diff --git a/quickstep/src/com/android/quickstep/views/GroupedTaskView.java b/quickstep/src/com/android/quickstep/views/GroupedTaskView.java
index 30b55a8..df99d27 100644
--- a/quickstep/src/com/android/quickstep/views/GroupedTaskView.java
+++ b/quickstep/src/com/android/quickstep/views/GroupedTaskView.java
@@ -74,7 +74,7 @@
     }
 
     public void bind(Task primary, Task secondary, RecentsOrientedState orientedState,
-            StagedSplitBounds splitBoundsConfig) {
+            @Nullable StagedSplitBounds splitBoundsConfig) {
         super.bind(primary, orientedState);
         mSecondaryTask = secondary;
         mTaskIdContainer[1] = secondary.key.id;
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index 0188962..7efe879 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -838,6 +838,7 @@
      * Update the thumbnail of the task.
      * @param refreshNow Refresh immediately if it's true.
      */
+    @Nullable
     public TaskView updateThumbnail(int taskId, ThumbnailData thumbnailData, boolean refreshNow) {
         TaskView taskView = getTaskViewByTaskId(taskId);
         if (taskView != null) {
@@ -1043,6 +1044,7 @@
         return getLastGridTaskView(getTopRowIdArray(), getBottomRowIdArray());
     }
 
+    @Nullable
     private TaskView getLastGridTaskView(IntArray topRowIdArray, IntArray bottomRowIdArray) {
         if (topRowIdArray.isEmpty() && bottomRowIdArray.isEmpty()) {
             return null;