我正在尝试使用 RNFS.mkdir 创建目录，但出现警告“无法创建目录”...

"react-native-fs": "^2.18.0",
"react-native": "0.64.0",

我用来编写的函数如下：

const phoneStorageDir = RNFS.ExternalStorageDirectoryPath + '/MyApp/pictures/';
const createAppFolder = async () => {
  if (Platform.OS === 'android') {
    try {
      const granted = await PermissionsAndroid.request(
        PermissionsAndroid.PERMISSIONS.WRITE_EXTERNAL_STORAGE,
          title: 'Permissions for write access',
          message: 'Give permission to your storage to write a file',
          buttonPositive: 'ok',
      if (granted === PermissionsAndroid.RESULTS.GRANTED) {
        await RNFS.mkdir(phoneStorageDir);
      } else {
        console.log('permission denied');
        return;
    } catch (err) {