我试图开发一个flutter应用程序，发送超文本传输协议请求到远程PHP文件托管在000webHost。

当我为桌面构建我的Flutter应用程序时，我设法检索信息，一切都很好。但是，由于另一个问题（视频播放器不适用于桌面……），我想回到Web构建。

我看了几篇文章，但我没有发现类似于我的错误。有些人说由于跨源请求（CORS）的错误，但在我看来不是这个问题。

当我尝试使用http.post检索数据时，会出现以下错误：

browser_client.dart:87 POST https://<myadresse>.000webhostapp.com/<nameFile>.php net::ERR_HTTP2_PROTOCOL_ERROR

Uncaught (in promise) Error: XMLHttpRequest error.
    C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/core_patch.dart 906:28  get current packages/http/src/browser_client.dart 84:22                                                                                    <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/zone.dart 1446:54                                              runUnary
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 150:18                                        handleValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 703:44                                        handleValueCallback
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 732:32                                        _propagateToListeners
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 526:7                                         [_complete]
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream_pipe.dart 61:11                                         _cancelAndValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream.dart 1302:7                                             <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 324:14  _checkAndCall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 329:39  dcall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/html/dart2js/html_dart2js.dart 37312:58                              <fn>

    at Object.createErrorWithStack (errors.dart:249)
    at Object._rethrow (async_patch.dart:200)
    at async._AsyncCallbackEntry.new.callback (zone.dart:1171)
    at Object._microtaskLoop (schedule_microtask.dart:41)
    at _startMicrotaskLoop (schedule_microtask.dart:50)
    at async_patch.dart:166

我的代码：

 void fetchData() async {
    /**Map for instructions with php**/
    var map = Map<String, dynamic>();
    HandlerResponse
        handlerResponse2; //Use to manage errors and parsing of received responses

    map['action'] = Constants.GET_ALL_OPERATIONS;

    try {
      //Retrieving the response with the file containing the accesses to the database
      http.Response responseCall = await http.post(Constants.ROOT,
          body: map, headers: {"Access-Control-Allow-Origin": "*" , "Access-Control-Allow-Credentials": "true"});

      //Definition of the behavior to adopt upon receipt of the response
      handlerResponse2 = HandlerResponse(parseReponse: parseResponse);

      //Recovery of response processing
      _operations =
          handlerResponse2.response(responseCall); //response(responseCall);

     
     //Notify the change to widgets using the provider to update the interface
      notifyListeners();
    } on SocketException {
      throw FetchDataException('No Internet connection');
    }
  }

当我使用flutter医生：

flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel dev, 1.25.0-4.0.pre, on Microsoft Windows [version 10.0.18362.900], locale fr-FR)
[√] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[√] Chrome - develop for the web
[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.4.5)
[√] Android Studio (version 4.0)
[√] Connected device (3 available)

• No issues found!

提前谢谢你的帮助