Flutter HTTP包没有响应

Question

我正试图从我(用python(制作的API中获取数据到我的Flutter网站，但我要求API响应的代码块没有运行。我尝试了我所知道的一切，但给出的错误很奇怪。

这是我在中出错的代码

import 'package:http/http.dart' ;
import 'dart:convert';
const String url = 'http://localhost:5000/api?imagenumber=' ;
Future getImageIds(int image) async {
Response response = await get( url + image.toString()) ;
dynamic responsBody = response.body ;
dynamic decodedData = jsonDecode(responsBody) ;
return  decodedData ;
}

顺便说一下，API正在本地主机上运行(目前(。

这里是错误：

Performing hot restart...
Syncing files to device Chrome...
Restarted application in 605ms.
This if from screen 1: 1 , 2 , 3
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 1450:54                                              runUnary
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 143:18                                        handleValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 696:44                                        handleValueCallback
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 725:32                                        _propagateToListeners
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 519:7                                         [_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 (http://localhost:55081/dart_sdk.js:4361:12)
at Object._rethrow (http://localhost:55081/dart_sdk.js:38188:16)
at async._AsyncCallbackEntry.new.callback (http://localhost:55081/dart_sdk.js:38182:13)
at Object._microtaskLoop (http://localhost:55081/dart_sdk.js:38014:13)
at _startMicrotaskLoop (http://localhost:55081/dart_sdk.js:38020:13)
at http://localhost:55081/dart_sdk.js:33517:9

忽略前四行

Answer 1

您需要启用跨来源资源共享(CORS(才能发出请求。如果启用了CORS，您将不会再出现此错误。我也遇到了同样的问题，决定通过云功能提出请求。你可以考虑启用cors，可能有一种方法可以让它在谷歌chrome中进行测试。

添加：

<IfModule mod_headers.c>
Header set Access-Control-Allow-Origin "*"
</IfModule>

到您的服务器.htaccess