项目结构

准备工作

1）定义一个person组件，和count组件通过redux共享数据

2）为person组件编写：reducer ，action和contant常量

3）重点：Person的reducer和Count的reducer要用combineReducers进行合并，合并后的总状态

是一个对象

4）交给store的是总的reducer，最后注意在组件中取出状态的时候，记得取到位

代码展示

index.js

import React from 'react'
import ReactDOM from 'react-dom'
import App from './App.jsx'
import store from './redux/store'//为provider服务
import {Provider} from 'react-redux'

ReactDOM.render(
<Provider store= {store}>
  <App/>
</Provider>,
document.getElementById('root')
)

// 检测redeux中状态的改变，若redux的状态发生了改变，那么重新渲染App组件
//使用react-redux创建容器组件后，react-redux可以自己实现检测state中状态的改变，所以可以删除
//以下代码
// store.subscribe(() => {
//   ReactDOM.render(<App/>,document.getElementById('root'))
// })

App.jsx

import React, { Component } from 'react'
import Count from './containers/Count'
import Person from './containers/Person'

export default class App extends Component {
  render() {
    return (
      <div>
        <Count/>
        <hr/>
        <Person/>
      </div>
    )
  }
}

redux-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,applyMiddleware用于支持
//异步action的中间件
//combineReducers用于合并多个reducer
import {createStore,applyMiddleware,combineReducers} from 'redux'

//引入为Count组件服务的reducer
import countReducer from './reducers/count'

//引入为Person组件服务的reducer
import personReducer from './reducers/person'

//引入redux-thunk，用于支持异步action
import thunk from 'redux-thunk'

//汇总所有的reducer变为一个总的reducers
const allReducer = combineReducers({
  he:countReducer,
  rens:personReducer
})

export default createStore(allReducer, applyMiddleware(thunk))

redux-content.js

/*
  该文件是用于定义action对象中的type类型的常量值
  目的只有一个：防止程序员在编码的同时单次写错
*/

export const INCREMENT = 'increment'
export const DECREMENT = 'decrement'
export const ADD_PERSON = 'add_person'

redux-actions-count.jsx

/*
  该文件专门为count组件生成action对象
*/
import { INCREMENT, DECREMENT } from "../constant"
//完整写法
// function createIncrementAction(data) {
//   return {type:'increment', data }
// }
//简写形式
//同步action，就是值action的返回值是Object类型的一般对象
export const createIncrementAction = data =>( {type:INCREMENT, data })

//完整写法
// function createDecrementAction(data) {
//   return {type:'decrement', data}
// }
export const createDecrementAction = data =>( {type: DECREMENT, data })

//异步action，就是值action的返回值是函数，异步action一般都会调用同步action
//异步action不是必须要用的
export const createIncrementAsyncAction = (data, time) =>{
  return (dispatch) => {
    setTimeout(() => {
      dispatch(createIncrementAction(data))
    },time)
  }
}

redux-actions-person.js

import {ADD_PERSON} from '../constant'

//创建增加一个人的action对象
export const creatAddPersonAction = personObj => ({type:ADD_PERSON, data:personObj})

redux-reducers-count.js

/*
  1.该文件用于创建一个为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，分别是之前的state(状态)和action(动作对象)
*/
import { INCREMENT, DECREMENT } from "../constant";

const initState = 0
export default function countReducer(preState=initState, action) {
  console.log(preState, action);
  //从action对象中获取type, data
  const {type, data} = action
  //根据type类型决定如何加工
  switch (type) {
    case INCREMENT:// 如果是加
     return preState + data
    case DECREMENT:// 如果是减
      return preState - data
    default:
      return preState
  }
}

redux-reducers-person.js

import { ADD_PERSON } from "../constant"

//初始化人的列表
const initState = [{id:'001',name:'tom', age:18}]

export default function personReducer(preState=initState, action) {
  const {type,data} = action
  switch(type) {
    case ADD_PERSON:
      return [data, ...preState]// 若是添加一个人
    default:
      return preState
  }
}

containers-count-index.jsx

//引入CountUI组件
// import CountUI from '../../compoents/Count'

import React, { Component } from 'react'

//引入connect用于连接UI组件和redux
import {connect} from 'react-redux'
//引入action
import {
  createIncrementAction,
  createDecrementAction,
  createIncrementAsyncAction
} from '../../redux/actions/count'

//定义UI组件
class Count extends Component {
  state = {carName:'奔驰c63'}//  把状态交给reducer之后组件也可以有自己独用的状态


  increment = () => {
    const {value} = this.selectNum
    this.props.jia(value*1)

  }
  decrement = () => {
    const {value} = this.selectNum
    this.props.jian(value*1)
  }
  incrementOdd = () => {
    const {value} = this.selectNum
    if(this.props.count % 2 !== 0) {
      this.props.jia(value*1)
    }
  }
  incrementWait = () => {
    const {value} = this.selectNum
    this.props.jiaAsync(value*1,400)
  }
  render() {
    console.log('UI组件接收到的props是：',this.props);
    return (
      <div>
        <h2>我是Count组件,下方组件总人数是{this.props.renshu}</h2>
        <h3>当前求和为：{this.props.count}</h3>
        <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.incrementOdd}>当前求和为奇数再加</button>&nbsp;
        <button onClick= {this.incrementWait}>等一等再加</button>
      </div>
    )
  }
}

//使用connect()()创建并暴露一个Count容器组件
export default connect(
  state => ( {count:state.he,renshu:state.rens.length}), 
  //mapDispatchToProps的一般写法
  // dispatch => ({
  //   jia:number => dispatch(createIncrementAction(number)),
  //   jian:number => dispatch(createDecrementAction(number)),
  //   jiaAsync:(number,time) =>dispatch(createIncrementAsyncAction(number,time)) 
  // })

   //mapDispatchToProps的简写,dispatch由react-redux来完成,程序员工作中用这种方法
   {
    jia:createIncrementAction,
    jian:createDecrementAction,
    jiaAsync:createIncrementAsyncAction
   }
  )(Count)

containers-Person-index.jsx

import React, { Component } from 'react'
import {nanoid} from 'nanoid'
import {connect} from 'react-redux'
import {creatAddPersonAction} from '../../redux/actions/person'

class Person extends Component {
  addPerson = () => {
    const name = this.nameNode.value
    const age = this.ageNode.value
    const personObj = {id:nanoid(), name, age}
    this.props.jiayiren(personObj)
    this.nameNode.value = ''
    this.ageNode.value = ''
  }
  render() {
    return (
      <div>
        <h2>我是person组件,上方组件求和为{this.props.he}</h2>
        <input ref={c => this.nameNode = c} type="text" placeholder="请输入姓名"/>&nbsp;
        <input ref={c => this.ageNode = c} type="text" placeholder="请输入年龄"/>&nbsp;
        <button onClick= {this.addPerson}>添加</button>
        <ul>
         {
            this.props.yiduiren.map((p) => {
              return <li key={p.id}>{p.name}--{p.age}</li>
            })
         }
        </ul>
      </div>
    )
  }
}

export default connect(
  state => ({yiduiren:state.rens,he:state.he}),// 映射状态
  {jiayiren:creatAddPersonAction}//映射操作状态的方法
)(Person)