FlutterのAndroid）と同様に、JSONをPOJO（オブジェクト）に変換します
Json応答（REST APIから）をPOJO（Androidで使用）に変換して、受信したデータをアプリケーションで使用できるようにする方法を見つけようとしています。私が受け取っているデータは少し複雑で、3つのレベルの配列（配列内の配列内の配列）が含まれているため、マップは十分ではありません。
API呼び出しにDioライブラリを使用していますが、API呼び出しを正常に実行し、問題なくコンソールにデータを出力できます。誰かがこれを達成するのを手伝ってくれる？
以下は私が得ている応答です。
{
"status": 200,
"message": "success",
"data": [
{
"menu": {
"megamenu_id": "55",
"language_id": "1",
"title": "Mobiles",
"description": "",
"submenu": [
{
"0": {
"info": {
"megamenu_id": "67",
"language_id": "1",
"title": "Mobile Phones",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "68",
"language_id": "1",
"title": "Android Phones",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "69",
"language_id": "1",
"title": "Smart Phones",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "70",
"language_id": "1",
"title": "Windows Phones",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "72",
"language_id": "1",
"title": "Basic Phones",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "73",
"language_id": "1",
"title": "Latest Mobiles",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "74",
"language_id": "1",
"title": "Upcoming Mobiles",
"description": ""
}
}
]
},
{
"0": {
"info": {
"megamenu_id": "75",
"language_id": "1",
"title": "Brands",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "76",
"language_id": "1",
"title": "Samsung",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "77",
"language_id": "1",
"title": "Apple",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "78",
"language_id": "1",
"title": "Redmi",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "79",
"language_id": "1",
"title": "Nokia",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "81",
"language_id": "1",
"title": "Sony",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "82",
"language_id": "1",
"title": "Micromax",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "83",
"language_id": "1",
"title": "HTC",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "84",
"language_id": "1",
"title": "Motorola",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "85",
"language_id": "1",
"title": "Oppo",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "86",
"language_id": "1",
"title": "Vivo",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "87",
"language_id": "1",
"title": "Honor",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "88",
"language_id": "1",
"title": "Oneplus",
"description": ""
}
}
]
},
{
"0": {
"info": {
"megamenu_id": "94",
"language_id": "1",
"title": "Mobile Accessories",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "95",
"language_id": "1",
"title": "Bluetooth Headsets",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "96",
"language_id": "1",
"title": "Mobile Chargers",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "97",
"language_id": "1",
"title": "Mobiles Cases & Covers",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "98",
"language_id": "1",
"title": "Screen Protector",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "99",
"language_id": "1",
"title": "Mobile Batteries",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "100",
"language_id": "1",
"title": "Headphones & Headsets",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "101",
"language_id": "1",
"title": "Memory Cards",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "102",
"language_id": "1",
"title": "Power Banks",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "103",
"language_id": "1",
"title": "Stylus",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "104",
"language_id": "1",
"title": "Mobile Docks",
"description": ""
}
}
]
},
{
"0": {
"info": {
"megamenu_id": "107",
"language_id": "1",
"title": "Features",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "108",
"language_id": "1",
"title": "Dual Sim Phones",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "111",
"language_id": "1",
"title": "4GB Ram Mobiles",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "112",
"language_id": "1",
"title": "Rear Camera [13 MP]",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "113",
