1.App.js代码如下

    import React, {

      Component

    } from 'react';

    import {

      Text,

      View,

      AppRegistry

    } from 'react-native';

    

    export default class HelloWorldApp extends Component {

      render() {

        return (

         

            Hello world! this is my HelloWorldApp

         

        );

      }

    }

    

    AppRegistry.registerComponent('HelloWorldApp', () => HelloWorldApp);

2.App.js代码截图如下：

3.运行结果截图：