React-Native TabBarIOS的学习

1.项目目录结构:

2.代码实现:
(1) index.ios.js

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 * @flow
 */

import React, { Component } from 'react';
import FirstVC from './FirstVC.js'
import SecondVC from './SecondVC.js'
import ThirdVC from './ThirdVC.js'

import {
  AppRegistry,
  StyleSheet,
  Text,
  View,
    TabBarIOS,
} from 'react-native';

export default class RN extends Component {

  constructor(props){
      super(props)
      this.state= {
          selectedTab: '图书',
      }
  }


  render() {
    return (

        /**
            * TabBar 默认的属性
            * barTintColor: tabBar的背景色
            * //指定item的位置
            * itemPositioning是个枚举:fill, center, auto
            * translucent: bool 是否要半透明
            * style:是个View类型
            /**
         /**
         * tintColorItem未选中时的颜色
         */
            unselectedTintColor="yellow"
            //Item选中的颜色
            tintColor="white"
            //tabBar的背景颜色
            barTintColor= 'darkslateblue'
            //itemPositioning= 'auto'
            translucent= {true}
            >
          '首页'
              /**
              * badge: string,number
              * 角标: 测试可以显示红色的是七位,数字无限制
              */
              badge="99"
              /**
              * systemIcon: 枚举 ('bookmarks', 'contacts', 'downloads', 'favorites', 'featured', 'history', 'more', 'most-recent', 'most-viewed', 'recents', 'search', 'top-rated')
              * 设置了此属性,会覆盖我们自定义的
              */
              //systemIcon = 'bookmarks'
              //引用Xcode里面的Images.xcassets
              //icon = {require('image!book')}
              //引用外部的img文件夹
              icon = {require('./img/book.png')}
              //选中的图片
              selectedIcon = {require('./img/movie.png')}
              selected={this.state.selectedTab === '图书'}
              //标签被选中时会调用,
              onPress={() => {
                this.setState({
                    selectedTab: '图书'
                 });
              }}
              >
              
          

          '电影'
              icon = {require('./img/movie.png')}
              selected = {this.state.selectedTab === '电影'}
              onPress={() => {
            this.setState({
              selectedTab: '电影'
            });
              }}
              >
             
          

          '音乐'
              //icon = {require('./img/music.png')}
              selected = {this.state.selectedTab === '音乐'}
              onPress={() => {
            this.setState({
              selectedTab: '音乐'
            });
              }}
              >
             
          

        
    );
  }
}

const styles = StyleSheet.create({

});

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

(2)FirstVC.js

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

export default class RN extends Component {

    render() {
        return(
            1,justifyContent:'center',alignItems:'center'}}>
                20}}>123
            
        )
    }
}

(3)SecondVC.js

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

export default class RN extends Component {

    render() {
        return(
            
                19}}>我的首秀
            
        )
    }
}
const styles = StyleSheet.create({
    textCenter:{
        flex:1,
        justifyContent:'center',
        alignItems:'center',
        backgroundColor:'red',
        //alignSelf:'center',
    }
});

(3)ThirdVC.js

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

export default class RN extends Component {

    render() {
        return(
            1, width: 100, height:100,backgroundColor:'green',alignItems:'center',justifyContent:'center'}}>
                90909090
            
        )
    }
}

效果图: