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How to deserialize complex json in Flutter?

Time：08-01

I have such json from the OpenWeatherMapApi:

{
    "coord": {
        "lon": 73.9352,
        "lat": 40.7306
    },
    "weather": [
        {
            "id": 804,
            "main": "Clouds",
            "description": "overcast clouds",
            "icon": "04d"
        }
    ],
    "base": "stations",
    "main": {
        "temp": 287.27,
        "feels_like": 285.57,
        "temp_min": 287.27,
        "temp_max": 287.27,
        "pressure": 1008,
        "humidity": 32,
        "sea_level": 1008,
        "grnd_level": 695
    },
    "visibility": 10000,
    "wind": {
        "speed": 3.67,
        "deg": 289,
        "gust": 5.14
    },
    "clouds": {
        "all": 87
    },
    "dt": 1659340567,
    "sys": {
        "country": "KG",
        "sunrise": 1659312024,
        "sunset": 1659363640
    },
    "timezone": 21600,
    "id": 8145969,
    "name": "Kara-Kulja",
    "cod": 200
}

And I used enter image description here

when in comparison class Forecast doesn't have such error. In the clean android development with kotlin I have to declare all fields of this json and then I will be able to get it after getting some response. But in the Flutter I have to create separate models for each complex field or how it has to be? Because then I will need to declare in the Future my model class:

@RestApi(baseUrl: "https://api.openweathermap.org/data/2.5/")
abstract class ApiClient {
  factory ApiClient(Dio dio, {String baseUrl}) = _ApiClient;

  @GET("weather?lat={lat}&lon={lon}&appid={appid}")
  Future<ResponseData> getUsers(@Path("lat") String lat,
      @Path("lon") String lon, @Path("appid") String appid);
}

Maybe I did something wrong only because I'm very new in Flutter and in this mobile development.

update

working with the result of deserialization:

@JsonSerializable()
class Forecast {
  List<WeatherModel> weather;

  Forecast({required this.weather});

  factory Forecast.fromJson(Map<String, dynamic> json) =>
      _$ForecastFromJson(json);

  Map<String, dynamic> toJson() => _$ForecastToJson(this);
}

@JsonSerializable()
class ResponseData {
  int code;
  dynamic meta;
  List<dynamic> data;

  ResponseData({required this.code, this.meta, required this.data});

  factory ResponseData.fromJson(Map<String, dynamic> json) =>
      _$ResponseDataFromJson(json);

  Map<String, dynamic> toJson() => _$ResponseDataToJson(this);
}

then I use ResponseData in the api call class.

CodePudding user response：

You can use your data like this

class WeatherModel {
  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;

  WeatherModel(
      {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});

  WeatherModel.fromJson(Map<String, dynamic> json) {
    coord = json['coord'] != null ? new Coord.fromJson(json['coord']) : null;
    if (json['weather'] != null) {
      weather = <Weather>[];
      json['weather'].forEach((v) {
        weather!.add(new Weather.fromJson(v));
      });
    }
    base = json['base'];
    main = json['main'] != null ? new Main.fromJson(json['main']) : null;
    visibility = json['visibility'];
    wind = json['wind'] != null ? new Wind.fromJson(json['wind']) : null;
    clouds =
        json['clouds'] != null ? new Clouds.fromJson(json['clouds']) : null;
    dt = json['dt'];
    sys = json['sys'] != null ? new Sys.fromJson(json['sys']) : null;
    timezone = json['timezone'];
    id = json['id'];
    name = json['name'];
    cod = json['cod'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    if (this.coord != null) {
      data['coord'] = this.coord!.toJson();
    }
    if (this.weather != null) {
      data['weather'] = this.weather!.map((v) => v.toJson()).toList();
    }
    data['base'] = this.base;
    if (this.main != null) {
      data['main'] = this.main!.toJson();
    }
    data['visibility'] = this.visibility;
    if (this.wind != null) {
      data['wind'] = this.wind!.toJson();
    }
    if (this.clouds != null) {
      data['clouds'] = this.clouds!.toJson();
    }
    data['dt'] = this.dt;
    if (this.sys != null) {
      data['sys'] = this.sys!.toJson();
    }
    data['timezone'] = this.timezone;
    data['id'] = this.id;
    data['name'] = this.name;
    data['cod'] = this.cod;
    return data;
  }
}

class Coord {
  double? lon;
  double? lat;

