在 Flutter 中发出 API 请求时映射值的问题

Question

我正在向 OpenWeather API 发出一个简单的获取请求，但在调试时我意识到尽管我收到了响应，但主体值的映射过程并未完成。调试器没有进入我的数据模型，因此没有映射任何东西，我无法将数据保存到我的“weatherList”列表中。

这是我的获取请求：

  fetchWeatherData(urlw) async {
    final responsew = await client.get(Uri.parse(urlw));
    if (responsew.statusCode == 200) {
      weatherList = (json.decode(responsew.body) as List)
          .map((data) => weatherAPI.fromJson(data))
          .toList();
    } else {
      throw Exception('Failed to load data');
    }
  }

这里是 response.body 值：

{"coord":{"lon":2.1734,"lat":41.3851},"weather":[{"id":800,"main":"Clear","description":"clear sky","icon":"01d"}],"base":"stations","main":{"temp":21.23,"feels_like":20.56,"temp_min":18.16,"temp_max":26.64,"pressure":1016,"humidity":44},"visibility":10000,"wind":{"speed":7.72,"deg":80},"clouds":{"all":0},"dt":1649941625,"sys":{"type":2,"id":2003688,"country":"ES","sunrise":1649913201,"sunset":1649960967},"timezone":7200,"id":6544100,"name":"Eixample","cod":200}

这是我的数据模型：

class weatherAPI {
  Coord? _coord;
  List<Weather>? _weather;
  String? _base;
  MainWeather? _main;
  int? _visibility;
  Wind? _wind;
  Clouds? _clouds;
  int? _dt;
  Sys? _sys;
  int? _timezone;
  int? _id;
  String? _name;
  int? _cod;

  weatherAPI(
      {Coord? coord,
      List<Weather>? weather,
      String? base,
      MainWeather? main,
      int? visibility,
      Wind? wind,
      Clouds? clouds,
      int? dt,
      Sys? sys,
      int? timezone,
      int? id,
      String? name,
      int? cod}) {
    if (coord != null) {
      this._coord = coord;
    }
    if (weather != null) {
      this._weather = weather;
    }
    if (base != null) {
      this._base = base;
    }
    if (main != null) {
      this._main = main;
    }
    if (visibility != null) {
      this._visibility = visibility;
    }
    if (wind != null) {
      this._wind = wind;
    }
    if (clouds != null) {
      this._clouds = clouds;
    }
    if (dt != null) {
      this._dt = dt;
    }
    if (sys != null) {
      this._sys = sys;
    }
    if (timezone != null) {
      this._timezone = timezone;
    }
    if (id != null) {
      this._id = id;
    }
    if (name != null) {
      this._name = name;
    }
    if (cod != null) {
      this._cod = cod;
    }
  }

  Coord? get coord => _coord;
  set coord(Coord? coord) => _coord = coord;
  List<Weather>? get weather => _weather;
  set weather(List<Weather>? weather) => _weather = weather;
  String? get base => _base;
  set base(String? base) => _base = base;
  MainWeather? get main => _main;
  set main(MainWeather? main) => _main = main;
  int? get visibility => _visibility;
  set visibility(int? visibility) => _visibility = visibility;
  Wind? get wind => _wind;
  set wind(Wind? wind) => _wind = wind;
  Clouds? get clouds => _clouds;
  set clouds(Clouds? clouds) => _clouds = clouds;
  int? get dt => _dt;
  set dt(int? dt) => _dt = dt;
  Sys? get sys => _sys;
  set sys(Sys? sys) => _sys = sys;
  int? get timezone => _timezone;
  set timezone(int? timezone) => _timezone = timezone;
  int? get id => _id;
  set id(int? id) => _id = id;
  String? get name => _name;
  set name(String? name) => _name = name;
  int? get cod => _cod;
  set cod(int? cod) => _cod = cod;

  factory weatherAPI.fromJson(Map<String, dynamic> json) {
    return weatherAPI(
    coord: json['coord'] != null ?  Coord.fromJson(json['coord']) : null,

    //weather: json['weather'] != null ? Weather.fromJson(json['weather']) : null,

    base : json['base'],
    main : json['main'] != null ?  MainWeather.fromJson(json['main']) : null,
    visibility : json['visibility'],
    wind : json['wind'] != null ?  Wind.fromJson(json['wind']) : null,
    clouds : json['clouds'] != null ?  Clouds.fromJson(json['clouds']) : null,
    dt : json['dt'],
    sys : json['sys'] != null ?  Sys.fromJson(json['sys']) : null,
    timezone : json['timezone'],
    id : json['id'],
    name : json['name'],
    cod : json['cod']
    );
    }

我有解析错误吗？？

Answer 1

试试这个模型一次

// To parse this JSON data, do


import 'dart:convert';

class WeatherAPI {
WeatherAPI({
    this.coord,
    this.weather,
    this.base,
    this.main,
    this.visibility,
    this.wind,
    this.clouds,
    this.dt,
    this.sys,
    this.timezone,
    this.id,
    this.name,
    this.cod,
});

