Merge "Exit split-screen when primary stack moved behind a fullscreen stack."

services/core/java/com/android/server/am/ActivityStack.java

@@ -1013,6 +1013,14 @@ class ActivityStack<T extends StackWindowController> extends ConfigurationContai
             return;
         }
 
+        /**
+         * The intent behind moving a primary split screen stack to the back is usually to hide
+         * behind the home stack. Exit split screen in this case.
+         */
+        if (getWindowingMode() == WINDOWING_MODE_SPLIT_SCREEN_PRIMARY) {
+            setWindowingMode(WINDOWING_MODE_FULLSCREEN);
+        }
+
         getDisplay().positionChildAtBottom(this);
         mStackSupervisor.setFocusStackUnchecked(reason, getDisplay().getTopStack());
         if (task != null) {

services/tests/servicestests/src/com/android/server/am/ActivityStackTests.java

@@ -47,7 +47,7 @@ import org.junit.Test;
  * Tests for the {@link ActivityStack} class.
  *
  * Build/Install/Run:
- *  bit FrameworksServicesTests:com.android.server.am.ActivityStackTests
+ *  atest ActivityStackTests
  */
 @SmallTest
 @Presubmit
@@ -103,6 +103,29 @@ public class ActivityStackTests extends ActivityTestsBase {
         assertEquals(mStack.mResumedActivity, r);
     }
 
+    @Test
+    public void testPrimarySplitScreenToFullscreenWhenMovedToBack() throws Exception {
+        // Create primary splitscreen stack. This will create secondary stacks and places the
+        // existing fullscreen stack on the bottom.
+        final ActivityStack primarySplitScreen = mService.mStackSupervisor.getDefaultDisplay()
+                .createStack(WINDOWING_MODE_SPLIT_SCREEN_PRIMARY, ACTIVITY_TYPE_STANDARD,
+                        true /* onTop */);
+
+        // Assert windowing mode.
+        assertEquals(primarySplitScreen.getWindowingMode(), WINDOWING_MODE_SPLIT_SCREEN_PRIMARY);
+
+        // Move primary to back.
+        primarySplitScreen.moveToBack("testPrimarySplitScreenToFullscreenWhenMovedToBack",
+                null /* task */);
+
+        // Assert that stack is at the bottom.
+        assertEquals(mService.mStackSupervisor.getDefaultDisplay().getIndexOf(primarySplitScreen),
+                0);
+
+        // Ensure no longer in splitscreen.
+        assertEquals(primarySplitScreen.getWindowingMode(), WINDOWING_MODE_FULLSCREEN);
+    }
+
     @Test
     public void testStopActivityWhenActivityDestroyed() throws Exception {
         final ActivityRecord r = new ActivityBuilder(mService).setTask(mTask).build();