Merge "Make sure the secondary TaskFragment is above the primary" into tm-qpr-dev

libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/SplitController.java

@@ -792,6 +792,9 @@ public class SplitController implements JetpackTaskFragmentOrganizer.TaskFragmen
      * Checks if there is a rule to split the two activities. If there is one, puts them into split
      * and returns {@code true}. Otherwise, returns {@code false}.
      */
+    // Suppress GuardedBy warning because lint ask to mark this method as
+    // @GuardedBy(mPresenter.mController.mLock), which is mLock itself
+    @SuppressWarnings("GuardedBy")
     @GuardedBy("mLock")
     private boolean putActivitiesIntoSplitIfNecessary(@NonNull WindowContainerTransaction wct,
             @NonNull Activity primaryActivity, @NonNull Activity secondaryActivity) {

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

@@ -38,6 +38,7 @@ import android.view.WindowInsets;
 import android.view.WindowMetrics;
 import android.window.WindowContainerTransaction;
 
+import androidx.annotation.GuardedBy;
 import androidx.annotation.IntDef;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -171,6 +172,7 @@ class SplitPresenter extends JetpackTaskFragmentOrganizer {
      *                          created and the activity will be re-parented to it.
      * @param rule The split rule to be applied to the container.
      */
+    @GuardedBy("mController.mLock")
     void createNewSplitContainer(@NonNull WindowContainerTransaction wct,
             @NonNull Activity primaryActivity, @NonNull Activity secondaryActivity,
             @NonNull SplitPairRule rule) {
@@ -187,8 +189,10 @@ class SplitPresenter extends JetpackTaskFragmentOrganizer {
         final TaskFragmentContainer curSecondaryContainer = mController.getContainerWithActivity(
                 secondaryActivity);
         TaskFragmentContainer containerToAvoid = primaryContainer;
-        if (rule.shouldClearTop() && curSecondaryContainer != null) {
+        if (curSecondaryContainer != null
-            // Do not reuse the current TaskFragment if the rule is to clear top.
+                && (rule.shouldClearTop() || primaryContainer.isAbove(curSecondaryContainer))) {
+            // Do not reuse the current TaskFragment if the rule is to clear top, or if it is below
+            // the primary TaskFragment.
             containerToAvoid = curSecondaryContainer;
         }
         final TaskFragmentContainer secondaryContainer = prepareContainerForActivity(wct,

libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/TaskContainer.java

@@ -162,4 +162,8 @@ class TaskContainer {
         }
         return null;
     }
+
+    int indexOf(@NonNull TaskFragmentContainer child) {
+        return mContainers.indexOf(child);
+    }
 }

libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/TaskFragmentContainer.java

@@ -501,6 +501,18 @@ class TaskFragmentContainer {
         return new Size(maxMinWidth, maxMinHeight);
     }
 
+    /** Whether the current TaskFragment is above the {@code other} TaskFragment. */
+    boolean isAbove(@NonNull TaskFragmentContainer other) {
+        if (mTaskContainer != other.mTaskContainer) {
+            throw new IllegalArgumentException(
+                    "Trying to compare two TaskFragments in different Task.");
+        }
+        if (this == other) {
+            throw new IllegalArgumentException("Trying to compare a TaskFragment with itself.");
+        }
+        return mTaskContainer.indexOf(this) > mTaskContainer.indexOf(other);
+    }
+
     @Override
     public String toString() {
         return toString(true /* includeContainersToFinishOnExit */);

libs/WindowManager/Jetpack/tests/unittest/src/androidx/window/extensions/embedding/SplitPresenterTest.java

@@ -39,6 +39,7 @@ import static com.android.dx.mockito.inline.extended.ExtendedMockito.verify;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
@@ -247,6 +248,26 @@ public class SplitPresenterTest {
         verify(mPresenter).expandTaskFragment(mTransaction, secondaryTf.getTaskFragmentToken());
     }
 
+    @Test
+    public void testCreateNewSplitContainer_secondaryAbovePrimary() {
+        final Activity secondaryActivity = createMockActivity();
+        final TaskFragmentContainer bottomTf = mController.newContainer(secondaryActivity, TASK_ID);
+        final TaskFragmentContainer primaryTf = mController.newContainer(mActivity, TASK_ID);
+        final SplitPairRule rule = new SplitPairRule.Builder(pair ->
+                pair.first == mActivity && pair.second == secondaryActivity, pair -> false,
+                metrics -> true)
+                .setShouldClearTop(false)
+                .build();
+
+        mPresenter.createNewSplitContainer(mTransaction, mActivity, secondaryActivity, rule);
+
+        assertEquals(primaryTf, mController.getContainerWithActivity(mActivity));
+        final TaskFragmentContainer secondaryTf = mController.getContainerWithActivity(
+                secondaryActivity);
+        assertNotEquals(bottomTf, secondaryTf);
+        assertTrue(secondaryTf.isAbove(primaryTf));
+    }
+
     private Activity createMockActivity() {
         final Activity activity = mock(Activity.class);
         final Configuration activityConfig = new Configuration();

libs/WindowManager/Jetpack/tests/unittest/src/androidx/window/extensions/embedding/TaskFragmentContainerTest.java

@@ -287,6 +287,18 @@ public class TaskFragmentContainerTest {
         assertEquals(1, container.collectNonFinishingActivities().size());
     }
 
+    @Test
+    public void testIsAbove() {
+        final TaskContainer taskContainer = new TaskContainer(TASK_ID);
+        final TaskFragmentContainer container0 = new TaskFragmentContainer(null /* activity */,
+                mIntent, taskContainer, mController);
+        final TaskFragmentContainer container1 = new TaskFragmentContainer(null /* activity */,
+                mIntent, taskContainer, mController);
+
+        assertTrue(container1.isAbove(container0));
+        assertFalse(container0.isAbove(container1));
+    }
+
     @Test
     public void testGetBottomMostActivity() {
         final TaskContainer taskContainer = new TaskContainer(TASK_ID);