如何设置工厂专辑以映射自定义REST API JSON BODON

Question

，但是我迷失了自定义专辑以匹配REST API JSON数据。特别是，正确设置专辑以容纳一系列对象（项目）和元对象。代码示例优先。预先感谢！

示例JSON数据来自RESTAPI

{
  "projects": [
   {
    "id": "7c635c45-ebab-44fc-8141-2157e062f97d",
    "name": "Project 1",
    "description": "Project description",
    "notice_to_proceed_date": "2024-01-01",
    "business_id": 4046,
    "status": "construction",
    "awarded_amount": "799109.2",
    "authorized_amount": "799109.2",
    "business_name": "My Business Name"
  },
  {
    "id": "8528ebbb-54db-40e2-ba0d-1a90e3dfdfb7",
    "name": "Project 2",
    "description": "Project description",
    "notice_to_proceed_date": "2024-03-03",
    "business_id": 4046,
    "status": "construction",
    "awarded_amount": "31166.03",
    "authorized_amount": "31166.03",
    "business_name": "My Business Name"
  }
 ],
 "meta": {
   "current_page": 1,
   "next_page": null,
   "prev_page": null,
   "total_pages": 1,
   "total_count": 2
 }
}

我的代码

import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;


Future<Album> fetchAlbum() async {
  final response = await http.get(
    Uri.parse('https://api.demo.platform.infotechinc.com/appia/v3/projects'),
    // Send authorization headers to the backend
    headers: {
      HttpHeaders.authorizationHeader: 'Bearer     7bec66...'
    },
  );

  if (response.statusCode == 200) {
    // If the server did return a 200 OK response,
    // then parse the JSON.
    return Album.fromJson(jsonDecode(response.body) as Map<String, dynamic>);
  } else {
    // If the server did not return a 200 OK response,
    // then throw an exception.
    throw Exception('Failed to load album');
  }
}

class Album {
  final String id;
  final String name;
  final String description;
  final String notice_to_proceed_date;
  final int business_id;
  final String status;
  final String awarded_amount;
  final String authorized_amount;
  final String business_name;

  const Album({
    required this.id,
    required this.name,
    required this.description,
    required this.notice_to_proceed_date,
    required this.business_id,
    required this.status,
    required this.awarded_amount,
    required this.authorized_amount,
    required this.business_name,
  });

  factory Album.fromJson(Map<String, dynamic> json) {
    return switch (json) {
      {
      'id': String id,
      'name': String name,
      'description': String description,
      'notice_to_proceed_date': String notice_to_proceed_date,
      'business_id': int business_id,
      'status': String status,
      'awarded_amount': String awarded_amount,
      'authorized_amount': String authorized_amount,
      'business_name': String business_name,
      } =>
          Album(
            id: id,
            name: name,
            description: description,
            notice_to_proceed_date: notice_to_proceed_date,
            business_id: business_id,
            status: status,
            awarded_amount: awarded_amount,
            authorized_amount: authorized_amount,
            business_name: business_name,
          ),
      _=> throw const FormatException('Failed to load album.'),
    };
  }
}

void main() => runApp(const MyApp());

 class MyApp extends StatefulWidget {
   const MyApp({super.key});

   @override
   State<MyApp> createState() => _MyAppState();
 }

class _MyAppState extends State<MyApp> {
  late Future<Album> futureAlbum;

  @override
  void initState() {
    super.initState();
    futureAlbum = fetchAlbum();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Fetch Data Example',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Fetch Data Example'),
        ),
        body: Center(
          child: FutureBuilder<Album>(
            future: futureAlbum,
            builder: (context, snapshot) {
              if (snapshot.hasData) {
                return Text(snapshot.data!.name);
              } else if (snapshot.hasError) {
                return Text('${snapshot.error}');
              }

              // By default, show a loading spinner.
              return const CircularProgressIndicator();
            },
          ),
        ),
      ),
    );
  }
}

link link to api文档

https：//infotechinc.stoplight.io/docs/appia/df3aded65f065-list-all-projects

这里是更新的代码。

预期响应

{
  "projects": [
   {
    "id": "7c635c45-ebab-44fc-8141-2157e062f97d",
    "name": "Project 1",
    "description": "Project description",
    "notice_to_proceed_date": "2024-01-01",
    "business_id": 4046,
    "status": "construction",
    "awarded_amount": "799109.2",
    "authorized_amount": "799109.2",
    "business_name": "My Business Name"
  },
  {
    "id": "8528ebbb-54db-40e2-ba0d-1a90e3dfdfb7",
    "name": "Project 2",
    "description": "Project description",
    "notice_to_proceed_date": "2024-03-03",
    "business_id": 4046,
    "status": "construction",
    "awarded_amount": "31166.03",
    "authorized_amount": "31166.03",
    "business_name": "My Business Name"
  }
 ],
 "meta": {
   "current_page": 1,
   "next_page": null,
   "prev_page": null,
   "total_pages": 1,
   "total_count": 2
 }
}

