React中消息订阅与发布(PubSubJS)——两个组件之间通信

结合案例：github搜索案例

• 结果如下图
  

1.父容器代码

import React, { Component } from 'react'
import Search from './components/Search'
import List from './components/List'
export default class App extends Component {
	render() {
		return (
			<div className="container">
				<Search/>
				<List/>
			</div>
		)
	}
}
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2.搜索Search子模块代码(发布消息)

import React, { Component } from 'react'
import PubSub from 'pubsub-js'
import axios from 'axios'

export default class Search extends Component {

	search = ()=>{
		//获取用户的输入(连续解构赋值+重命名)
		const {keyWordElement:{value:keyWord}} = this
		//发送请求前通知List更新状态
		PubSub.publish('atguigu',{isFirst:false,isLoading:true})
		//发送网络请求
		axios.get(`/api1/search/users?q=${keyWord}`).then(
			response => {
				//请求成功后通知List更新状态
				PubSub.publish('atguigu',{isLoading:false,users:response.data.items})
			},
			error => {
				//请求失败后通知App更新状态
				PubSub.publish('atguigu',{isLoading:false,err:error.message})
			}
		)
	}

	render() {
		return (
			<section className="jumbotron">
				<h3 className="jumbotron-heading">搜索github用户</h3>
				<div>
					<input ref={c => this.keyWordElement = c} type="text" placeholder="输入关键词点击搜索"/>&nbsp;
					<button onClick={this.search}>搜索</button>
				</div>
			</section>
		)
	}
}

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3.展示Lisi子模块代码(订阅消息)

import React, { Component } from 'react'
import PubSub from 'pubsub-js'
import './index.css'

export default class List extends Component {

	state = { //初始化状态
		users:[], //users初始值为数组
		isFirst:true, //是否为第一次打开页面
		isLoading:false,//标识是否处于加载中
		err:'',//存储请求相关的错误信息
	} 

	componentDidMount(){
		this.token = PubSub.subscribe('atguigu',(_,stateObj)=>{
			this.setState(stateObj)
		})
	}

	componentWillUnmount(){
		PubSub.unsubscribe(this.token)
	}

	render() {
		const {users,isFirst,isLoading,err} = this.state
		return (
			<div className="row">
				{
					isFirst ? <h2>欢迎使用，输入关键字，随后点击搜索</h2> :
					isLoading ? <h2>Loading......</h2> :
					err ? <h2 style={{color:'red'}}>{err}</h2> :
					users.map((userObj)=>{
						return (
							<div key={userObj.id} className="card">
								<a rel="noreferrer" href={userObj.html_url} target="_blank">
									<img alt="head_portrait" src={userObj.avatar_url} style={{width:'100px'}}/>
								</a>
								<p className="card-text">{userObj.login}</p>
							</div>
						)
					})
				}
			</div>
		)
	}
}
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发布订阅分析

• 在Search子模块中发布消息，用PubSub.publish中进行发布消息，在List子模块中订阅消息，拿到数据进行展示
• 使用步骤
  • 工具库: PubSubJS
  • 下载: npm install pubsub-js --save
  • 使用

    1)import PubSub from 'pubsub-js' //引入
    2)PubSub.subscribe('delete', function(data){ }); //订阅
    3)PubSub.publish('delete', data) //发布消息
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