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.doFetch.bind(this)}>获取数据</Text>

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

             </View>

         );

     }

     //使用Fetch请求数据

     doFetch(){

         fetch('https://httpbin.org/get')

             .then(function(data){

                 return data.text();

             })

             .then((responseText) => {

                 alert("请求成功！");

                 this.setState({responseText})

                 console.log(responseText);

             })

             .catch((error) => {

                 alert("请求失败！");

             });

     }

 }

 //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'

     },

 });