Flutter和Dart系列九：簡單的網絡請求

與其說是Flutter的網絡請求，倒不如說是Dart的網絡請求。實際上這塊是對系列八第5點的一個複習，我們直接看代碼：

1. 在.yaml文件中添加http依賴，然後執行Packages get

   dependencies:
     flutter:
       sdk: flutter
     http: ^0.12.0+2
   

2. 新建一個api.dart文件

   import 'package:http/http.dart' as http;
   
   class ServerApi {
     static Future<String> getArticle() async {
       var url = "https://interface.meiriyiwen.com/article/today?dev=1";
       return _doGet(url);
     }
   
     static Future<String> _doGet(String url) async {
       http.Response response = await http.get(url);
       return response.body;
     }
   }
   

   • 就是對Future、async以及await關鍵字的使用，這塊系列八已經介紹過
   • 應用了我們剛剛添加依賴的http庫

3. 在main.dart文件中添加如下代碼，我們就直接使用一個剛新建的Flutter工程：

   void _incrementCounter() {
       setState(() {
         // This call to setState tells the Flutter framework that something has
         // changed in this State, which causes it to rerun the build method below
         // so that the display can reflect the updated values. If we changed
         // _counter without calling setState(), then the build method would not be
         // called again, and so nothing would appear to happen.
   //      _counter++;
         ServerApi.getArticle().then((json) {
           print("json: $json");
         });
       });
     }
   

   改變一下FAB的點擊響應，在這裏發起網絡請求，這裏直接打印返回的json，如果在實際項目中可以對json進行解析成實體類對象然後使用。打印結果如下：