Prevent NPE when dragging last bubble from expanded state

- We null out stackview when it's removed from the window, this happens
  when the last bubble is removed from the view
- When the last bubble is dragged out, we trigger some other updates
  these get applied *after* the remove step so stackview is null at that
  time. These updates are to set selected bubble to null & collapse the
  stack. These don't technically need to tell stackView about them.
- I don't think this is an ideal solution

Test: drag out last bubble while stack is expanded
Fixes: 157778325
Change-Id: Ia55bf3ba315599ed8afb390ad481e0d3700b1b97

packages/SystemUI/src/com/android/systemui/bubbles/BubbleController.java

@@ -705,6 +705,9 @@ public class BubbleController implements ConfigurationController.ConfigurationLi
      * the new params if the stack has been added.
      */
     private void updateWmFlags() {
+        if (mStackView == null) {
+            return;
+        }
         if (isStackExpanded() && !mImeVisible) {
             // If we're expanded, and the IME isn't visible, we want to be focusable. This ensures
             // that any taps within Bubbles (including on the ActivityView) results in Bubbles
@@ -716,7 +719,7 @@ public class BubbleController implements ConfigurationController.ConfigurationLi
             mWmLayoutParams.flags |= WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
         }
 
-        if (mStackView != null && mAddedToWindowManager) {
+        if (mAddedToWindowManager) {
             try {
                 mWindowManager.updateViewLayout(mStackView, mWmLayoutParams);
             } catch (IllegalArgumentException e) {
@@ -1235,24 +1238,23 @@ public class BubbleController implements ConfigurationController.ConfigurationLi
             }
             mDataRepository.removeBubbles(mCurrentUserId, bubblesToBeRemovedFromRepository);
 
-            if (update.addedBubble != null) {
+            if (update.addedBubble != null && mStackView != null) {
                 mDataRepository.addBubble(mCurrentUserId, update.addedBubble);
                 mStackView.addBubble(update.addedBubble);
-
             }
 
-            if (update.updatedBubble != null) {
+            if (update.updatedBubble != null && mStackView != null) {
                 mStackView.updateBubble(update.updatedBubble);
             }
 
             // At this point, the correct bubbles are inflated in the stack.
             // Make sure the order in bubble data is reflected in bubble row.
-            if (update.orderChanged) {
+            if (update.orderChanged && mStackView != null) {
                 mDataRepository.addBubbles(mCurrentUserId, update.bubbles);
                 mStackView.updateBubbleOrder(update.bubbles);
             }
 
-            if (update.selectionChanged) {
+            if (update.selectionChanged && mStackView != null) {
                 mStackView.setSelectedBubble(update.selectedBubble);
                 if (update.selectedBubble != null && update.selectedBubble.getEntry() != null) {
                     mNotificationGroupManager.updateSuppression(
@@ -1262,7 +1264,9 @@ public class BubbleController implements ConfigurationController.ConfigurationLi
 
             // Expanding? Apply this last.
             if (update.expandedChanged && update.expanded) {
-                mStackView.setExpanded(true);
+                if (mStackView != null) {
+                    mStackView.setExpanded(true);
+                }
             }
 
             for (NotifCallback cb : mCallbacks) {
@@ -1368,7 +1372,6 @@ public class BubbleController implements ConfigurationController.ConfigurationLi
     }
 
     /**
-     * Lets any listeners know if bubble state has changed.
      * Updates the visibility of the bubbles based on current state.
      * Does not un-bubble, just hides or un-hides.
      * Updates stack description for TalkBack focus.

packages/SystemUI/src/com/android/systemui/bubbles/BubbleData.java

@@ -417,7 +417,8 @@ public class BubbleData {
         if (mBubbles.size() == 1) {
             // Going to become empty, handle specially.
             setExpandedInternal(false);
-            setSelectedBubbleInternal(null);
+            // Don't use setSelectedBubbleInternal because we don't want to trigger an applyUpdate
+            mSelectedBubble = null;
         }
         if (indexToRemove < mBubbles.size() - 1) {
             // Removing anything but the last bubble means positions will change.

packages/SystemUI/src/com/android/systemui/bubbles/BubbleStackView.java

@@ -93,7 +93,6 @@ import com.android.systemui.shared.system.QuickStepContract;
 import com.android.systemui.shared.system.SysUiStatsLog;
 import com.android.systemui.statusbar.notification.collection.NotificationEntry;
 import com.android.systemui.statusbar.phone.CollapsedStatusBarFragment;
-import com.android.systemui.statusbar.phone.NotificationShadeWindowController;
 import com.android.systemui.util.DismissCircleView;
 import com.android.systemui.util.FloatingContentCoordinator;
 import com.android.systemui.util.RelativeTouchListener;
@@ -1504,7 +1503,9 @@ public class BubbleStackView extends FrameLayout
             // expanded view becomes visible on the screen. See b/126856255
             mExpandedViewContainer.setAlpha(0.0f);
             mSurfaceSynchronizer.syncSurfaceAndRun(() -> {
-                previouslySelected.setContentVisibility(false);
+                if (previouslySelected != null) {
+                    previouslySelected.setContentVisibility(false);
+                }
                 updateExpandedBubble();
                 requestUpdate();
 

packages/SystemUI/tests/src/com/android/systemui/bubbles/BubbleDataTest.java

@@ -537,7 +537,7 @@ public class BubbleDataTest extends SysuiTestCase {
         // Verify the selection was cleared.
         verifyUpdateReceived();
         assertThat(mBubbleData.isExpanded()).isFalse();
-        assertSelectionCleared();
+        assertThat(mBubbleData.getSelectedBubble()).isNull();
     }
 
     // EXPANDED / ADD / UPDATE