Parse Json in Dart/Flutter to Entity/Model - json

Question

Greetings
I am having this problem converting the following json to TodayWeather Entity:
How can I use the named constructor TodayHours?
I've been looking for a solution for this issue for a few days now, but I haven't found much, please guide me.
json:
{
"days": [
{
"datetime": "2023-01-05",
"datetimeEpoch": 1672864200,
"tempmax": 8.8,
"tempmin": 2.3,
"temp": 5.3,
"windspeed": 8.6,
"winddir": 223.9,
"visibility": 19.7,
"sunrise": "06:43:43",
"sunset": "16:30:24",
"conditions": "Snow, Rain, Overcast",
"hours": [
{
"datetime": "00:00:00",
"datetimeEpoch": 1672864200,
"temp": 4.4,
"humidity": 27.65,
"windspeed": 6.5,
"winddir": 249.2,
"visibility": 24.1,
"conditions": "Partially cloudy"
},
{
"datetime": "01:00:00",
"datetimeEpoch": 1672864200,
"temp": 4.4,
"humidity": 27.65,
"windspeed": 6.5,
"winddir": 249.2,
"visibility": 24.1,
"conditions": "Partially cloudy"
}
]
}
]
}
and my TodayWeather Entitiy is :
class TodayWeather {
final String datetime;
final num dateEpoch;
final String conditions;
final num tempMax;
final num tempMin;
final num windDir;
final num windSpeed;
final String sunRise;
final String sunSet;
final num humidity;
final num visibility;
final List<TodayHourse> hours;
TodayWeather.fromJson(Map<String, dynamic> json)
: datetime = json['days'][0]['datetime'],
dateEpoch = json['days'][0]['datetimeEpoch'],
conditions = json['days'][0]['conditions'],
tempMax = json['days'][0]['tempmax'],
tempMin = json['days'][0]['tempmin'],
windDir = json['days'][0]['winddir'],
windSpeed = json['days'][0]['windspeed'],
sunRise = json['days'][0]['sunrise'],
sunSet = json['days'][0]['sunset'],
humidity = json['days'][0]['humidity'],
visibility = json['days'][0]['visibility'],
hours = List<TodayHourse>.from(
json['days'][0]['hours'].map((x) => x.toJson())).toList();
}
and my TodayHours Entitiy is :
class TodayHourse {
final String datetime;
final num dateEpoch;
final String conditions;
final num temp;
final num windDir;
final num windSpeed;
final num humidity;
final num visibility;
Map<String, dynamic> toJson() => {
'datetime': datetime,
'datetimeEpoch': dateEpoch,
'conditions': conditions,
'temp': temp,
'winddir': windDir,
'windspeed': windSpeed,
'humidity': humidity,
'visibility': visibility
};
TodayHourse.fromJson(Map<String, dynamic> json)
: datetime = json['days'][0]['datetime'],
dateEpoch = json['days'][0]['datetimeEpoch'],
conditions = json['days'][0]['conditions'],
temp = json['days'][0]['temp'],
windDir = json['days'][0]['winddir'],
windSpeed = json['days'][0]['windspeed'],
humidity = json['days'][0]['humidity'],
visibility = json['days'][0]['visibility'];
}
this method is parsing Json to TodayWeather:
#override
Future<TodayWeather> getTodayWeather() async {
final response = await httpClient.get(
'36.31559%2C59.56796/today?unitGroup=metric&key=Key&contentType=json');
validResponse(response);
return TodayWeather.fromJson(response.data);
}

Answer 1

First change your TodayHourse.fromJson to this:
TodayHourse.fromJson(Map<String, dynamic> json)
: datetime = json['datetime'],
dateEpoch = json['datetimeEpoch'],
conditions = json['conditions'],
temp = json['temp'],
windDir = json['winddir'],
windSpeed = json['windspeed'],
humidity = json['humidity'],
visibility = json['visibility'];
your hours is list of Map and you don't need to use json['days'][0]. Then in your TodayWeather.fromJson, change hours to this:
hours = (json['days'][0]['hours'] as List).map((x) => TodayHourse.fromJson(x)).toList();
you are using wrong function instead of toJson, you need to call TodayHourse.fromJson(x).