"language_id": "1",
"title": "Screen Size [4.5 - 5.2 Inch]",
"description": ""
}
}
]
}
]
}
},
{
"menu": {
"megamenu_id": "168",
"language_id": "1",
"title": "Fashion",
"description": "",
"submenu": [
{
"0": {
"info": {
"megamenu_id": "169",
"language_id": "1",
"title": "Clothing",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "170",
"language_id": "1",
"title": "T-Shirts",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "171",
"language_id": "1",
"title": "Shirts",
"description": ""
}
}
]
},
{
"0": {
"info": {
"megamenu_id": "178",
"language_id": "1",
"title": "Womens Clothing",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "187",
"language_id": "1",
"title": "Night Wear",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "188",
"language_id": "1",
"title": "Tunics",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "189",
"language_id": "1",
"title": "Kurtis",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "190",
"language_id": "1",
"title": "Sarees",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "191",
"language_id": "1",
"title": "Lehengas",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "192",
"language_id": "1",
"title": "Swimming Suit",
"description": ""
}
}
]
},
{
"0": {
"info": {
"megamenu_id": "193",
"language_id": "1",
"title": "Men's Footwear",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "194",
"language_id": "1",
"title": "Shoes",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "195",
"language_id": "1",
"title": "Sneakers",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "196",
"language_id": "1",
"title": "Sandals & Floaters",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "197",
"language_id": "1",
"title": "Slippers & Flip Flops",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "198",
"language_id": "1",
"title": "Loafers",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "199",
"language_id": "1",
"title": "Boots",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "200",
"language_id": "1",
"title": "Shoe Care",
"description": ""
}
}
]
},
{
"0": {
"info": {
"megamenu_id": "201",
"language_id": "1",
"title": "Women's Jewellery",
"description": ""
}
},
"subsubmenu": [
{
"infosub": {
"megamenu_id": "202",
"language_id": "1",
"title": "Earrings",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "203",
"language_id": "1",
"title": "Bangles",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "204",
"language_id": "1",
"title": "Bracelets",
"description": ""
}
},
{
"infosub": {
"megamenu_id": "205",
"language_id": "1",
"title": "Rings",
"description": ""
}
}
]
}
]
}
},
{
"menu": {
"megamenu_id": "220",
"language_id": "1",
"title": "Care",
"description": ""
}
},
{
"menu": {
"megamenu_id": "221",
"language_id": "1",
"title": "Offers",
"description": ""
}
},
{
"menu": {
"megamenu_id": "222",
"language_id": "1",
"title": "News",
"description": ""
}
}
]
}
そのため、json_serializableライブラリを試してみた後、独自のソリューションを思いつきました。外部ライブラリはまったく必要なく、魅力のように機能します。このようにして、ボイラープレートコードを少なくする必要があり、これを行うためのクリーンな方法だと思います。
モデルの作り方は次のとおりです
class SideMenuRes {
final int status;
final String message;
final List<SideMenuDatum> sideMenuData;
SideMenuRes({this.status, this.message, this.sideMenuData});
factory SideMenuRes.fromJson(Map json) {
return SideMenuRes(
status: json['status'],
message: json['message'],
sideMenuData: json['status'] == 200 ? (json['data'] as List).map((i) => new
SideMenuDatum.fromJson(i)).toList() : null,
);
}
}
class SideMenuDatum {
final Menu menu;
SideMenuDatum({this.menu});
factory SideMenuDatum.fromJson(Map json) {
return SideMenuDatum(
menu: Menu.fromJson(json['menu']),
);
}
}
class Menu {
final String megamenu_id;
final String language_id;
final String title;
final String description;
final List<SubMenu> subMenu;
Menu({this.megamenu_id, this.language_id, this.title, this.description, this.subMenu});
factory Menu.fromJson(Map json) {
return Menu(
megamenu_id: json['megamenu_id'],
language_id: json['language_id'],
title: json['title'],
description: json['description'],
subMenu: json['submenu'] != null ? (json['submenu'] as List).map((i) => new SubMenu.fromJson(i)).toList() : null
