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'
//引入actionCreator 专门创建action对象
import {createDecrementAction,createIncrementAction} from '../../redux/count_action'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)})store.dispatch(createIncrementAction(parseInt(value)))}//减法decrement=()=>{const {value} = this.selectNumstore.dispatch(createDecrementAction(parseInt(value)))}//奇数加incrementIfOdd=()=>{const {value} = this.selectNumconst {count} = this.stateif(count%2!==0){store.dispatch(createIncrementAction(parseInt(value)))}}//异步加incrementAsync=()=>{const {value} = this.selectNumsetTimeout(()=>{store.dispatch(createIncrementAction(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>);}}

2、redux/constant.js

/*该模块用于定义状态管理的常量名称,目的只有一个:便于管理的同时，防止程序员单词拼写错误
*/
export const INCREMENT = 'increment'
export const DECREMENT = 'decrement'

redux/count_action.js

/*该文件专门为Count组件生成action对象*/
import {INCREMENT,DECREMENT} from './constant'
// function createIncrementAction(data){
//     return {type:'increment',data}
// }
export const createIncrementAction = data=>({type:INCREMENT,data})
// function createDecrementAction(data){
//     return {type:'decrement',data}
// }
export const createDecrementAction = data=>({type:DECREMENT,data})// export default {
//     createIncrementAction,
//     createDecrementAction
// }

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)
*/
import {INCREMENT,DECREMENT} from "./constant";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)

3、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>);}
}

src/index.js

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