowContainer<WindowContainer> {
             return;
         }
         mRemoving = true;
+        resetAdjacentTaskFragment();
         super.removeImmediately();
         sendTaskFragmentVanished();
         mRemoving = false;

services/core/java/com/android/server/wm/WindowOrganizerController.java

@@ -720,8 +720,10 @@ class WindowOrganizerController extends IWindowOrganizerController.Stub
                 fragmentToken = hop.getContainer();
                 final IBinder adjacentFragmentToken = hop.getAdjacentRoot();
                 final TaskFragment tf1 = mLaunchTaskFragments.get(fragmentToken);
-                final TaskFragment tf2 = mLaunchTaskFragments.get(adjacentFragmentToken);
-                if (tf1 == null || tf2 == null) {
+                final TaskFragment tf2 = adjacentFragmentToken != null
+                        ? mLaunchTaskFragments.get(adjacentFragmentToken)
+                        : null;
+                if (tf1 == null || (adjacentFragmentToken != null && tf2 == null)) {
                     final Throwable exception = new IllegalArgumentException(
                             "Not allowed to set adjacent on invalid fragment tokens");
                     sendTaskFragmentOperationFailure(organizer, errorCallbackToken, exception);