Merge "Prevent NPE in ActivityStack#shouldbeVisible." into oc-dev

3 files changed, 28 insertions, 4 deletions

diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index d348224df377..c5d5867633a9 100644
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -232,7 +232,7 @@ class ActivityStack<T extends StackWindowController> extends ConfigurationContai
     static final int STACK_VISIBLE = 1;
     // Stack is considered visible, but only becuase it has activity that is visible behind other
     // activities and there is a specific combination of stacks.
-    private static final int STACK_VISIBLE_ACTIVITY_BEHIND = 2;
+    static final int STACK_VISIBLE_ACTIVITY_BEHIND = 2;
 
     @VisibleForTesting
     /* The various modes for the method {@link #removeTask}. */
@@ -1652,7 +1652,7 @@ class ActivityStack<T extends StackWindowController> extends ConfigurationContai
 
         if (StackId.isBackdropToTranslucentActivity(mStackId)
                 && hasVisibleBehindActivity() && StackId.isHomeOrRecentsStack(topStackId)
-                && !topStack.topActivity().fullscreen) {
+                && (topStack.topActivity() == null || !topStack.topActivity().fullscreen)) {
             // The fullscreen or assistant stack should be visible if it has a visible behind
             // activity behind the home or recents stack that is translucent.
             return STACK_VISIBLE_ACTIVITY_BEHIND;
diff --git a/services/tests/servicestests/src/com/android/server/am/ActivityStackTests.java b/services/tests/servicestests/src/com/android/server/am/ActivityStackTests.java
index c87eaed5c954..711c36b8b1d4 100644
--- a/services/tests/servicestests/src/com/android/server/am/ActivityStackTests.java
+++ b/services/tests/servicestests/src/com/android/server/am/ActivityStackTests.java
@@ -21,6 +21,7 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
+import android.app.ActivityManager;
 import android.content.ComponentName;
 import android.content.pm.ActivityInfo;
 import android.platform.test.annotations.Presubmit;
@@ -97,4 +98,25 @@ public class ActivityStackTests extends ActivityTestsBase {
 
         testStack.stopActivityLocked(activityRecord);
     }
+
+    /**
+     * This test verifies that {@link ActivityStack#STACK_VISIBLE_ACTIVITY_BEHIND} is returned from
+     * {@link ActivityStack#shouldBeVisible(ActivityRecord)} from a fullscreen workspace stack with
+     * a visible behind activity when top focused stack is the home stack.
+     */
+    @Test
+    public void testShouldBeVisibleWithVisibleBehindActivity() throws Exception {
+        final ActivityManagerService service = createActivityManagerService();
+        final TaskRecord task = createTask(service, testActivityComponent,
+                ActivityManager.StackId.FULLSCREEN_WORKSPACE_STACK_ID);
+        final ActivityStack fullscreenWorkspaceStackId = task.getStack();
+        final ActivityStack homeStack = service.mStackSupervisor.getStack(
+                ActivityManager.StackId.HOME_STACK_ID, true /*createStaticStackIfNeeded*/,
+                true /*onTop*/);
+        final ActivityRecord activityRecord = createActivity(service, testActivityComponent, task);
+        service.mStackSupervisor.setFocusStackUnchecked("testEmptyStackShouldBeVisible", homeStack);
+        service.mStackSupervisor.requestVisibleBehindLocked(activityRecord, true);
+        assertEquals(ActivityStack.STACK_VISIBLE_ACTIVITY_BEHIND,
+                fullscreenWorkspaceStackId.shouldBeVisible(null /*starting*/));
+    }
 }
diff --git a/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java b/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java
index 28051f9b2f8c..9cfa542da9d1 100644
--- a/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java
+++ b/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java
@@ -151,9 +151,12 @@ public class ActivityTestsBase {
      * setup not available in the test environment. Also specifies an injector for
      */
     protected static class TestActivityStackSupervisor extends ActivityStackSupervisor {
+        private final ActivityDisplay mDisplay;
+
         public TestActivityStackSupervisor(ActivityManagerService service, Looper looper) {
             super(service, looper);
             mWindowManager = prepareMockWindowManager();
+            mDisplay = new ActivityDisplay();
         }
 
         // No home stack is set.
@@ -185,9 +188,8 @@ public class ActivityTestsBase {
 
         public <T extends ActivityStack> T createTestStack(ActivityManagerService service,
                 int stackId, boolean onTop) {
-            final ActivityDisplay display = new ActivityDisplay();
             final TestActivityContainer container =
-                    new TestActivityContainer(service, stackId, display, onTop);
+                    new TestActivityContainer(service, stackId, mDisplay, onTop);
             mActivityContainers.put(stackId, container);
             return (T) container.getStack();
         }