Flutter Future builder not dispalying ListView - flutter

Question

I am trying to loop through weather forcast form OpenWeather API.
List view is not rendered. Only loading indicator is rendered. "list" is array where i want to fetch data and display in ListView. I think there is someting wrong with model mapping. Thank you
{
"list": [
{
"dt": 1566518400,
"main": {
"temp": 14.68,
"temp_min": 14.25,
"temp_max": 14.68,
"pressure": 1029.5,
"sea_level": 1029.5,
"grnd_level": 1018.5,
"humidity": 74,
"temp_kf": 0.43
},
"weather": [
{
"id": 801,
"main": "Clouds",
"description": "few clouds",
"icon": "02n"
}
],
"clouds": {
"all": 16
},
"wind": {
"speed": 2.42,
"deg": 93.981
},
"sys": {
"pod": "n"
},
"dt_txt": "2019-08-23 00:00:00"
},
Function to fetch forcast
Future<List<Forcast>> _fetchUsers() async {
http.Response response = await http.get(
'http://api.openweathermap.org/data/2.5/forecast?q=warsaw&units=metric&appid=');
if (response.statusCode == 200) {
final data = json.decode(response.body);
List<Forcast> list = data['list'].map<Forcast>((json) {
return Forcast.fromJson(json);
}).toList();
return list;
} else {
throw Exception('Failed to load internet');
}
}
Future builder
child: SizedBox(
height: 400.0,
child: FutureBuilder<List>(
future: _fetchUsers(),
builder: (context, snapshot) {
if (!snapshot.hasData)
return Center(child: CircularProgressIndicator());
return ListView(
children: snapshot.data
.map((user) => ListTile(
title: Text(user.dt),
subtitle: Text(user.temp),
))
.toList(),
);
},
),
),
Forcastt model
class Forcast {
int id;
String temp;
Forcast({
this.id,
this.temp,
});
factory Forcast.fromJson(Map<String, dynamic> json) {
print(json);
return Forcast(
id: json['dt'],
temp: json['main'].temp,
);
}
}

