Android 11：在try 获取文件的永久权限后，仍然没有读写权限

我希望用户 Select 一个文件.我是这样做的:

        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);
        intent.setType("*/*");
        startActivityForResult(intent, Aux.ACTIVITY_REQUEST_CODE_SELECT_CCRYPT_ONLY);

然后，我对活动结果执行此操作.

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode,resultCode,data);

    if (resultCode == RESULT_OK){
        if (requestCode == Aux.ACTIVITY_REQUEST_CODE_SELECT_CCRYPT_ONLY){

            Uri dataFileUri = data.getData();

            Aux.DbugCcrypt("Storing the URI of the Work Directory In Shared Preferences: " + dataFileUri.toString());
            Aux.storeStringInSharedPreferences(this,Aux.SHARED_PREF_STRING_KEY,dataFileUri.toString());

            // And now we take persistent permission.
            ContentResolver cr = this.getContentResolver();
            cr.takePersistableUriPermission(dataFileUri, (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION));

        }
    }
    else {
        // TODO Handle.
        Aux.DbugCcrypt("On Activity Result was not OK.");
    }
}

因此，基本上我将URI字符串存储在共享首选项中，并请求对该文件的持久权限.

然后我关闭应用程序.然后再把它打开.

我这样做:

    DbugCcrypt("Getting the Shared Preference URI");
    String dataAuxUriString = getStringInSharedPreferences(context,SHARED_PREF_STRING_KEY);
    if (!dataAuxUriString.isEmpty()){
        DbugCcrypt("Got the URI File. Testing Read/Write" );
        Uri dataAuxUri= Uri.parse(dataAuxUriString);
        File testFile = new File(dataAuxUri.getPath());
        if (testFile.isDirectory()){
            DbugCcrypt("Is a directory");
        }
        else {
            DbugCcrypt("Data Aux File URI. Can Read: " + testFile.canRead());
            DbugCcrypt("Data Aux File URI. Can Write: " + testFile.canWrite());
        }
    }
    else {
        DbugCcrypt("Data Aux URI String is empty");
    }

返回此打印输出(DBugCCcrypt只是调用System.err.println("[Stuf]"+Message))

[CCRYPT_DBUG] Getting the Shared Preference URI
[CCRYPT_DBUG] Got the URI File. Testing Read/Write
[CCRYPT_DBUG] Data Aux File URI. Can Read: false
[CCRYPT_DBUG] Data Aux File URI. Can Write: false

所以我的问题是，为什么我不能在应用程序执行之间获得对文件的读/写权限？