);
}
}
class SubMenu {
final Zero zero;
final List<SubSubMenu> subSubMenu;
SubMenu({this.zero, this.subSubMenu});
factory SubMenu.fromJson(Map json) {
return SubMenu(
zero: Zero.fromJson(json['0']),
subSubMenu: (json['subsubmenu'] as List).map((i) => new SubSubMenu.fromJson(i)).toList()
);
}
}
class Zero {
final Info info;
Zero({this.info});
factory Zero.fromJson(Map json) {
return Zero(
info: Info.fromJson(json['info']),
);
}
}
class SubSubMenu {
final InfoSub infoSub;
SubSubMenu({this.infoSub});
factory SubSubMenu.fromJson(Map json) {
return SubSubMenu(
infoSub: InfoSub.fromJson(json['infosub'])
);
}
}
class InfoSub {
final String megamenu_id;
final String language_id;
final String title;
final String description;
InfoSub({this.megamenu_id, this.language_id, this.title, this.description});
factory InfoSub.fromJson(Map json) {
return InfoSub(
megamenu_id: json['megamenu_id'],
language_id: json['language_id'],
title: json['title'],
description: json['description']
);
}
}
class Info {
final String megamenu_id;
final String language_id;
final String title;
final String description;
Info({this.megamenu_id, this.language_id, this.title, this.description});
factory Info.fromJson(Map json) {
return Info(
megamenu_id: json['megamenu_id'],
language_id: json['language_id'],
title: json['title'],
description: json['description']
);
}
}
そしてそれをこのように呼ぶ
SubMenuRes subMenuRes = SubMenuRes.fromJson(response.data);
それでおしまい！
Android Studioプラグイン： https://plugins.jetbrains.com/plugin/11460-json2Dart/
オンライン： https://javiercbk.github.io/json_to_Dart/
手動で解析： https://medium.com/flutter-community/parsing-complex-json-in-flutter-747c46655f51
JsonからDartクラスを生成する
JSONをDartクラスに変換する
JSONまたはJSON-SchemaからDartクラスを生成します。
json_serializable は十分に文書化されていませんが、特に配列に関しては、built_valueよりも使いやすく、必要な定型文が少なくて済みます。
import 'package:json_annotation/json_annotation.Dart';
import 'Dart:convert';
part 'school.g.Dart';
@JsonSerializable()
class School {
final String name;
final int maxStudentCount;
final List<Student> students;
School(this.name, this.maxStudentCount, this.students);
factory School.fromJson(Map<String, dynamic> json) => _$SchoolFromJson(json);
Map<String, dynamic> toJson() => _$SchoolToJson(this);
}
@JsonSerializable()
class Student {
final String name;
final DateTime birthDate;
Student({this.name, this.birthDate});
factory Student.fromJson(Map<String, dynamic> json) => _$StudentFromJson(json);
Map<String, dynamic> toJson() => _$StudentToJson(this);
}
test() {
String jsonString = '''{
"name":"Trump University",
"maxStudentCount":9999,
"students":[
{
"name":"Peter Parker",
"birthDate":"1999-01-01T00:00:00.000Z"
}
]
}''';
final decodedJson = json.decode(jsonString);
final school = School.fromJson(decodedJson);
assert(school.students.length == 1);
}
また、列挙型のシリアル化もサポートしています。
シリアル化コードを生成するには、次のコマンドを実行します。
flutter packages pub run build_runner build
これは、built_valueを使用して実行できます。詳細なドキュメントは、この リンク にあります。
ボイラープレートコードを記述して、このコマンドを実行するだけですflutter packages pub run build_runner build。
以下は、POJOのようなサンプルクラスです。
import 'package:built_value/built_value.Dart';
import 'package:built_value/serializer.Dart';
part 'auth.g.Dart';
abstract class Auth implements Built<Auth, AuthBuilder> {
static Serializer<Auth> get serializer => _$authSerializer;
String get currentServerTime;
int get defaultOrganization;
String get tokenExpiryTimeInMs;
bool get rememberMe;
int get failedLoginAttempts;
int get userId;
String get status;
String get token;
Auth._();
factory Auth([updates(AuthBuilder b)]) = _$Auth;
}
以下はSerializerクラスです。
library serializers;
import 'package:built_value/serializer.Dart';
import 'package:built_value/standard_json_plugin.Dart';
import 'auth/auth.Dart';
part 'serializers.g.Dart';
@SerializersFor(const [
Auth,
])
Serializers serializers = _$serializers;
Serializers standardSerializers =
(serializers.toBuilder()..addPlugin(StandardJsonPlugin())).build();
以下は、JSONからオブジェクトへの変換が行われるコードです。
Auth auth = standardSerializers.deserializeWith(
Auth.serializer, json.decode(res.body)['user']);
お役に立てれば。
この投稿 を見て、目標に最適なオプションを取得してください