Answer 1

模型 它被重命名以匹配预期数据

class Project {
  final String? id;
  final String? name;
  final String? description;
  final DateTime? noticeToProceedDate;
  final int? businessId;
  final String? status;
  final String? awardedAmount;
  final String? authorizedAmount;
  final String? businessName;

  Project({
    this.id,
    this.name,
    this.description,
    this.noticeToProceedDate,
    this.businessId,
    this.status,
    this.awardedAmount,
    this.authorizedAmount,
    this.businessName,
  });

  Project copyWith({
    String? id,
    String? name,
    String? description,
    DateTime? noticeToProceedDate,
    int? businessId,
    String? status,
    String? awardedAmount,
    String? authorizedAmount,
    String? businessName,
  }) =>
      Project(
        id: id ?? this.id,
        name: name ?? this.name,
        description: description ?? this.description,
        noticeToProceedDate: noticeToProceedDate ?? this.noticeToProceedDate,
        businessId: businessId ?? this.businessId,
        status: status ?? this.status,
        awardedAmount: awardedAmount ?? this.awardedAmount,
        authorizedAmount: authorizedAmount ?? this.authorizedAmount,
        businessName: businessName ?? this.businessName,
      );

  factory Project.fromJson(Map<String, dynamic> json) => Project(
        id: json["id"],
        name: json["name"],
        description: json["description"],
        noticeToProceedDate: json["notice_to_proceed_date"] == null
            ? null
            : DateTime.parse(json["notice_to_proceed_date"]),
        businessId: json["business_id"],
        status: json["status"],
        awardedAmount: json["awarded_amount"],
        authorizedAmount: json["authorized_amount"],
        businessName: json["business_name"],
      );

  Map<String, dynamic> toJson() => {
        "id": id,
        "name": name,
        "description": description,
        "notice_to_proceed_date":
            "${noticeToProceedDate!.year.toString().padLeft(4, '0')}-${noticeToProceedDate!.month.toString().padLeft(2, '0')}-${noticeToProceedDate!.day.toString().padLeft(2, '0')}",
        "business_id": businessId,
        "status": status,
        "awarded_amount": awardedAmount,
        "authorized_amount": authorizedAmount,
        "business_name": businessName,
      };
}

api呼叫

API呼叫的重命名还指出，项目密钥是一个列表，我们获取每个项目并将其映射到我们的项目模型

Future<List<Project>?> fetchProjects() async {
  final response = await http.get(
    Uri.parse('https://api.demo.platform.infotechinc.com/appia/v3/projects'),
    // Send authorization headers to the backend
    headers: {HttpHeaders.authorizationHeader: 'Bearer     7bec66...'},
  );

  if (response.statusCode == 200) {
    // If the server did return a 200 OK response,
    // then parse the JSON.
    return List<Project>.from(
        ((jsonDecode(response.body)?['projects'] as List?) ?? [])
            .map((e) => Project.fromJson(e)));
  } else {
    // If the server did not return a 200 OK response,
    // then throw an exception.
    throw Exception('Failed to load album');
  }
}

main.dart

void main() => runApp(const MyApp());

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  late Future<List<Project>?> futureAlbum;

  @override
  void initState() {
    super.initState();
    futureAlbum = fetchProjects();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Fetch Data Example',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Fetch Data Example'),
        ),
        body: Center(
          child: FutureBuilder<List<Project>?>(
            future: futureAlbum,
            builder: (context, snapshot) {
              if (snapshot.hasData) {
                return Expanded(
                  child: ListView.builder(
                    itemBuilder: (_, i) {
                      final name = snapshot.data?[i].name;

                      return Text(name ?? "");
                    },
                    itemCount: snapshot.data?.length,
                    shrinkWrap: true,
                  ),
                );
              } else if (snapshot.hasError) {
                return Text('${snapshot.error}');
              }

              // By default, show a loading spinner.
              return const CircularProgressIndicator();
            },
          ),
        ),
      ),
    );
  }
}