Get Android device unique id

GetAndroidDeviceUid.java

    public static String getDeviceId(Context ctx) {

        TelephonyManager tm = (TelephonyManager) ctx.getSystemService(Context.TELEPHONY_SERVICE);

        String deviceId;

        if (tm.getDeviceId() != null) {

            deviceId = tm.getDeviceId();
        } else {

            deviceId = Settings.Secure.getString(
                    ctx.getApplicationContext().getContentResolver(),
                    Settings.Secure.ANDROID_ID);
        }
        return deviceId;
    }