Flutter双嵌套json列表到Dart模型

Question

我正试图将这个json响应转换为dart模型，但我不知道如何解析"排名"；它是一个双嵌套列表。我现在尝试的东西不起作用(我想我应该访问更高列表中的第一个元素(：

StandingLeague.fromJson(Map<String, dynamic> json) {
id = json['id'];
name = json['name'];
country = json['country'];
logo = json['logo'];
flag = json['flag'];
season = json['season'];
if (json['standings'] != null) {
standings = <Standing>[];
json['standings'][0].forEach((v) { standings?.add(v); });
}
}

Json回应：

{
"league": {
"id": 39,
"name": "Premier League",
"country": "England",
"logo": "https://media.api-sports.io/football/leagues/39.png",
"flag": "https://media.api-sports.io/flags/gb.svg",
"season": 2022,
"standings": [
[
{
"rank": 1,
"team": {
"id": 42,
"name": "Arsenal",
"logo": "https://media.api-sports.io/football/teams/42.png"
},
"points": 18,
"goalsDiff": 10,
"group": "Premier League",
"form": "WLWWW",
"status": "same",
"description": "Promotion - Champions League (Group Stage)",
"all": {
"played": 7,
"win": 6,
"draw": 0,
"lose": 1,
"goals": {
"for": 17,
"against": 7
}
},
"home": {
"played": 3,
"win": 3,
"draw": 0,
"lose": 0,
"goals": {
"for": 8,
"against": 4
}
},
"away": {
"played": 4,
"win": 3,
"draw": 0,
"lose": 1,
"goals": {
"for": 9,
"against": 3
}
},
"update": "2022-09-18T00:00:00+00:00"
},
{
"rank": 2,
"team": {
"id": 50,
"name": "Manchester City",
"logo": "https://media.api-sports.io/football/teams/50.png"
},
"points": 17,
"goalsDiff": 17,
"group": "Premier League",
"form": "WDWWD",
"status": "same",
"description": "Promotion - Champions League (Group Stage)",
"all": {
"played": 7,
"win": 5,
"draw": 2,
"lose": 0,
"goals": {
"for": 23,
"against": 6
}
},
"home": {
"played": 3,
"win": 3,
"draw": 0,
"lose": 0,
"goals": {
"for": 14,
"against": 2
}
},
"away": {
"played": 4,
"win": 2,
"draw": 2,
"lose": 0,
"goals": {
"for": 9,
"against": 4
}
},
"update": "2022-09-18T00:00:00+00:00"
},
{
"rank": 3,
"team": {
"id": 47,
"name": "Tottenham",
"logo": "https://media.api-sports.io/football/teams/47.png"
},
"points": 17,
"goalsDiff": 11,
"group": "Premier League",
"form": "WWDWW",
"status": "same",
"description": "Promotion - Champions League (Group Stage)",
"all": {
"played": 7,
"win": 5,
"draw": 2,
"lose": 0,
"goals": {
"for": 18,
"against": 7
}
},
"home": {
"played": 4,
"win": 4,
"draw": 0,
"lose": 0,
"goals": {
"for": 13,
"against": 4
}
},
"away": {
"played": 3,
"win": 1,
"draw": 2,
"lose": 0,
"goals": {
"for": 5,
"against": 3
}
},
"update": "2022-09-18T00:00:00+00:00"
},
{
"rank": 4,
"team": {
"id": 51,
"name": "Brighton",
"logo": "https://media.api-sports.io/football/teams/51.png"
},
"points": 13,
"goalsDiff": 6,
"group": "Premier League",
"form": "WLWWD",
"status": "same",
"description": "Promotion - Champions League (Group Stage)",
"all": {
"played": 6,
"win": 4,
"draw": 1,
"lose": 1,
"goals": {
"for": 11,
"against": 5
}
},
"home": {
"played": 3,
"win": 2,
"draw": 1,
"lose": 0,
"goals": {
"for": 6,
"against": 2
}
},
"away": {
"played": 3,
"win": 2,
"draw": 0,
"lose": 1,
"goals": {
"for": 5,
"against": 3
}
},
"update": "2022-09-18T00:00:00+00:00"
},
{
"rank": 5,
"team": {
"id": 33,
"name": "Manchester United",
"logo": "https://media.api-sports.io/football/teams/33.png"
},
"points": 12,
"goalsDiff": 0,
"group": "Premier League",
"form": "WWWWL",
"status": "same",
"description": "Promotion - Europa League (Group Stage)",
"all": {
"played": 6,
"win": 4,
"draw": 0,
"lose": 2,
"goals": {
"for": 8,
"against": 8
}
},
"home": {
"played": 3,
"win": 2,
"draw": 0,
"lose": 1,
"goals": {
"for": 6,
"against": 4
}
},
"away": {
"played": 3,
"win": 2,
"draw": 0,
"lose": 1,
"goals": {
"for": 2,
"against": 4
}
},
"update": "2022-09-18T00:00:00+00:00"
},
{
"rank": 6,
"team": {
"id": 36,
"name": "Fulham",
"logo": "https://media.api-sports.io/football/teams/36.png"
},
"points": 11,
"goalsDiff": 1,
"group": "Premier League",
"form": "WLWLW",
"status": "same",
"description": null,
"all": {
"played": 7,
"win": 3,
"draw": 2,
"lose": 2,
"goals": {
"for": 12,
"against": 11
}
},
"home": {
"played": 3,
"win": 2,
"draw": 1,
"lose": 0,
"goals": {
"for": 7,
"against": 5
}
},
"away": {
"played": 4,
"win": 1,
"draw": 1,
"lose": 2,
"goals": {
"for": 5,
"against": 6
}
},
"update": "2022-09-18T00:00:00+00:00"
},
{
"rank": 7,
"team": {
"id": 49,
"name": "Chelsea",
"logo": "https://media.api-sports.io/football/teams/49.png"
},
"points": 10,
"goalsDiff": -1,
"group": "Premier League",
"form": "WLWLD",
"status": "same",
"description": null,
"all": {
"played": 6,
"win": 3,
"draw": 1,
"lose": 2,
"goals": {
"for": 8,
"against": 9
}
},
"home": {
"played": 3,
"win": 2,
"draw": 1,
"lose": 0,
"goals": {
"for": 6,
"against": 4
}
},
"away": {
"played": 3,
"win": 1,
"draw": 0,
"lose": 2,
"goals": {
"for": 2,
"against": 5
}
},
"update": "2022-09-18T00:00:00+00:00"
}
]
]
}
}

