错误：使用天气 API 时出现 XMLHttpRequest 错误

Posted 2023-02-23

【中文标题】错误：使用天气 API 时出现 XMLHttpRequest 错误

【英文标题】：ERROR : XMLHttpRequest error in flutter while using weather API

【发布时间】：2022-01-16 19:06:24

【问题描述】：

这里我使用天气 API。在进行调试时会出现错误，

错误：XMLHttpRequest 错误。 C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/core_patch.dart 908:28 获取当前 包/http/src/browser_client.dart 69:22 C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/zone.dart 1687:54 runUnary C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 160:18 handleValue C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 767:44 handleValueCallback C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 796:13 _propagateToListeners C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 593:7 [_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 1232:7 C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 334:14 _checkAndCall C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 339:39 dcall C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/html/dart2js/html_dart2js.dart 37332:58 在 Object.createErrorWithStack (http://localhost:51980/dart_sdk.js:5388:12) 在 Object._rethrow (http://localhost:51980/dart_sdk.js:40987:16) 在 async._AsyncCallbackEntry.new.callback (http://localhost:51980/dart_sdk.js:40981:13) 在 Object._microtaskLoop (http://localhost:51980/dart_sdk.js:40808:13) 在 _startMicrotaskLoop (http://localhost:51980/dart_sdk.js:40814:13) 在 http://localhost:51980/dart_sdk.js:36279:9

我的颤振代码是：

    String searchApiUrl = 'https://www.metaweather.com/api/location/search/?query=';
    String locationApiUrl = 'https://www.metaweather.com/api/location/';


    void fetchSearch(String input) async 
     var searchResult = await http.get(Uri.parse(searchApiUrl + input), headers: "Accept": 
      "application/json","Access-Control-Allow-Origin": "*");
  
     var result = json.decode(searchResult.body)[0];

   setState(() 
    location = result["title"];
    woeid = result["woeid"];
);

    void fetchLocation() async 
     var locationResult = await http.get(Uri.parse(locationApiUrl + woeid.toString()), 
      headers: "Accept": "application/json","Access-Control-Allow-Origin": "*");
     var result = json.decode(locationResult.body);
     var consolidated_weather = result["consolidated_weather"];
     var data = consolidated_weather[0];

   setState(() 
    temperature = data["the_temp"].round();
    weather = data["weather_state_name"].replaceAll(' ','').toLowerCase();
);

   void onTextFieldSubmitted(String input)
    fetchSearch(input);
    fetchLocation();

【参考方案1】：

在fetchLocation 中，您依赖于来自fetchSearch 的woeid 值，但您无需等待onTextFieldSubmitted 中的结果。试试这个：

void onTextFieldSubmitted(String input) async 
    await fetchSearch(input);
    await fetchLocation(); // await in this line might not be needed