Coord coord;
List<Weather> weather;
String base;
Main main;
int visibility;
Wind wind;
Clouds clouds;
int dt;
Sys sys;
int timezone;
int id;
String name;
int cod;

factory WeatherAPI.fromJson(String str) => WeatherAPI.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory WeatherAPI.fromMap(Map<String, dynamic> json) => WeatherAPI(
    coord: json["coord"] == null ? null : Coord.fromMap(json["coord"]),
    weather: json["weather"] == null ? null : List<Weather>.from(json["weather"].map((x) => Weather.fromMap(x))),
    base: json["base"] == null ? null : json["base"],
    main: json["main"] == null ? null : Main.fromMap(json["main"]),
    visibility: json["visibility"] == null ? null : json["visibility"],
    wind: json["wind"] == null ? null : Wind.fromMap(json["wind"]),
    clouds: json["clouds"] == null ? null : Clouds.fromMap(json["clouds"]),
    dt: json["dt"] == null ? null : json["dt"],
    sys: json["sys"] == null ? null : Sys.fromMap(json["sys"]),
    timezone: json["timezone"] == null ? null : json["timezone"],
    id: json["id"] == null ? null : json["id"],
    name: json["name"] == null ? null : json["name"],
    cod: json["cod"] == null ? null : json["cod"],
);

Map<String, dynamic> toMap() => {
    "coord": coord == null ? null : coord.toMap(),
    "weather": weather == null ? null : List<dynamic>.from(weather.map((x) => x.toMap())),
    "base": base == null ? null : base,
    "main": main == null ? null : main.toMap(),
    "visibility": visibility == null ? null : visibility,
    "wind": wind == null ? null : wind.toMap(),
    "clouds": clouds == null ? null : clouds.toMap(),
    "dt": dt == null ? null : dt,
    "sys": sys == null ? null : sys.toMap(),
    "timezone": timezone == null ? null : timezone,
    "id": id == null ? null : id,
    "name": name == null ? null : name,
    "cod": cod == null ? null : cod,
 };
 }

class Clouds {
Clouds({
    this.all,
});

int all;

factory Clouds.fromJson(String str) => Clouds.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory Clouds.fromMap(Map<String, dynamic> json) => Clouds(
    all: json["all"] == null ? null : json["all"],
);

Map<String, dynamic> toMap() => {
    "all": all == null ? null : all,
};
}

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

double lon;
double lat;

factory Coord.fromJson(String str) => Coord.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory Coord.fromMap(Map<String, dynamic> json) => Coord(
    lon: json["lon"] == null ? null : json["lon"].toDouble(),
    lat: json["lat"] == null ? null : json["lat"].toDouble(),
);

Map<String, dynamic> toMap() => {
    "lon": lon == null ? null : lon,
    "lat": lat == null ? null : lat,
};
}

class Main {
Main({
    this.temp,
    this.feelsLike,
    this.tempMin,
    this.tempMax,
    this.pressure,
    this.humidity,
});

double temp;
double feelsLike;
double tempMin;
double tempMax;
int pressure;
int humidity;

factory Main.fromJson(String str) => Main.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory Main.fromMap(Map<String, dynamic> json) => Main(
    temp: json["temp"] == null ? null : json["temp"].toDouble(),
    feelsLike: json["feels_like"] == null ? null : json["feels_like"].toDouble(),
    tempMin: json["temp_min"] == null ? null : json["temp_min"].toDouble(),
    tempMax: json["temp_max"] == null ? null : json["temp_max"].toDouble(),
    pressure: json["pressure"] == null ? null : json["pressure"],
    humidity: json["humidity"] == null ? null : json["humidity"],
);

Map<String, dynamic> toMap() => {
    "temp": temp == null ? null : temp,
    "feels_like": feelsLike == null ? null : feelsLike,
    "temp_min": tempMin == null ? null : tempMin,
    "temp_max": tempMax == null ? null : tempMax,
    "pressure": pressure == null ? null : pressure,
    "humidity": humidity == null ? null : humidity,
};
}

class Sys {
Sys({
    this.type,
    this.id,
    this.country,
    this.sunrise,
    this.sunset,
});

int type;
int id;
String country;
int sunrise;
int sunset;

factory Sys.fromJson(String str) => Sys.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory Sys.fromMap(Map<String, dynamic> json) => Sys(
    type: json["type"] == null ? null : json["type"],
    id: json["id"] == null ? null : json["id"],
    country: json["country"] == null ? null : json["country"],
    sunrise: json["sunrise"] == null ? null : json["sunrise"],
    sunset: json["sunset"] == null ? null : json["sunset"],
);

Map<String, dynamic> toMap() => {
    "type": type == null ? null : type,
    "id": id == null ? null : id,
    "country": country == null ? null : country,
    "sunrise": sunrise == null ? null : sunrise,
    "sunset": sunset == null ? null : sunset,
};
}

class Weather {
Weather({
    this.id,
    this.main,
    this.description,
    this.icon,
});

int id;
String main;
String description;
String icon;

factory Weather.fromJson(String str) => Weather.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory Weather.fromMap(Map<String, dynamic> json) => Weather(
    id: json["id"] == null ? null : json["id"],
    main: json["main"] == null ? null : json["main"],
    description: json["description"] == null ? null : json["description"],
    icon: json["icon"] == null ? null : json["icon"],
);

Map<String, dynamic> toMap() => {
    "id": id == null ? null : id,
    "main": main == null ? null : main,
    "description": description == null ? null : description,
    "icon": icon == null ? null : icon,
};
}

class Wind {
Wind({
    this.speed,
    this.deg,
});

double speed;
int deg;

factory Wind.fromJson(String str) => Wind.fromMap(json.decode(str));

String toJson() => json.encode(toMap());

factory Wind.fromMap(Map<String, dynamic> json) => Wind(
    speed: json["speed"] == null ? null : json["speed"].toDouble(),
    deg: json["deg"] == null ? null : json["deg"],
);

Map<String, dynamic> toMap() => {
    "speed": speed == null ? null : speed,
    "deg": deg == null ? null : deg,
};

}

在 Flutter 中发出 API 请求时映射值的问题

Problem in mapping values while making API requests in Flutter

api

https

dart

flutter