text: import React, {
      Component
  } from 'react';
  
  import {
      View,
      Text
  } from 'react-native';
  
  import MyScene from '../TrainDemo';
  
  //内置  Greeting
  //外置  MyScene
  
  export default class S3View extends Component {
    render() {
      return (
        <View>
          <Greeting />        
          <MyScene />
        </View>
      );
    }
  }
  
  class Greeting extends Component {
    render() {
      return (
        <Text>abcd</Text>
      );
    }
  }