안드로이드 유일값 (UUID, Unique id/Device id)

Settings.Secure.ANDROID_ID 를 베이스로 UUID 생성

private static String getUUID(Context _context) {
    UUID uuid = null;
    String androidId = Settings.Secure.getString(_context.getContentResolver(), 
                                                           Settings.Secure.ANDROID_ID);
    if (androidId == null || androidId.isEmpty() || androidId.equals("9774d56d682e549c")) {
        uuid = UUID.randomUUID();
    } else {
        try {
            uuid = UUID.nameUUIDFromBytes(androidId.getBytes("UTF8"));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            uuid = UUID.randomUUID();
        }
    }
    return uuid.toString();
}