Answer 1

You can put your full json string to https://app.quicktype.io/
and you will get correct model
because json string you post in question is invalid
so I use json from demo json of https://samples.openweathermap.org/data/2.5/forecast?q=M%C3%BCnchen,DE&appid=b6907d289e10d714a6e88b30761fae22
bleow is demo Forcast structure from sample json
// To parse this JSON data, do
//
// final forcast = forcastFromJson(jsonString);
import 'dart:convert';
Forcast forcastFromJson(String str) => Forcast.fromJson(json.decode(str));
String forcastToJson(Forcast data) => json.encode(data.toJson());
class Forcast {
String cod;
double message;
int cnt;
List<ListElement> list;
City city;
Forcast({
this.cod,
this.message,
this.cnt,
this.list,
this.city,
});
factory Forcast.fromJson(Map<String, dynamic> json) => new Forcast(
cod: json["cod"],
message: json["message"].toDouble(),
cnt: json["cnt"],
list: new List<ListElement>.from(json["list"].map((x) => ListElement.fromJson(x))),
city: City.fromJson(json["city"]),
);
Map<String, dynamic> toJson() => {
"cod": cod,
"message": message,
"cnt": cnt,
"list": new List<dynamic>.from(list.map((x) => x.toJson())),
"city": city.toJson(),
};
}
class City {
int id;
String name;
Coord coord;
String country;
City({
this.id,
this.name,
this.coord,
this.country,
});
factory City.fromJson(Map<String, dynamic> json) => new City(
id: json["id"],
name: json["name"],
coord: Coord.fromJson(json["coord"]),
country: json["country"],
);
Map<String, dynamic> toJson() => {
"id": id,
"name": name,
"coord": coord.toJson(),
"country": country,
};
}
class Coord {
double lat;
double lon;
Coord({
this.lat,
this.lon,
});
factory Coord.fromJson(Map<String, dynamic> json) => new Coord(
lat: json["lat"].toDouble(),
lon: json["lon"].toDouble(),
);
Map<String, dynamic> toJson() => {
"lat": lat,
"lon": lon,
};
}
class ListElement {
int dt;
MainClass main;
List<Weather> weather;
Clouds clouds;
Wind wind;
Sys sys;
DateTime dtTxt;
Rain rain;
Rain snow;
ListElement({
this.dt,
this.main,
this.weather,
this.clouds,
this.wind,
this.sys,
this.dtTxt,
this.rain,
this.snow,
});
factory ListElement.fromJson(Map<String, dynamic> json) => new ListElement(
dt: json["dt"],
main: MainClass.fromJson(json["main"]),
weather: new List<Weather>.from(json["weather"].map((x) => Weather.fromJson(x))),
clouds: Clouds.fromJson(json["clouds"]),
wind: Wind.fromJson(json["wind"]),
sys: Sys.fromJson(json["sys"]),
dtTxt: DateTime.parse(json["dt_txt"]),
rain: json["rain"] == null ? null : Rain.fromJson(json["rain"]),
snow: json["snow"] == null ? null : Rain.fromJson(json["snow"]),
);
Map<String, dynamic> toJson() => {
"dt": dt,
"main": main.toJson(),
"weather": new List<dynamic>.from(weather.map((x) => x.toJson())),
"clouds": clouds.toJson(),
"wind": wind.toJson(),
"sys": sys.toJson(),
"dt_txt": dtTxt.toIso8601String(),
"rain": rain == null ? null : rain.toJson(),
"snow": snow == null ? null : snow.toJson(),
};
}
class Clouds {
int all;
Clouds({
this.all,
});
factory Clouds.fromJson(Map<String, dynamic> json) => new Clouds(
all: json["all"],
);
Map<String, dynamic> toJson() => {
"all": all,
};
}
class MainClass {
double temp;
double tempMin;
double tempMax;
double pressure;
double seaLevel;
double grndLevel;
int humidity;
double tempKf;
MainClass({
this.temp,
this.tempMin,
this.tempMax,
this.pressure,
this.seaLevel,
this.grndLevel,
this.humidity,
this.tempKf,
});
factory MainClass.fromJson(Map<String, dynamic> json) => new MainClass(
temp: json["temp"].toDouble(),
tempMin: json["temp_min"].toDouble(),
tempMax: json["temp_max"].toDouble(),
pressure: json["pressure"].toDouble(),
seaLevel: json["sea_level"].toDouble(),
grndLevel: json["grnd_level"].toDouble(),
humidity: json["humidity"],
tempKf: json["temp_kf"].toDouble(),
);
Map<String, dynamic> toJson() => {
"temp": temp,
"temp_min": tempMin,
"temp_max": tempMax,
"pressure": pressure,
"sea_level": seaLevel,
"grnd_level": grndLevel,
"humidity": humidity,
"temp_kf": tempKf,
};
}
class Rain {
double the3H;
Rain({
this.the3H,
});
factory Rain.fromJson(Map<String, dynamic> json) => new Rain(
the3H: json["3h"] == null ? null : json["3h"].toDouble(),
);
Map<String, dynamic> toJson() => {
"3h": the3H == null ? null : the3H,
};
}
class Sys {
Pod pod;
Sys({
this.pod,
});
factory Sys.fromJson(Map<String, dynamic> json) => new Sys(
pod: podValues.map[json["pod"]],
);
Map<String, dynamic> toJson() => {
"pod": podValues.reverse[pod],
};
}
enum Pod { D, N }
final podValues = new EnumValues({
"d": Pod.D,
"n": Pod.N
});
class Weather {
int id;
MainEnum main;
Description description;
String icon;
Weather({
this.id,
this.main,
this.description,
this.icon,
});
factory Weather.fromJson(Map<String, dynamic> json) => new Weather(
id: json["id"],
main: mainEnumValues.map[json["main"]],
description: descriptionValues.map[json["description"]],
icon: json["icon"],
);
Map<String, dynamic> toJson() => {
"id": id,
"main": mainEnumValues.reverse[main],
"description": descriptionValues.reverse[description],
"icon": icon,
};
}
enum Description { CLEAR_SKY, BROKEN_CLOUDS, LIGHT_RAIN, MODERATE_RAIN, FEW_CLOUDS }
final descriptionValues = new EnumValues({
"broken clouds": Description.BROKEN_CLOUDS,
"clear sky": Description.CLEAR_SKY,
"few clouds": Description.FEW_CLOUDS,
"light rain": Description.LIGHT_RAIN,
"moderate rain": Description.MODERATE_RAIN
});
enum MainEnum { CLEAR, CLOUDS, RAIN }
final mainEnumValues = new EnumValues({
"Clear": MainEnum.CLEAR,
"Clouds": MainEnum.CLOUDS,
"Rain": MainEnum.RAIN
});
class Wind {
double speed;
double deg;
Wind({
this.speed,
this.deg,
});
factory Wind.fromJson(Map<String, dynamic> json) => new Wind(
speed: json["speed"].toDouble(),
deg: json["deg"].toDouble(),
);
Map<String, dynamic> toJson() => {
"speed": speed,
"deg": deg,
};
}
class EnumValues<T> {
Map<String, T> map;
Map<T, String> reverseMap;
EnumValues(this.map);
Map<T, String> get reverse {
if (reverseMap == null) {
reverseMap = map.map((k, v) => new MapEntry(v, k));
}
return reverseMap;
}
}