我的代码中有什么错误，如何成功解析 json 中的数据？

Question

我正在 Flutter 中开发天气应用程序并遇到一个问题，当我们在搜索栏中输入城市名称并单击下一个图标时，它会在屏幕上显示该特定地点的天气。 但是为了确保正确解析数据，我只在控制台中调用数据。 虽然代码没有显示错误，但控制台中会抛出多个错误。 谁能告诉我如何解决此错误并成功解析此数据？

控制台中显示的错误如下：

对不起，代码中的实际错误如下：

观察站调试器和分析器在Chrome，请访问： http://127.0.0.1:50548/vYt04KYoAA8=的颤振DevTools调试器和分析器在Chrome，请访问： http://127.0.0.1:9101?uri=http:/ /127.0.0.1:50548/vYt04KYoAA8= {"cod":"400","message":"Nothing to geocode"} 错误：异常：无法在 Object.throw_ [as throw] (http://localhost :50501/dart_sdk.js:5061:11) 在 getWeather (http://localhost:50501/packages/finalproject/Weatherproj/data_service.dart.lib.js:31:21) 在 getWeather.next () 在 http:// /localhost:50501/dart_sdk.js:38640:33 在 _RootZone.runUnary (http://localhost:50501/dart_sdk.js:38511:59) 在 _FutureListener.thenAwait.handleValue (http://localhost:50501/dart_sdk. js:33713:29) at handleValueCallback (http://localhost:50501/dart_sdk.js:34265:49) at Function._propagateToListeners (http://localhost:50501/dart_sdk.js:34303:17) at _Future.new .[_completeWithValue] (http://localhost:50501/dart_sdk.js:34151:23) 在 async._AsyncCallbackEntry.new.callback (http://loc alhost:50501/dart_sdk.js:34172:35) 在 Object._microtaskLoop (http://localhost:50501/dart_sdk.js:38778:13) 在 _startMicrotaskLoop (http://localhost:50501/dart_sdk.js:38788) 13) 在 http://localhost:50501/dart_sdk.js:34519:9

下面是模型类的代码：

class WeatherAppDetails {
  City? city;
  String? cod;
  double? message;
  int? cnt;
  List<ListDetails>? list;

  WeatherAppDetails(
      {required this.city,
      required this.cod,
      required this.message,
      required this.cnt,
      required this.list});

  WeatherAppDetails.fromJson(Map<String, dynamic> json) {
    final cod = json['cod'];
    final message = json['message'];
    final cnt = json['cnt'];
    if (json['list'] != null) {
      list = <ListDetails>[];
      json['list'].forEach((v) {
        list!.add(ListDetails.fromJson(v));
      });
    }
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    if (city != null) {
      data['city'] = city!.toJson();
    }
    data['cod'] = cod;
    data['message'] = message;
    data['cnt'] = cnt;
    if (list != null) {
      data['list'] = list!.map((v) => v.toJson()).toList();
    }
    return data;
  }
}

class City {
  int? id;
  String? name;
  Coord? coord;
  String? country;
  int? population;
  int? timezone;

  City(
      {required this.id,
      required this.name,
      required this.coord,
      required this.country,
      required this.population,
      required this.timezone});

  City.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    name = json['name'];
    coord = (json['coord'] != null ? Coord.fromJson(json['coord']) : null)!;
    country = json['country'];
    population = json['population'];
    timezone = json['timezone'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    data['id'] = id;
    data['name'] = name;
    if (coord != null) {
      data['coord'] = coord!.toJson();
    }
    data['country'] = country;
    data['population'] = population;
    data['timezone'] = timezone;
    return data;
  }
}

class Coord {
  double? lon;
  double? lat;

  Coord({required this.lon, required this.lat});

  Coord.fromJson(Map<String, dynamic> json) {
    lon = json['lon'];
    lat = json['lat'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    data['lon'] = lon;
    data['lat'] = lat;
    return data;
  }
}

class ListDetails {
  int? dt;
  int? sunrise;
  int? sunset;
  Temp? temp;
  FeelsLike? feelsLike;
  int? pressure;
  int? humidity;
  List<WeatherDetails>? weather;
  double? speed;
  int? deg;
  double? gust;
  int? clouds;
  double? pop;
  double? rain;

