5-2 HTTP Client 請求

1. 須導入convert及io包
2. 完整範例：

   import 'package:flutter/material.dart';
   import 'dart:convert';
   import 'dart:io';
   
   void main() => runApp(new MyApp());
   
   class MyApp extends StatelessWidget {
     void getWeatherData() async {
       try {
         HttpClient httpClient = new HttpClient();
         HttpClientRequest request = await httpClient.getUrl(Uri.parse("http://t.weather.sojson.com/api/weather/city/101030100"));
         HttpClientResponse response=await request.close();
         var result=await response.transform(utf8.decoder).join();
         print(result);
         httpClient.close();
       } catch (e) {
         print('請求失敗！');
       }
     }
   
     @override
     Widget build(BuildContext context) {
       return new MaterialApp(
         title: 'httpClient 請求範例',
         home: new Scaffold(
           appBar: new AppBar(
             title: new Text('httpClient 請求範例'),
           ),
           body: new Center(
             child: new RaisedButton(
               child: new Text('取得天氣數據'),
               onPressed: getWeatherData,
             ),
           ),
         ),
       );
     }
   }
   

   執行結果可以從編輯器下方的「偵錯主控台」觀看（並不會呈現在主機上）