diff --git a/core/java/android/app/ActivityTransitionCoordinator.java b/core/java/android/app/ActivityTransitionCoordinator.java
index d02d17febbfb9..137f77d038b6a 100644
--- a/core/java/android/app/ActivityTransitionCoordinator.java
+++ b/core/java/android/app/ActivityTransitionCoordinator.java
@@ -196,7 +196,7 @@ abstract class ActivityTransitionCoordinator extends ResultReceiver {
     final protected ArrayList<String> mAllSharedElementNames;
     final protected ArrayList<View> mSharedElements = new ArrayList<View>();
     final protected ArrayList<String> mSharedElementNames = new ArrayList<String>();
-    final protected ArrayList<View> mTransitioningViews = new ArrayList<View>();
+    protected ArrayList<View> mTransitioningViews = new ArrayList<View>();
     protected SharedElementCallback mListener;
     protected ResultReceiver mResultReceiver;
     final private FixedEpicenterCallback mEpicenterCallback = new FixedEpicenterCallback();
@@ -222,7 +222,7 @@ abstract class ActivityTransitionCoordinator extends ResultReceiver {
         mListener.onMapSharedElements(mAllSharedElementNames, sharedElements);
         mSharedElementNames.addAll(sharedElements.keySet());
         mSharedElements.addAll(sharedElements.values());
-        if (getViewsTransition() != null) {
+        if (getViewsTransition() != null && mTransitioningViews != null) {
             ViewGroup decorView = getDecor();
             if (decorView != null) {
                 decorView.captureTransitioningViews(mTransitioningViews);
@@ -233,6 +233,9 @@ abstract class ActivityTransitionCoordinator extends ResultReceiver {
     }
 
     protected void stripOffscreenViews() {
+        if (mTransitioningViews == null) {
+            return;
+        }
         Rect r = new Rect();
         for (int i = mTransitioningViews.size() - 1; i >= 0; i--) {
             View view = mTransitioningViews.get(i);
@@ -592,7 +595,7 @@ abstract class ActivityTransitionCoordinator extends ResultReceiver {
         // Clear the state so that we can't hold any references accidentally and leak memory.
         mWindow = null;
         mSharedElements.clear();
-        mTransitioningViews.clear();
+        mTransitioningViews = null;
         mOriginalAlphas.clear();
         mResultReceiver = null;
         mPendingTransition = null;
diff --git a/core/java/android/app/EnterTransitionCoordinator.java b/core/java/android/app/EnterTransitionCoordinator.java
index bfdb0eb56e249..16a3575933eb9 100644
--- a/core/java/android/app/EnterTransitionCoordinator.java
+++ b/core/java/android/app/EnterTransitionCoordinator.java
@@ -115,7 +115,7 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
         super.viewsReady(sharedElements);
         mIsReadyForTransition = true;
         hideViews(mSharedElements);
-        if (getViewsTransition() != null) {
+        if (getViewsTransition() != null && mTransitioningViews != null) {
             hideViews(mTransitioningViews);
         }
         if (mIsReturning) {
@@ -249,7 +249,7 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
             mIsCanceled = true;
             if (getViewsTransition() == null || mIsViewsTransitionStarted) {
                 showViews(mSharedElements, true);
-            } else {
+            } else if (mTransitioningViews != null) {
                 mTransitioningViews.addAll(mSharedElements);
             }
             mSharedElementNames.clear();
@@ -416,7 +416,7 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
         Transition viewsTransition = null;
         if (startEnterTransition) {
             mIsViewsTransitionStarted = true;
-            if (!mTransitioningViews.isEmpty()) {
+            if (mTransitioningViews != null && !mTransitioningViews.isEmpty()) {
                 viewsTransition = configureTransition(getViewsTransition(), true);
                 if (viewsTransition != null && !mIsReturning) {
                     stripOffscreenViews();
@@ -426,11 +426,14 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
                 viewTransitionComplete();
             } else {
                 viewsTransition.forceVisibility(View.INVISIBLE, true);
+                final ArrayList<View> transitioningViews = mTransitioningViews;
                 viewsTransition.addListener(new ContinueTransitionListener() {
                     @Override
                     public void onTransitionStart(Transition transition) {
                         mEnterViewsTransition = transition;
-                        showViews(mTransitioningViews, false);
+                        if (transitioningViews != null) {
+                            showViews(transitioningViews, false);
+                        }
                         super.onTransitionStart(transition);
                     }
 
@@ -451,7 +454,8 @@ class EnterTransitionCoordinator extends ActivityTransitionCoordinator {
             TransitionManager.beginDelayedTransition(decorView, transition);
             if (startSharedElementTransition && !mSharedElementNames.isEmpty()) {
                 mSharedElements.get(0).invalidate();
-            } else if (startEnterTransition && !mTransitioningViews.isEmpty()) {
+            } else if (startEnterTransition && mTransitioningViews != null &&
+                    !mTransitioningViews.isEmpty()) {
                 mTransitioningViews.get(0).invalidate();
             }
         } else {
diff --git a/core/java/android/app/ExitTransitionCoordinator.java b/core/java/android/app/ExitTransitionCoordinator.java
index 41b0db6387ae7..812dfdb41d744 100644
--- a/core/java/android/app/ExitTransitionCoordinator.java
+++ b/core/java/android/app/ExitTransitionCoordinator.java
@@ -126,7 +126,9 @@ class ExitTransitionCoordinator extends ActivityTransitionCoordinator {
     }
 
     public void resetViews() {
-        showViews(mTransitioningViews, true);
+        if (mTransitioningViews != null) {
+            showViews(mTransitioningViews, true);
+        }
         showViews(mSharedElements, true);
         mIsHidden = true;
         ViewGroup decorView = getDecor();
@@ -253,7 +255,7 @@ class ExitTransitionCoordinator extends ActivityTransitionCoordinator {
     private void startExitTransition() {
         Transition transition = getExitTransition();
         ViewGroup decorView = getDecor();
-        if (transition != null && decorView != null) {
+        if (transition != null && decorView != null && mTransitioningViews != null) {
             TransitionManager.beginDelayedTransition(decorView, transition);
             mTransitioningViews.get(0).invalidate();
         } else {
@@ -289,19 +291,20 @@ class ExitTransitionCoordinator extends ActivityTransitionCoordinator {
 
     private Transition getExitTransition() {
         Transition viewsTransition = null;
-        if (!mTransitioningViews.isEmpty()) {
+        if (mTransitioningViews != null && !mTransitioningViews.isEmpty()) {
             viewsTransition = configureTransition(getViewsTransition(), true);
         }
         if (viewsTransition == null) {
             exitTransitionComplete();
         } else {
+            final ArrayList<View> transitioningViews = mTransitioningViews;
             viewsTransition.addListener(new ContinueTransitionListener() {
                 @Override
                 public void onTransitionEnd(Transition transition) {
                     transition.removeListener(this);
                     exitTransitionComplete();
-                    if (mIsHidden) {
-                        showViews(mTransitioningViews, true);
+                    if (mIsHidden && transitioningViews != null) {
+                        showViews(transitioningViews, true);
                     }
                     if (mSharedElementBundle != null) {
                         delayCancel();