从嵌套的 JSON Flutter 中获取值和键

Question

所以，这是一个经过编辑的问题。在我按照建议使用 json 到转换器之后，我设法生成了这个

// To parse this JSON data, do
//
//     final user = userFromJson(jsonString);

import 'dart:convert';

Map<String, Map<String, Map<String, Map<String, User>>>> userFromJson(String str) => new Map.from(json.decode(str)).map((k, v) => new MapEntry<String, Map<String, Map<String, Map<String, User>>>>(k, new Map.from(v).map((k, v) => new MapEntry<String, Map<String, Map<String, User>>>(k, new Map.from(v).map((k, v) => new MapEntry<String, Map<String, User>>(k, new Map.from(v).map((k, v) => new MapEntry<String, User>(k, User.fromJson(v)))))))));

String userToJson(Map<String, Map<String, Map<String, Map<String, User>>>> data) => json.encode(new Map.from(data).map((k, v) => new MapEntry<String, dynamic>(k, new Map.from(v).map((k, v) => new MapEntry<String, dynamic>(k, new Map.from(v).map((k, v) => new MapEntry<String, dynamic>(k, new Map.from(v).map((k, v) => new MapEntry<String, dynamic>(k, v.toJson())))))))));

class User {
    String userClass;
    String name;

    User({
        this.userClass,
        this.name,
    });

    factory User.fromJson(Map<String, dynamic> json) => new User(
        userClass: json["class"],
        name: json["name"],
    );

    Map<String, dynamic> toJson() => {
        "class": userClass,
        "name": name,
    };
}

但是，当我尝试访问 userClass 和 name 时，它​​返回 null

这是我的json。 如果我这样做

final val = json.decode(jsonString);
final data = User.fromJson(val); 

数据将返回“用户实例”。 如果我使用

final user = userFromJson(jsonString);

我会得到这个： {12341：{2014：{11：{21：“用户”实例}}}，46546：{2013：{11：{21：“用户”实例}}}}

Answer 1

将您的 JSON 字符串粘贴到 https://app.quicktype.io/，它将验证您的 JSON 字符串并转换为您需要的类。

示例学生 JSON 字符串

[
  {
    "ID": "1",
    "Name": "Senpai",
    "Gender": "1",
    "Class": "32",
    "Seat": "15",
    "Club": "0",
    "Persona": "1",
    "Crush": "0",
    "BreastSize": "0",
    "Strength": "0",
    "Hairstyle": "1",
    "Color": "Black",
    "Eyes": "Black",
    "EyeType": "Default",
    "Stockings": "None",
    "Accessory": "0",
    "ScheduleTime": "7_7_8_13.01_13.375_15.5_16_17.25_99_99",
    "ScheduleDestination": "Spawn_Locker_Hangout_Seat_LunchSpot_Seat_Clean_Hangout_Locker_Exit",
    "ScheduleAction": "Stand_Stand_Read_Sit_Eat_Sit_Clean_Read_Shoes_Stand",
    "Info": "An average student. \n \n Average grades, average looks, average life... \n \n I'm not sure what you see in him."
  },
  {
    "ID": "2",
    "Name": "Yui Rio",
    "Gender": "0",
    "Class": "11",
    "Seat": "14",
    "Club": "1",
    "Persona": "5",
    "Crush": "0",
    "BreastSize": "0.5",
    "Strength": "0",
    "Hairstyle": "2",
    "Color": "Red",
    "Eyes": "Red",
    "EyeType": "Default",
    "Stockings": "Red",
    "Accessory": "0",
    "ScheduleTime": "7_7_8_13_13.375_15.5_16_17.25_99_99",
    "ScheduleDestination": "Spawn_Locker_Hangout_Seat_LunchSpot_Seat_Clean_Club_Locker_Exit",
    "ScheduleAction": "Stand_Stand_Socialize_Sit_Socialize_Sit_Clean_SocialSit_Shoes_Stand",
    "Info": ""
  }
]

和解析这个例子的代码

// To parse this JSON data, do
//
//     final payload = payloadFromJson(jsonString);

import 'dart:convert';

List<Payload> payloadFromJson(String str) => new List<Payload>.from(json.decode(str).map((x) => Payload.fromJson(x)));

