在 android 的外部存储中创建目录失败

Failed making directory in external storage in android

我有这个方法,但为什么在图片文件夹中创建目录失败?

    private void CreateDirectoryForPictures()
    {
        App._dir = new File(
            Android.OS.Environment.GetExternalStoragePublicDirectory(
                Android.OS.Environment.DirectoryPictures), "CameraAppDemo");
        if (!App._dir.Exists())
        {
            App._dir.Mkdirs();
        }
        if (!App._dir.Exists())
        {
            Toast.MakeText(this, "Directory not created", ToastLength.Short).Show();
        }
        else
        {
            Toast.MakeText(this, "Directory created", ToastLength.Short).Show();
        }

    }

您是否在清单中添加了 WRITE_EXTERNAL_STORAGE 权限?