diff --git a/android/src/main/java/com/xiarui/zhiwen/UsbController.java b/android/src/main/java/com/xiarui/zhiwen/UsbController.java
index f79eefd..addf2a7 100644
--- a/android/src/main/java/com/xiarui/zhiwen/UsbController.java
+++ b/android/src/main/java/com/xiarui/zhiwen/UsbController.java
@@ -142,8 +142,13 @@ public class UsbController {
             if (intent.getAction().equals(ACTION_USB_PERMISSION)) {
                 if (!intent.getBooleanExtra(
                         UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
-                    mPermissionListener.onPermissionDenied(intent
-                            .getParcelableExtra(UsbManager.EXTRA_DEVICE));
+                    UsbDevice device = intent
+                            .getParcelableExtra(UsbManager.EXTRA_DEVICE);
+                    if (device != null) {
+                        mPermissionListener.onPermissionDenied(device);
+                    } else {
+                        l("Permission denied (device extra is null)");
+                    }
 
                     mConnectionHandler.onUsbPermissionDenied();
                 } else {