flutter json字符串类型和Map类型的相互转换以及、ajax网络请求

拼搏现实的明天。 2021-07-24 17:30 1476阅读 0赞

1、类型转换
    	(1)引入
    		import 'dart:convert';
    		
    	(2)转换
    		json.encode(Map); 将Map类型转换成json字符串
    		json.decode(json); 将json字符串类型转换成Map
    
    2、网络请求
    	(1)dart库搜索http按文档配置
    	(2)引入
    		import 'dart:convert' as convert;
    		import 'package:http/http.dart' as http;
    	(3)网络请求,在异步函数中设置
    		
    		get:
    			var data= await http.get(url);
    		    if (response.statusCode == 200) {
    		        var res = convert.jsonDecode(data.body);
    			
    		 	 } else {
    		    	print('Request failed with status: ${data.statusCode}.');
    		    }
    		
    		post:
    			var data = await http.post(url, body: {'key': 'value','key2','value2'});
    			var res=convert.jsonDecode(response.body);

代码示例:

import 'dart:async';
    import 'dart:convert' as convert;
    import 'package:http/http.dart' as http;
    
    import 'package:flutter/material.dart';
    import 'package:date_format/date_format.dart';
    import 'package:flutter_cupertino_date_picker/flutter_cupertino_date_picker.dart';
    import 'package:flutter_swiper/flutter_swiper.dart';
    import 'package:fluttertoast/fluttertoast.dart';
    import 'package:myflutter/page/me.dart';
    
    
    class Home4 extends StatefulWidget { 
      Home4({ Key key}) : super(key: key);
    
      @override
      _Home2State createState() => _Home2State();
    }
    
    class _Home2State extends State<Home4> { 
      String news='哈哈';
      @override
      void initState() {  
        super.initState();
    
    
      }
      var url="http://api.tianapi.com/txapi/ncov/index?key=4a8edfc8ac5eae9b0c5bf08157abba96";
      get() async{ 
          var response = await http.get(url);
          if (response.statusCode == 200) { 
            var jsonResponse = convert.jsonDecode(response.body);
            setState(() { 
              this.news=jsonResponse["msg"];
            });
            print(jsonResponse);
      } else { 
        print('Request failed with status: ${response.statusCode}.');
        }
      }
      
      var url2="http://api.tianapi.com/txapi/ncov/index";
      post() async
      { 
        var response = await http.post(url, body: { 'key': '4a8edfc8ac5eae9b0c5bf08157abba96'});
        print(convert.jsonDecode(response.body));
      }
    
      @override
      Widget build(BuildContext context) { 
        return Container(
           child: Column(
            mainAxisAlignment: MainAxisAlignment.start,
             children: <Widget>[
               
              RaisedButton(
                child: Text(news),
                color: Theme.of(context).accentColor,
                onPressed: (){ 
                  get();
                },
              ),
              RaisedButton(
                child: Text('post'),
                color: Theme.of(context).accentColor,
                onPressed: (){ 
                  post();
                },
              ),
    
           ]),
        );
      }
    }
    
    
      
    
    
    // 因为表单组件需要改变状态,所以要使用有状态组件