diff --git a/quickstep/src/com/android/quickstep/TouchInteractionService.java b/quickstep/src/com/android/quickstep/TouchInteractionService.java
index 58bb8fc..e10b56d 100644
--- a/quickstep/src/com/android/quickstep/TouchInteractionService.java
+++ b/quickstep/src/com/android/quickstep/TouchInteractionService.java
@@ -512,6 +512,9 @@
 
                 private boolean isTrackpadDevice(int deviceId) {
                     InputDevice inputDevice = mInputManager.getInputDevice(deviceId);
+                    if (inputDevice == null) {
+                        return false;
+                    }
                     return inputDevice.getSources() == (InputDevice.SOURCE_MOUSE
                             | InputDevice.SOURCE_TOUCHPAD);
                 }