react native 各種居中

import React,{Component} from 'react';
import {View,Text} from 'react-native';

export default class Demo13Component extends Component{
    render(){
        return (
            <View>
                <View style={{height:100,width:100,backgroundColor:'#eee',alignItems:'center'}}>
                    <Text>水平居中</Text>
                </View>
                <View style={{height:100,width:100,backgroundColor:'green',justifyContent:'center'}}>
                    <Text>垂直居中</Text>
                </View>
                <View style={{height:100,width:100,backgroundColor:'red',alignItems:'center',justifyContent:'center'}}>
                    <Text>水平垂直居中</Text>
                </View>
            </View>
        )
    }
}