这一个例子来自于某培训机构的视频，不得不说，讲的很清晰。例子也更容易理解redux的使用。

组件：

import React, { Component } from 'react'
//引入store，用于获取redux中保存状态
import store from '../../redux/store'

export default class Count extends Component {

	state = {carName:'奔驰c63'}

	/* componentDidMount(){
		//检测redux中状态的变化，只要变化，就调用render
		store.subscribe(()=>{
			this.setState({})
		})
	} */

	//加法
	increment = ()=>{
		const {value} = this.selectNumber
		store.dispatch({type:'increment',data:value*1})
	}
	//减法
	decrement = ()=>{
		const {value} = this.selectNumber
		store.dispatch({type:'decrement',data:value*1})
	}
	//奇数再加
	incrementIfOdd = ()=>{
		const {value} = this.selectNumber
		const count = store.getState()
		if(count % 2 !== 0){
			store.dispatch({type:'increment',data:value*1})
		}
	}
	//异步加
	incrementAsync = ()=>{
		const {value} = this.selectNumber
		setTimeout(()=>{
			store.dispatch({type:'increment',data:value*1})
		},500)
	}

	render() {
		return (
			<div>
				<h1>当前求和为：{store.getState()}</h1>
				<select ref={c => this.selectNumber = 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}>当前求和为奇数再加</button>&nbsp;
				<button onClick={this.incrementAsync}>异步加</button>&nbsp;
			</div>
		)
	}
}

redux文件夹

reducer.js

/* 
	1.该文件是用于创建一个为Count组件服务的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 //初始化状态
export default function countReducer(preState=initState,action){
	// console.log(preState);
	//从action对象中获取：type、data
	const {type,data} = action
	//根据type决定如何加工数据
	switch (type) {
		case 'increment': //如果是加
			return preState + data
		case 'decrement': //若果是减
			return preState - data
		default:
			return preState
	}
}

store.js

/* 
	该文件专门用于暴露一个store对象，整个应用只有一个store对象
*/

//引入createStore，专门用于创建redux中最为核心的store对象
import {createStore} from 'redux'
//引入为Count组件服务的reducer
import countReducer from './count_reducer'
//暴露store
export default createStore(countReducer)

页面效果