private String getDeviceId() {

        TelephonyManager tManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
        String uuid = tManager.getDeviceId();

        String android_id = Secure.getString(this.getContentResolver(),
                Secure.ANDROID_ID);

        if (android_id == null) {
            return uuid;
        } else {
            return android_id;
        }
    }