1、目录结构

2、count/index.js

import React, {Component} from "react";
//引入store,用于获取数据
import store from '../../redux/store'
export default class Count extends Component {state = {count:store.getState()}componentDidMount() {//监测redux中的数据的变化，只要改变，就会调用renderstore.subscribe(()=>{this.setState({count:store.getState()})})}//加法increment=()=>{const {value} = this.selectNum//通知redux 改变store.dispatch({type:'increment',data:parseInt(value)})}//减法decrement=()=>{const {value} = this.selectNumstore.dispatch({type:'decrement',data:parseInt(value)})}//奇数加incrementIfOdd=()=>{const {value} = this.selectNumconst {count} = this.stateif(count%2!==0){store.dispatch({type:'increment',data:parseInt(value)})}}//异步加incrementAsync=()=>{const {value} = this.selectNumconst {count} = this.statesetTimeout(()=>{store.dispatch({type:'increment',data:parseInt(value)})},500)}render(){return(<div><h1>当前求和为：{store.getState()}</h1><select ref={(c)=>this.selectNum=c}><option value="1">1</option><option value="2">2</option><option value='3'>3</option></select>&nbsp;<button onClick={this.increment}>+</button>&nbsp;<button onClick={this.decrement}>-</button>&nbsp;<button onClick={this.incrementIfOdd}>当前求和为奇数在加</button>&nbsp;<button onClick={this.incrementAsync}>异步加</button>&nbsp;</div>);}}

3、redux/count_reducer.js

/*1.该文件是用于创建一个为count服务的reducer，reducer的本质就是一个函数2.reducer函数会接到两个参数，分别为：之前的状态(preState)，动作对象(action)*/
const initState = 0
export default function countReducer(preState=initState,action) {console.log('countReducer',preState,action)const {type,data} = action// 根据type决定如何加工数据switch (type){case 'increment':console.log('@')return preState + datacase 'decrement':return preState - datadefault:return preState}
}

/redux/store.js

/*该文件专门用于创建一个为Count组件服务的store对象*/
//引入createStore,专门创建redux中最为核心的store对象
import {createStore} from 'redux'
//引入cunter.redux.js文件
import countReducer from './count_reducer'
//暴露store
export default createStore(countReducer)

4、src/app.js

import React, {Component} from "react";
import Count from "./components/Count";
export default class App extends Component {render(){return(<div><Count></Count></div>);}
}

5、src/index.js

import React from "react";
import ReactDOM from 'react-dom'
import App from './App'
ReactDOM.render(<App/>,document.getElementById('root'))