Flutter笔记-Http网络请求

参考资料：https://blog.csdn.net/duo_shine/article/details/81280614

flutter http网络请求,可以使用已有的插件来完成。
插件版本： http: ^0.11.3+16
插件引入：
pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  http: ^0.11.3+16

http工具类：

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

class HttpManager {
  //  三天预报
  var forecast_url = "https://free-api.heweather.com/s6/weather/forecast?parameters";
  //实况天气
  var new_weather_url = "https://free-api.heweather.com/s6/weather/now?parameters";

  /**
   * 三天预报
   * cityName 城市名称 我们应该使用外部传入
   * net 监听网络请求的结果 因为他不是同步的
   */
  getForecast(NetListener net, String cityName) {
      var client = new http.Client();
      client.post(
        forecast_url,
        body: {
          'location': cityName,
          'key': 'eaf572c8304f4eeb8ad209bf05da2872'
        }
      ).then((response){
        net.onForecastResponse(response.body);
      },onError: (error){
        net.onError(error);
      }).whenComplete(
        client.close
      );
  }


  /**
   * 获取实况天气
   */
  getNewWeather(NetListener net,String cityName)  {
    var client = new http.Client();
    client.post(
      new_weather_url,
      body: {
        "location": cityName,
        "key": "eaf572c8304f4eeb8ad209bf05da2872",
      },
    ).then((
        response,
        ) {
      net.onNewWeatherResponse(response.body);
    }, onError: (error) {
      net.onError(error);
    }).whenComplete(
      client.close,
    );
  }

}


/**
 * 用来回调成功和失败的结果
 */
abstract class NetListener {
  //实况天气
  void onNewWeatherResponse(String body);
  //三天预报
  void onForecastResponse(String body);

  void onError(error);
}

调用方式

import 'dart:async';
import 'package:flutter/material.dart';
import 'HttpUtil.dart';

void main(){
  runApp(new MaterialApp(
    title: 'input',
    home: new Scaffold(
      appBar: new AppBar(title: new Text('输入事件'),),
      body: new MyWeather(),
    ),
  ));
}

class MyWeather extends StatefulWidget {
  @override
  State createState() {
    // TODO: implement createState
    return new MyWeatherState();
  }
}

class MyWeatherState extends State with NetListener{
  var weather = 'delay';
  HttpManager httpManager = new HttpManager();

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return new Container(
      child: new Column(
        children: [
          new RaisedButton(
              child: new Text('三天的预报'),
              onPressed: (){
                _getWeatherForecast();
              }),
          new RaisedButton(
              child: new Text('获取实时天气'),
              onPressed: (){
                _getWeatherNewWeather();
              }),
          new Expanded(
              child: new Center(
                child: new ListView(
                  children: [
                    new Text('$weather')
                  ],
                ),
              )
          )
        ],
      ),
    );
  }

  /**
   * 获取三天的预报
   */
  _getWeatherForecast() async {
    print('请求获取三天的预报');
    await httpManager.getForecast(this, '朝阳区');
  }

  /**
   * 获取实况天气
   */
  _getWeatherNewWeather() async {
    await httpManager.getNewWeather(this, "浦东新区");
  }

  /**
   * 获取实况天气
   */
  @override
  void onNewWeatherResponse(String body) {
    weather = body;
    setState(() {});
  }

  @override
  void onError(error) {
    // TODO: implement onError
  }

  @override
  void onForecastResponse(String body) {
    print('响应获取三天的预报');
    weather = body;
    setState(() {});
  }

}

结果图：