String payloadToJson(List<Payload> data) => json.encode(new List<dynamic>.from(data.map((x) => x.toJson())));

class Payload {
    String id;
    String name;
    String gender;
    String payloadClass;
    String seat;
    String club;
    String persona;
    String crush;
    String breastSize;
    String strength;
    String hairstyle;
    String color;
    String eyes;
    String eyeType;
    String stockings;
    String accessory;
    String scheduleTime;
    String scheduleDestination;
    String scheduleAction;
    String info;

    Payload({
        this.id,
        this.name,
        this.gender,
        this.payloadClass,
        this.seat,
        this.club,
        this.persona,
        this.crush,
        this.breastSize,
        this.strength,
        this.hairstyle,
        this.color,
        this.eyes,
        this.eyeType,
        this.stockings,
        this.accessory,
        this.scheduleTime,
        this.scheduleDestination,
        this.scheduleAction,
        this.info,
    });

    factory Payload.fromJson(Map<String, dynamic> json) => new Payload(
        id: json["ID"],
        name: json["Name"],
        gender: json["Gender"],
        payloadClass: json["Class"],
        seat: json["Seat"],
        club: json["Club"],
        persona: json["Persona"],
        crush: json["Crush"],
        breastSize: json["BreastSize"],
        strength: json["Strength"],
        hairstyle: json["Hairstyle"],
        color: json["Color"],
        eyes: json["Eyes"],
        eyeType: json["EyeType"],
        stockings: json["Stockings"],
        accessory: json["Accessory"],
        scheduleTime: json["ScheduleTime"],
        scheduleDestination: json["ScheduleDestination"],
        scheduleAction: json["ScheduleAction"],
        info: json["Info"],
    );

    Map<String, dynamic> toJson() => {
        "ID": id,
        "Name": name,
        "Gender": gender,
        "Class": payloadClass,
        "Seat": seat,
        "Club": club,
        "Persona": persona,
        "Crush": crush,
        "BreastSize": breastSize,
        "Strength": strength,
        "Hairstyle": hairstyle,
        "Color": color,
        "Eyes": eyes,
        "EyeType": eyeType,
        "Stockings": stockings,
        "Accessory": accessory,
        "ScheduleTime": scheduleTime,
        "ScheduleDestination": scheduleDestination,
        "ScheduleAction": scheduleAction,
        "Info": info,
    };
}

关于您的 JSON 字符串，您可以使用以下内容对其进行解析

// To parse this JSON data, do
//
//     final payload = payloadFromJson(jsonString);

import 'dart:convert';

Payload payloadFromJson(String str) => Payload.fromJson(json.decode(str));

String payloadToJson(Payload data) => json.encode(data.toJson());

class Payload {
    The12341 the12341;

    Payload({
        this.the12341,
    });

    factory Payload.fromJson(Map<String, dynamic> json) => new Payload(
        the12341: The12341.fromJson(json["12341"]),
    );

    Map<String, dynamic> toJson() => {
        "12341": the12341.toJson(),
    };
}

class The12341 {
    The2014 the2014;

    The12341({
        this.the2014,
    });

    factory The12341.fromJson(Map<String, dynamic> json) => new The12341(
        the2014: The2014.fromJson(json["2014"]),
    );

    Map<String, dynamic> toJson() => {
        "2014": the2014.toJson(),
    };
}

class The2014 {
    The11 the11;

    The2014({
        this.the11,
    });

    factory The2014.fromJson(Map<String, dynamic> json) => new The2014(
        the11: The11.fromJson(json["11"]),
    );

    Map<String, dynamic> toJson() => {
        "11": the11.toJson(),
    };
}

class The11 {
    The21 the21;

    The11({
        this.the21,
    });

    factory The11.fromJson(Map<String, dynamic> json) => new The11(
        the21: The21.fromJson(json["21"]),
    );

    Map<String, dynamic> toJson() => {
        "21": the21.toJson(),
    };
}

class The21 {
    String the21Class;
    String name;

    The21({
        this.the21Class,
        this.name,
    });

    factory The21.fromJson(Map<String, dynamic> json) => new The21(
        the21Class: json["class"],
        name: json["name"],
    );

    Map<String, dynamic> toJson() => {
        "class": the21Class,
        "name": name,
    };
}