Consider adjacent launch target when recycling an existing task

If there's a launch target indicated while recycling an existing task,
consider to use the adjacent task of the launch target. So the existing
task won't be reparent to adjacent task redundantly.

Fix: 224901460
Test: atest ActivityStarterTests
Test: put single-instance app in split and make sure it gain focus,
      dropping the same app icon to another side of the split,
      observed it will switch split position without dismissing split
Change-Id: I4d4b4bcb6c036601a4fa68905ae66d91526bfe84

2 files changed, 41 insertions, 15 deletions

diff --git a/services/core/java/com/android/server/wm/ActivityStarter.java b/services/core/java/com/android/server/wm/ActivityStarter.java
index b97ee7ef76b3..b2f27ebaf513 100644
--- a/services/core/java/com/android/server/wm/ActivityStarter.java
+++ b/services/core/java/com/android/server/wm/ActivityStarter.java
@@ -2732,8 +2732,8 @@ class ActivityStarter {
         intentActivity.getTaskFragment().clearLastPausedActivity();
         Task intentTask = intentActivity.getTask();
 
-        // Only update the target-root-task when it is not indicated.
         if (mTargetRootTask == null) {
+            // Update launch target task when it is not indicated.
             if (mSourceRecord != null && mSourceRecord.mLaunchRootTask != null) {
                 // Inherit the target-root-task from source to ensure trampoline activities will be
                 // launched into the same root task.
@@ -2742,6 +2742,17 @@ class ActivityStarter {
                 mTargetRootTask = getOrCreateRootTask(mStartActivity, mLaunchFlags, intentTask,
                         mOptions);
             }
+        } else {
+            // If a launch target indicated, and the matching task is already in the adjacent task
+            // of the launch target. Adjust to use the adjacent task as its launch target. So the
+            // existing task will be launched into the closer one and won't be reparent redundantly.
+            // TODO(b/231541706): Migrate the logic to wm-shell after having proper APIs to help
+            //  resolve target task without actually starting the activity.
+            final Task adjacentTargetTask = mTargetRootTask.getAdjacentTaskFragment() != null
+                    ? mTargetRootTask.getAdjacentTaskFragment().asTask() : null;
+            if (adjacentTargetTask != null && intentActivity.isDescendantOf(adjacentTargetTask)) {
+                mTargetRootTask = adjacentTargetTask;
+            }
         }
 
         // If the target task is not in the front, then we need to bring it to the front...
@@ -2771,7 +2782,7 @@ class ActivityStarter {
                     intentActivity.setTaskToAffiliateWith(mSourceRecord.getTask());
                 }
 
-                if (mTargetRootTask == intentActivity.getRootTask()) {
+                if (intentActivity.isDescendantOf(mTargetRootTask)) {
                     // TODO(b/151572268): Figure out a better way to move tasks in above 2-levels
                     //  tasks hierarchies.
                     if (mTargetRootTask != intentTask
@@ -2818,19 +2829,6 @@ class ActivityStarter {
         mTargetRootTask = intentActivity.getRootTask();
         mSupervisor.handleNonResizableTaskIfNeeded(intentTask, WINDOWING_MODE_UNDEFINED,
                 mRootWindowContainer.getDefaultTaskDisplayArea(), mTargetRootTask);
-
-        // We need to check if there is a launch root task in TDA for this target root task.
-        // If it exist, we need to reparent target root task from TDA to launch root task.
-        final TaskDisplayArea tda = mTargetRootTask.getDisplayArea();
-        final Task launchRootTask = tda.getLaunchRootTask(mTargetRootTask.getWindowingMode(),
-                mTargetRootTask.getActivityType(), null /** options */, mSourceRootTask,
-                mLaunchFlags);
-        // If target root task is created by organizer, let organizer handle reparent itself.
-        if (!mTargetRootTask.mCreatedByOrganizer && launchRootTask != null
-                && launchRootTask != mTargetRootTask) {
-            mTargetRootTask.reparent(launchRootTask, POSITION_TOP);
-            mTargetRootTask = launchRootTask;
-        }
     }
 
     private void resumeTargetRootTaskIfNeeded() {
diff --git a/services/tests/wmtests/src/com/android/server/wm/ActivityStarterTests.java b/services/tests/wmtests/src/com/android/server/wm/ActivityStarterTests.java
index f59ec42a4a71..b9432753c17f 100644
--- a/services/tests/wmtests/src/com/android/server/wm/ActivityStarterTests.java
+++ b/services/tests/wmtests/src/com/android/server/wm/ActivityStarterTests.java
@@ -785,6 +785,34 @@ public class ActivityStarterTests extends WindowTestsBase {
     }
 
     /**
+     * This test ensures that {@link ActivityStarter#setTargetRootTaskIfNeeded} will task the
+     * adjacent task of indicated launch target into account. So the existing task will be launched
+     * into closer target.
+     */
+    @Test
+    public void testAdjustLaunchTargetWithAdjacentTask() {
+        // Create adjacent tasks and put one activity under it
+        final Task parent = new TaskBuilder(mSupervisor).build();
+        final Task adjacentParent = new TaskBuilder(mSupervisor).build();
+        parent.setAdjacentTaskFragment(adjacentParent, true);
+        final ActivityRecord activity = new ActivityBuilder(mAtm)
+                .setParentTask(parent)
+                .setCreateTask(true).build();
+
+        // Launch the activity to its adjacent parent
+        final ActivityOptions options = ActivityOptions.makeBasic()
+                .setLaunchRootTask(adjacentParent.mRemoteToken.toWindowContainerToken());
+        prepareStarter(FLAG_ACTIVITY_NEW_TASK, false /* mockGetRootTask */)
+                .setReason("testAdjustLaunchTargetWithAdjacentTask")
+                .setIntent(activity.intent)
+                .setActivityOptions(options.toBundle())
+                .execute();
+
+        // Verify the activity will be launched into the original parent
+        assertTrue(activity.isDescendantOf(parent));
+    }
+
+    /**
      * This test ensures that {@link ActivityStarter#setTargetRootTaskIfNeeded} will
      * move the existing task to front if the current focused root task doesn't have running task.
      */