轉載 https://blog.csdn.net/android2me/article/details/69525975

private void checkPermission() {
    //檢查許可權（NEED_PERMISSION）是否被授權 PackageManager.PERMISSION_GRANTED表示同意授權
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        //使用者已經拒絕過一次，再次彈出許可權申請對話方塊需要給使用者一個解釋
 
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
            Toast.makeText(this, "請開通相關許可權，否則無法正常使用本應用！", Toast.LENGTH_SHORT).show();
        }
        //申請許可權
        ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE
 
}, 0);
        ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.READ_EXTERNAL_STORAGE}, 0);
    } else {
        Toast.makeText(this, "授權成功！", Toast.LENGTH_SHORT).show();
    }
}