private Handler fingerDetectedHandler = new Handler() {
        // @Override
        @SuppressLint("NewApi")
        public void handleMessage(Message msg) {
            Log.v(TAG, "Register - PREF_DEVICE_FOUND: " + pref.getBoolean(PREF_DEVICE_ATTACHED, false));
            if (pref.getBoolean(PREF_DEVICE_ATTACHED, false)) {
                new CaptureFingerprintTask().execute();
            }
        }
    };
...
  @Override
    public void SGFingerPresentCallback() {
        if (isOpenedDevice) {
            fingerDetectedHandler.sendMessage(new Message());
        }
    }