小编Mic*_*awa的帖子

我似乎无法弄清楚如何解决此错误。这以前是有效的，但现在升级到 Flutter Null Safety 版本后会产生此错误：

我正在使用屏幕截图：用于 ScreenshotController 的 ^1.0.0-nullsafety.1 包

File _imageFile;
ScreenshotController screenshotController = ScreenshotController();

IconButton(
            icon: Icon(Icons.download_sharp),
            onPressed: () {
              
              Directory directory;
              _requestPermission(Permission.storage);
              try {
                _imageFile = null;
                screenshotController
                    .capture(delay: Duration(milliseconds: 10))
                    .then((File image) async {
                  //print("Capture Done");
                  setState(() {
                    _imageFile = image;
                  });

                  if (await _requestPermission(Permission.storage)) {
                    directory = await getExternalStorageDirectory();

                    String newPath = '';
                    List<String> folders = directory.path.split('/');


                    for (int x = 1; x < folders.length; x++) {
                      String folder = folders[x];
                      if (folder != 'Android') …