  ListDetails(
      {required this.dt,
      required this.sunrise,
      required this.sunset,
      required this.temp,
      required this.feelsLike,
      required this.pressure,
      required this.humidity,
      required this.weather,
      required this.speed,
      required this.deg,
      required this.gust,
      required this.clouds,
      required this.pop,
      required this.rain});

  ListDetails.fromJson(Map<String, dynamic> json) {
    dt = json['dt'];
    sunrise = json['sunrise'];
    sunset = json['sunset'];
    temp = json['temp'] != null ? Temp.fromJson(json['temp']) : null;
    feelsLike = json['feels_like'] != null
        ? FeelsLike.fromJson(json['feels_like'])
        : null;
    pressure = json['pressure'];
    humidity = json['humidity'];
    if (json['weather'] != null) {
      weather = <WeatherDetails>[];
      json['weather'].forEach((v) {
        weather!.add(WeatherDetails.fromJson(v));
      });
    }
    speed = json['speed'];
    deg = json['deg'];
    gust = json['gust'];
    clouds = json['clouds'];
    pop = json['pop'];
    rain = json['rain'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    data['dt'] = dt;
    data['sunrise'] = sunrise;
    data['sunset'] = sunset;
    if (temp != null) {
      data['temp'] = temp!.toJson();
    }
    if (feelsLike != null) {
      data['feels_like'] = feelsLike!.toJson();
    }
    data['pressure'] = pressure;
    data['humidity'] = humidity;
    if (weather != null) {
      data['weather'] = weather!.map((v) => v.toJson()).toList();
    }
    data['speed'] = speed;
    data['deg'] = deg;
    data['gust'] = gust;
    data['clouds'] = clouds;
    data['pop'] = pop;
    data['rain'] = rain;
    return data;
  }
}

class Temp {
  double? day;
  double? min;
  double? max;
  double? night;
  double? eve;
  double? morn;

  Temp(
      {required this.day,
      required this.min,
      required this.max,
      required this.night,
      required this.eve,
      required this.morn});

  Temp.fromJson(Map<String, dynamic> json) {
    day = json['day'];
    min = json['min'];
    max = json['max'];
    night = json['night'];
    eve = json['eve'];
    morn = json['morn'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    data['day'] = day;
    data['min'] = min;
    data['max'] = max;
    data['night'] = night;
    data['eve'] = eve;
    data['morn'] = morn;
    return data;
  }
}

class FeelsLike {
  double? day;
  double? night;
  double? eve;
  double? morn;

  FeelsLike(
      {required this.day,
      required this.night,
      required this.eve,
      required this.morn});

  FeelsLike.fromJson(Map<String, dynamic> json) {
    day = json['day'];
    night = json['night'];
    eve = json['eve'];
    morn = json['morn'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    data['day'] = day;
    data['night'] = night;
    data['eve'] = eve;
    data['morn'] = morn;
    return data;
  }
}

class WeatherDetails {
  int? id;
  String? main;
  String? description;
  String? icon;

  WeatherDetails(
      {required this.id,
      required this.main,
      required this.description,
      required this.icon});

  WeatherDetails.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    main = json['main'];
    description = json['description'];
    icon = json['icon'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = <String, dynamic>{};
    data['id'] = id;
    data['main'] = main;
    data['description'] = description;
    data['icon'] = icon;
    return data;
  }
}

下面是网络类的代码：

class DataService {
  Future<WeatherAppDetails> getWeather(String name) async {
    final queryParameters = {
      'q': name,
      'appid': '3c044b7295d2df14f8bee74c19d4b96f',
      'units': 'imperial',
      'cnt': '7'
    };
    final uri = Uri.https(
        'api.openweathermap.org', '/data/2.5/forecast/daily', queryParameters);

    final response = await http.get(uri);
    print(response.body);
    if (response.statusCode == 200) {
      return WeatherAppDetails.fromJson(jsonDecode(response.body));
    } else {
      throw Exception('Failed to get posts');
    }
  }
}

Answer 1

基本上 api.weather 告诉你“q”参数的给定值不存在，没有找到地理位置。

添加城市参数输入很有帮助

您在请求中输入的城市是错误的，这应该有效（示例）

https://api.openweathermap.org/data/2.5/forecast/daily?appid=3c044b7295d2df14f8bee74c19d4b96f&q=英国伦敦