import React, { Component } from 'react';

 import {

     AppRegistry,

     StyleSheet,

     Text,

     View

 } from 'react-native';

 //默认应用的容器组件

 export default class App extends Component {

     //构造函数

     constructor(props) {

         super(props);

         this.state = {

             responseText: null

         };

     }

     //渲染

     render() {

         return (

             <View style={styles.container}>

                 <Text style={styles.item} onPress={this.doXMLHttpRequest.bind(this)}>获取数据</Text>

                 <Text>{this.state.responseText}</Text>

             </View>

         );

     }

     //使用XMLHttpRequest请求数据

     doXMLHttpRequest(){

         var request = new XMLHttpRequest();

         request.onreadystatechange = (e) => {

             if (request.readyState !== 4) {

                 return;

             }

             if (request.status === 200) {

                 alert("请求成功！");

                 this.setState({responseText: request.responseText})

                 console.log(request.responseText);

             } else {

                 alert("请求失败！");

             }

         };

         request.open('GET', 'https://httpbin.org/get');

         request.send();

     }

 }

 //样式定义

 const styles = StyleSheet.create({

     container:{

         flex: 1,

         marginTop:25

     },

     item:{

         margin:15,

         height:30,

         borderWidth:1,

         padding:6,

         borderColor:'#ddd',

         textAlign:'center'

     },

 });