Answer 1

您可以将json的实例提供给https://app.quicktype.io/要获得基于的模型，下面是json模型的示例：

// To parse this JSON data, do
//
//     final standingLeague = standingLeagueFromMap(jsonString);
import 'package:meta/meta.dart';
import 'dart:convert';
StandingLeague standingLeagueFromMap(String str) => StandingLeague.fromMap(json.decode(str));
String standingLeagueToMap(StandingLeague data) => json.encode(data.toMap());
class StandingLeague {
StandingLeague({
@required this.league,
});
League league;
factory StandingLeague.fromMap(Map<String, dynamic> json) => StandingLeague(
league: League.fromMap(json["league"]),
);
Map<String, dynamic> toMap() => {
"league": league.toMap(),
};
}
class League {
League({
@required this.id,
@required this.name,
@required this.country,
@required this.logo,
@required this.flag,
@required this.season,
@required this.standings,
});
int id;
String name;
String country;
String logo;
String flag;
int season;
List<List<Standing>> standings;
factory League.fromMap(Map<String, dynamic> json) => League(
id: json["id"],
name: json["name"],
country: json["country"],
logo: json["logo"],
flag: json["flag"],
season: json["season"],
standings: List<List<Standing>>.from(json["standings"].map((x) => List<Standing>.from(x.map((x) => Standing.fromMap(x))))),
);
Map<String, dynamic> toMap() => {
"id": id,
"name": name,
"country": country,
"logo": logo,
"flag": flag,
"season": season,
"standings": List<dynamic>.from(standings.map((x) => List<dynamic>.from(x.map((x) => x.toMap())))),
};
}
class Standing {
Standing({
@required this.rank,
@required this.team,
@required this.points,
@required this.goalsDiff,
@required this.group,
@required this.form,
@required this.status,
@required this.description,
@required this.all,
@required this.home,
@required this.away,
@required this.update,
});
int rank;
Team team;
int points;
int goalsDiff;
String group;
String form;
String status;
String description;
All all;
All home;
All away;
DateTime update;
factory Standing.fromMap(Map<String, dynamic> json) => Standing(
rank: json["rank"],
team: Team.fromMap(json["team"]),
points: json["points"],
goalsDiff: json["goalsDiff"],
group: json["group"],
form: json["form"],
status: json["status"],
description: json["description"] == null ? null : json["description"],
all: All.fromMap(json["all"]),
home: All.fromMap(json["home"]),
away: All.fromMap(json["away"]),
update: DateTime.parse(json["update"]),
);
Map<String, dynamic> toMap() => {
"rank": rank,
"team": team.toMap(),
"points": points,
"goalsDiff": goalsDiff,
"group": group,
"form": form,
"status": status,
"description": description == null ? null : description,
"all": all.toMap(),
"home": home.toMap(),
"away": away.toMap(),
"update": update.toIso8601String(),
};
}
class All {
All({
@required this.played,
@required this.win,
@required this.draw,
@required this.lose,
@required this.goals,
});
int played;
int win;
int draw;
int lose;
Goals goals;
factory All.fromMap(Map<String, dynamic> json) => All(
played: json["played"],
win: json["win"],
draw: json["draw"],
lose: json["lose"],
goals: Goals.fromMap(json["goals"]),
);
Map<String, dynamic> toMap() => {
"played": played,
"win": win,
"draw": draw,
"lose": lose,
"goals": goals.toMap(),
};
}
class Goals {
Goals({
@required this.goalsFor,
@required this.against,
});
int goalsFor;
int against;
factory Goals.fromMap(Map<String, dynamic> json) => Goals(
goalsFor: json["for"],
against: json["against"],
);
Map<String, dynamic> toMap() => {
"for": goalsFor,
"against": against,
};
}
class Team {
Team({
@required this.id,
@required this.name,
@required this.logo,
});
int id;
String name;
String logo;
factory Team.fromMap(Map<String, dynamic> json) => Team(
id: json["id"],
name: json["name"],
logo: json["logo"],
);
Map<String, dynamic> toMap() => {
"id": id,
"name": name,
"logo": logo,
};
}

Answer 2

只需将所有json放入https://app.quicktype.io/它将给出一个模型，