@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // 如果api >= 23 需要顯式申請許可權，程式碼舉例如下：
        if (Build.VERSION.SDK_INT >= 23) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED
                    || ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                    || ContextCompat.checkSelfPermission(this, Manifest.permission.INTERNET) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,
                        Manifest.permission.READ_PHONE_STATE, Manifest.permission.INTERNET}, 0);
            }
        }

        setContentView(R.layout.main);