@Override
 public void onServiceConnected(ComponentName name, IBinder service) {
   USBConnectionService remoteStubService = USBConnectionService.Stub.asInterface(service);
   try {
     callback.onUSBConnected(remoteStubService.isConnected());
   } catch (RemoteException e) {
     callback.onUSBConnectionError(e);
     e.printStackTrace();
   } finally {
     context.unbindService(usbConnectionService);
   }
 }
 public void checkUSBConnection() {
   // final String servicename = "de.uniulm.bagception.service.USBConnectionServiceRemote";
   final String servicename = ServiceNames.RFID_SERVICE;
   if (!context.bindService(
       new Intent(servicename), usbConnectionService, Context.BIND_AUTO_CREATE)) {
     callback.onUSBConnectionError(new Exception("error binding to connection service"));
   }
 }