Dio练习题2

示例有3个文件：

main.dart

import 'package:flutter/material.dart';
import 'httpgetdata.dart';
import 'modelpost.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('demoModel&Dio'),),
      body: FutureBuilder(
        future: GetData().getData(),
        builder: (context,snapshot){
          if(snapshot.hasData){
            var listData = snapshot.data.map((item)=>PostModel.fromJson(item)).toList();
            return ListView.builder(
              itemCount: snapshot.data.length,
              itemBuilder: (context,index){
                return ListTile(
                  title: Text('${listData[index].title}'),
                  subtitle: Text('${listData[index].body}'),
                );
              },
            );
          }else{
            return Center(child: CircularProgressIndicator(),);
          }
        },),
    );
  }
}


httpgetdata.dart

import 'package:http/http.dart' as http;
import 'package:dio/dio.dart';
import 'dart:convert';

class GetData{
  String url = 'http://jsonplaceholder.typicode.com/posts';
  var backData;
  getData()async{
    Response response = await Dio().get(url);
    if(response.statusCode==200){
      return response.data;
    }else{
      return ['there is no data get from website'];
    }
  }
}

modelpost.dart

class PostModel{
  //下面两个数据要根据实际的Json数据填写；
  final int userId;
  final int id;
  final String title;
  final String body;

  PostModel(
      this.userId,
      this.id,
      this.title,
      this.body,
      );
  //PostModel.fromJson(Map json)输入的参数是一个Map类型Map json；输出的是PostModel类型数据；
  PostModel.fromJson(Map json)
      :userId=json['userId'],
        id=json['id'],
        title = json['title'],
        body = json['body'];
  // Map toJson()返回的是Map类型数据，是将Post类数据序列化为Json;
  Map toJson() => {
    'id':id,
    'userId':userId,
    'title':title,
    'body':body,
  };
}