Flutter 中的网络请求

import 'dart:convert';

Map userInfo = {
  "username":"LaVie",
  "age":28
};
print(userInfo);
//Map类型转为JSON字符串
String userInfoJson = jsonEncode(userInfo);
print(userInfoJson);
//JSON字符串转为Map类型
Map userInfoMap = jsonDecode(userInfoJson);
print(userInfoMap);

//GET请求
_getData() async {
  var apiUrl = "http://127.0.0.1:3000/news";

  var response = await http.get(apiUrl);
  if (response.statusCode == 200) {
    var jsonResponse = convert.jsonDecode(response.body);
    var itemCount = jsonResponse['totalItems'];
    print("Number of books about http: $itemCount.");
  } else {
    print("Request failed with status: ${response.statusCode}.");
  }
}

// POST请求
_postData() async {
  //服务器地址
  var apiUrl = "https://www.e-189.com/preciserequest/clientoper";
  //请求参数
  Map parameters = {"m": "registercount", "companyid": "28740"};
  //网络请求的返回数据
  var response = await http.post(apiUrl, body: parameters);
  //处理返回数据
  if (response.statusCode == 200) {
    print(response.body);
    var jsonResponse = convert.jsonDecode(response.body);
    var registercount = jsonResponse['registercount'];
    print("注册人数是$registercount人");
  } else {
    print("Request failed with status: ${response.statusCode}.");
  }
}

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

class SettingPage extends StatefulWidget {
  SettingPage({Key key}) : super(key: key);

  _SettingPageState createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  
  List _dataSources = [];

  //网络请求数据
  _requestData() async{
    //服务器地址
    var serverUrl = "http://a.itying.com/api/productlist";

    //处理网络请求下来的数据
    var response = await http.get(serverUrl);
    if (response.statusCode==200) {
      //Json解析为Map
      Map responseMap = convert.jsonDecode(response.body);
      print(responseMap);
      setState(() {
        this._dataSources = responseMap["result"];
      });
    } else {
      print("Request failed with status: ${response.statusCode}.");
    }

  }

  @override
  void initState() {
    super.initState();
    //页面一加载就执行网络请求
    this._requestData();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      /**
       * 这里通过一个三目来判断数据是否请求成功
       * 在数据请求成功之前，页面展示“加载中”
       * 数据请求成功之后，就加在ListView列表
       */
      child: this._dataSources.length==0?Text("加载中......"):ListView.builder(
        itemCount: this._dataSources.length,
        itemBuilder: (context, index){
          return ListTile(
            title: Text(this._dataSources[index]["title"]),
          );
        },
      ),
    );
  }
}

import 'dart:convert' as convert;
import 'package:flutter/material.dart';
import 'package:dio/dio.dart';

class SettingPage extends StatefulWidget {
  SettingPage({Key key}) : super(key: key);

  _SettingPageState createState() => _SettingPageState();
}

class _SettingPageState extends State<SettingPage> {
  
  List _dataSources = [];

  //网络请求数据
  _requestData() async {
    //服务器地址
    var serverUrl = "http://www.phonegap100.com/appapi.php?a=getPortalList&catid=20&page=1";

    //处理网络请求下来的数据
    var response = await Dio().get(serverUrl);
    if (response.statusCode == 200) {
      /**
       * 这里需要注意，response.data的数据类型是不一定的
       * 在实际做项目的时候需要判断一下类型，然后再做进一步处理
       */
      print(response.data);
      print(response.data is String);
      setState(() {
        this._dataSources = convert.jsonDecode(response.data)["result"];
        print("888,${this._dataSources}");
      });
    } else {
      print("Request failed with status: ${response.statusCode}.");
    }
  }

  @override
  void initState() {
    super.initState();
    //页面一加载就执行网络请求
    this._requestData();
  }

  @override
  Widget build(BuildContext context) {
    print("666,${this._dataSources}");
    return Container(
      /**
       * 这里通过一个三目来判断数据是否请求成功
       * 在数据请求成功之前，页面展示“加载中”
       * 数据请求成功之后，就加在ListView列表
       */
      child: this._dataSources.length == 0
          ? Text("加载中......")
          : ListView(
            children: this._dataSources.map((value){
              return ListTile(
                title: Text(value["title"]),
              );
            }).toList(),
          ),
    );
  }
}