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

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

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

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

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

  Weather.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 = new Map<String, dynamic>();
    data['id'] = this.id;
    data['main'] = this.main;
    data['description'] = this.description;
    data['icon'] = this.icon;
    return data;
  }
}

class Main {
  double? temp;
  double? feelsLike;
  double? tempMin;
  double? tempMax;
  int? pressure;
  int? humidity;
  int? seaLevel;
  int? grndLevel;

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

  Main.fromJson(Map<String, dynamic> json) {
    temp = json['temp'];
    feelsLike = json['feels_like'];
    tempMin = json['temp_min'];
    tempMax = json['temp_max'];
    pressure = json['pressure'];
    humidity = json['humidity'];
    seaLevel = json['sea_level'];
    grndLevel = json['grnd_level'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['temp'] = this.temp;
    data['feels_like'] = this.feelsLike;
    data['temp_min'] = this.tempMin;
    data['temp_max'] = this.tempMax;
    data['pressure'] = this.pressure;
    data['humidity'] = this.humidity;
    data['sea_level'] = this.seaLevel;
    data['grnd_level'] = this.grndLevel;
    return data;
  }
}

class Wind {
  double? speed;
  int? deg;
  double? gust;

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

  Wind.fromJson(Map<String, dynamic> json) {
    speed = json['speed'];
    deg = json['deg'];
    gust = json['gust'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['speed'] = this.speed;
    data['deg'] = this.deg;
    data['gust'] = this.gust;
    return data;
  }
}

class Clouds {
  int? all;

  Clouds({this.all});

  Clouds.fromJson(Map<String, dynamic> json) {
    all = json['all'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['all'] = this.all;
    return data;
  }
}

class Sys {
  String? country;
  int? sunrise;
  int? sunset;

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

  Sys.fromJson(Map<String, dynamic> json) {
    country = json['country'];
    sunrise = json['sunrise'];
    sunset = json['sunset'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['country'] = this.country;
    data['sunrise'] = this.sunrise;
    data['sunset'] = this.sunset;
    return data;
  }
}

And if you make it using factory Constructor you can use

// To parse this JSON data, do
//
//     final weatherModel = weatherModelFromJson(jsonString);

import 'dart:convert';

WeatherModel weatherModelFromJson(String str) => WeatherModel.fromJson(json.decode(str));

String weatherModelToJson(WeatherModel data) => json.encode(data.toJson());

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

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

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

    int all;

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

    Map<String, dynamic> toJson() => {
        "all": all,
    };
}

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

    double lon;
    double lat;

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

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

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

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

    factory Main.fromJson(Map<String, dynamic> json) => Main(
        temp: json["temp"].toDouble(),
        feelsLike: json["feels_like"].toDouble(),
        tempMin: json["temp_min"].toDouble(),
        tempMax: json["temp_max"].toDouble(),
        pressure: json["pressure"],
        humidity: json["humidity"],
        seaLevel: json["sea_level"],
        grndLevel: json["grnd_level"],
    );

    Map<String, dynamic> toJson() => {
        "temp": temp,
        "feels_like": feelsLike,
        "temp_min": tempMin,
        "temp_max": tempMax,
        "pressure": pressure,
        "humidity": humidity,
        "sea_level": seaLevel,
        "grnd_level": grndLevel,
    };
}

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

    String country;
    int sunrise;
    int sunset;

    factory Sys.fromJson(Map<String, dynamic> json) => Sys(
        country: json["country"],
        sunrise: json["sunrise"],
        sunset: json["sunset"],
    );

    Map<String, dynamic> toJson() => {
        "country": country,
        "sunrise": sunrise,
        "sunset": sunset,
    };
}

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

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

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

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

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

    double speed;
    int deg;
    double gust;

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

    Map<String, dynamic> toJson() => {
        "speed": speed,
        "deg": deg,
        "gust": gust,
    };
}

CodePudding user response：

You're missing ";" in this code line. This is why you're having that error.

weatherModel(
      {required this.id, required this.main, required this.description, required this.icon});  //here

Additional advice: It's recommended to have Uppercase starting name when it comes to models

weatherModel-> WeatherModel

Page link：https//www.codepudding.com/Softwareengineering/495484.html

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