如何在flutter中设置dio package？

Question

I want to create flutter apps for downloading files from inte.net but when i use the dio package , I get the error; The named parameter 'onProgress' isn't defined, what should I do?

my function

 Future<void> downloadFile() async {
    Dio dio = Dio();

    try {
      var dir = await getApplicationDocumentsDirectory();

      await dio.download(imgUrl, "${dir.path}/myimage.jpg",
          onProgress: (rec, total) {
            print("Rec: $rec , Total: $total");

            setState(() {
              downloading = true;
              progressString = ((rec / total) * 100).toStringAsFixed(0) + "%";
            });
          });
    } catch (e) {
      print(e);
    }

    setState(() {
      downloading = false;
      progressString = "Completed";
    });
    print("Download completed");
  }

Answer 1

Replace onProgress with onReceiveProgress .

Always check the function implementation when issues like this occurred.

Answer 2

The method signature for the download method in Dio 4.0.0 is the following:

Future<Response> download(
    String urlPath,
    savePath, {
    ProgressCallback? onReceiveProgress,
    Map<String, dynamic>? queryParameters,
    CancelToken? cancelToken,
    bool deleteOnError = true,
    String lengthHeader = Headers.contentLengthHeader,
    data,
    Options? options,
  });

So you should use onReceiveProgress instead of onProgress .

Background information

onProgress was the initial parameter that was used when the Dio package was created. This has been changed in the v2.0.14 release . It seems like a small part of the initial code docs remained intact since that release.

If that is what confused you, it might be a good thing to open an issue on the Dio GitHub project.