Answer 2

Try to use this model:
class TodayWeather {
TodayWeather({required this.days});
final List<Day> days;
factory TodayWeather.fromJson(Map<String, dynamic> json) => TodayWeather(
days: List<Day>.from(json["days"].map((x) => Day.fromJson(x))),
);
}
class Day {
Day({
required this.datetime,
required this.datetimeEpoch,
required this.tempmax,
required this.tempmin,
required this.temp,
required this.windspeed,
required this.winddir,
required this.visibility,
required this.sunrise,
required this.sunset,
required this.conditions,
required this.hours,
});
final DateTime datetime;
final int datetimeEpoch;
final double tempmax, tempmin, temp, windspeed, winddir, visibility;
final String sunrise, sunset, conditions;
final List<Hour> hours;
factory Day.fromJson(Map<String, dynamic> json) => Day(
datetime: DateTime.parse(json["datetime"]),
datetimeEpoch: json["datetimeEpoch"],
tempmax: json["tempmax"].toDouble(),
tempmin: json["tempmin"].toDouble(),
temp: json["temp"].toDouble(),
windspeed: json["windspeed"].toDouble(),
winddir: json["winddir"].toDouble(),
visibility: json["visibility"].toDouble(),
sunrise: json["sunrise"],
sunset: json["sunset"],
conditions: json["conditions"],
hours: List<Hour>.from(json["hours"].map((x) => Hour.fromJson(x))),
);
}
class Hour {
Hour({
required this.datetime,
required this.datetimeEpoch,
required this.temp,
required this.humidity,
required this.windspeed,
required this.winddir,
required this.visibility,
required this.conditions,
});
final int datetimeEpoch;
final double temp, humidity, windspeed, winddir, visibility;
final String datetime, conditions;
factory Hour.fromJson(Map<String, dynamic> json) => Hour(
datetime: json["datetime"],
datetimeEpoch: json["datetimeEpoch"],
temp: json["temp"].toDouble(),
humidity: json["humidity"].toDouble(),
windspeed: json["windspeed"].toDouble(),
winddir: json["winddir"].toDouble(),
visibility: json["visibility"].toDouble(),
conditions: json["conditions"],
);
}

Answer 3

First of all for more clear way to parse JSON arrays you can create helper method in your models, I call it Model.fromJsonList
static List<WeatherDay> fromJsonList(dynamic jsonList) {
if (jsonList == null || jsonList.isEmpty) return [];
return (jsonList as List).map((e) => WeatherDay.fromJson(e)).toList();
}
So by this method you can parse array response very easy and clean for example:
Future<WeatherDay> fetchTodayWeather() async {
final response = await httpClient.get(
'36.31559%2C59.56796/today?unitGroup=metric&key=Key&contentType=json');
final List<WeatherDay> weatherDays = WeatherDay.fromJsonList(response.data["days"]);
return weatherDays.first;
}
Totally we have:
class WeatherDay {
WeatherDay( {
#required this.datetime,
#required this.hours,
});
final String datetime;
final List<WeatherHour> hours;
factory WeatherDay.fromJson(Map<String, dynamic> json) {
return WeatherDay(
datetime: json['datetime'] as String,
hours: WeatherHour.fromJsonList(json['hours']),
);
}
static List<WeatherDay> fromJsonList(dynamic jsonList) {
if (jsonList == null || jsonList.isEmpty) return [];
return (jsonList as List).map((e) => WeatherDay.fromJson(e)).toList();
}
}
class WeatherHour {
WeatherHour( {
#required this.dateEpoch,
#required this.conditions,
});
final num dateEpoch;
final String conditions;
factory WeatherHour.fromJson(Map<String, dynamic> json) {
return WeatherHour(
dateEpoch: json['datetimeEpoch'] as num,
conditions: json['conditions'] as String,
);
}
static List<WeatherHour> fromJsonList(dynamic jsonList) {
if (jsonList == null || jsonList.isEmpty) return [];
return (jsonList as List).map((e) => WeatherHour.fromJson(e)).toList();
}
}
Note: I didn't parse all variable, do it by yourself.