React复习（9）

（1）react-redux

这是专门为react整合的reudx库
其中主要利用容器组件和UI组件
容器组件负责与redux通信，逻辑代码写在这里面
UI组件值负责呈现内容,其中的数据全都由props传递
下面是具体例子
只加了一个AppCountReactRedux.js，其他与上一篇笔记没区别

 （2）数字加减案例

//AppCountReactRedux.js
import {Component} from 'react'
import store from './store'
import {incrementAction,decrementAction} from './store/actionCreator'
import {connect,Provider} from 'react-redux'
import ProtoTypes from 'prop-types'

//1：定义UI组件
function Counter(props){
  const {value,increment,decrement} = props
  return(
    <div>
      Clicked:{value} times
      <button onClick={increment}>+</button>
      <button onClick={decrement}>-</button>
    </div>
  )
}
//注意检查参数
Counter.prototype = {
  value:ProtoTypes.number.isRequired,
  increment:ProtoTypes.func.isRequired,
}
//2：定义映射逻辑
//将dispatch，action和state映射到UI组件里
//映射state，state是传来的参数，返回值是对象
const mapStateProps = state =>({
  value :state.count
})
//映射dispatch，返回值是也是对象
const mapDispatchProps = dispatch =>({
  increment:()=>dispatch(incrementAction()),
  decrement:()=>dispatch(decrementAction())
})
//简写：store自动调用dispatch
// const mapDispatchProps ={
//   increment:()=>incrementAction(),
//   decrement:()=>decrementAction()
// }
//3：定义容器组件
//connect返回一个新的方法，这个方法接收一个组件Counter
//把这两个方法传进去，对Counter组件增强，返回一个新的容器组件Container
//可以理解为增强props
const Container = connect(mapStateProps,mapDispatchProps)(Counter)
class App extends Component {
  render() { 
    return (
      //redux提供的组件，传入store，实现各种功能
      <Provider store={store}>
        <Container/>
      </Provider>
    );
  }
}
export default App;

（3） 表单案例

//AppStudentForm.js
import { Component } from 'react'
import store from './store'
import { nameAction, ageAction, commitAction } from './store/actionCreator'
import { connect, Provider } from 'react-redux'

function StudentForm(props) {
  const { name, age, handleChangeName, handleChangeAge, handleCommit } = props
  return (
    <div style={{ margin: "20px" }}>
      <h1>name:{name}</h1>
      <h1>age:{age}</h1>
      name:<input type='text' onChange={handleChangeName}></input>
      age:<input type='text' onChange={handleChangeAge}></input>
      <button onClick={handleCommit}>commit</button>
    </div>
  )
}
const mapStateToProps = state => ({
  name: state.name,
  age: state.age
})
//映射dispatch，返回值是也是对象
const mapDispatchToProps = dispatch => ({
  //e是dom对象，通过e可以获取dom的属性和值，由payload接收
  handleChangeName: (e) => dispatch(nameAction(e.target.value)),
  handleChangeAge: (e) => dispatch(ageAction(e.target.value)),
  handleCommit: () => dispatch(commitAction())
})
const Container = connect(mapStateToProps, mapDispatchToProps)(StudentForm)
class App extends Component {
  render() {
    return (
      <Provider store={store}>
        <Container></Container>
      </Provider>
    )

  }
}
export default App;


//reducerStudentForm.js
import * as constant from './constant'
const defaultState = {
  name: '',
  age: ''
}
const reducerStudentForm = (state = defaultState, action) => {
  //let newState = JSON.parse(JSON.stringify(state))
  console.log(action);
  switch (action.type) {
    case constant.FORM_NAME:
      //与原来数据进行合并再返回新的对象
      // newState.name = action.payload
      // return newState
      return {...state,name:action.payload}
    case constant.FORM_AGE:
      // newState.age = action.payload
      // return newState
      return {...state,age:action.payload}
    case constant.FORM_COMMIT:
      //提交数据不再写到页面里
      //而是在reducer中利用中间件提交数据
      console.log('提交成功')
      return state
      //return { data: `name${state.name},age${state.age}` }
    default:
      return state
  }
}
export default reducerStudentForm


//actionCreator.js
//统一管理，增强action
//因为reducer不适合写副作用代码，所以都写到action里
import * as constant from './constant'
//数字加减
export const incrementAction = (payload) => {
  return {type :constant.INCREMENT,payload:payload}
}
export const decrementAction = () => ({type :constant.DECREMENT})
//学生表单
//这里的payload接收参数，供reducer使用
export const nameAction = (payload) => {
  return {type :constant.FORM_NAME,payload:payload}
}
export const ageAction = (payload) => {
  return {type :constant.FORM_AGE,payload:payload}
}
export const commitAction = () => {
  return {type :constant.FORM_COMMIT}
}

（4）Task多组件案例

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


//AppTask.js
import React from 'react'
import store from './store'
import {Provider} from 'react-redux'
import Container from './pages/Task'
function App(){
  return (
    <Provider store={store}>
      <Container />
    </Provider>
  )
}
export default App;


//src->pages->Task->index.js
import React from 'react';
import AddTask from './components/AddTask'
import TaskList from './components/TaskList'
import {connect} from 'react-redux'
//1：定义UI组件
function TaskMain(props){
  const {taskNum} = props
  return(
    <div>
      <h1>Today Tasks : {taskNum}</h1>
      <AddTask></AddTask>
      <TaskList></TaskList>
    </div>
  )
}
//2：定义映射逻辑
const mapState = (state)=>{
  return{
    taskNum:state.reducerTasks.tasks.length
  }
}
//3：定义容器
export default connect(mapState,null)(TaskMain)


//src->pages->Task->Components->AddTask.jsx
import { connect } from 'react-redux'
import { actionAddTask, actionSync } from '../../../store/actions/actionTasks'
function AddTask(props) {
  //syncTask是用来同步任务的
  const {content,syncTask,addTask} = props
  return (
    <div>
      <input type="text" value={content} onChange={syncTask} />
      <button onClick={addTask}>add task</button>
    </div>
  )
}
const mapState = state => {
  return {
    content: state.reducerTasks.content
  }
}
const mapDispatch = {
  syncTask: (e) => actionSync(e.target.value),
  addTask: () => actionAddTask()
}
export default connect(mapState, mapDispatch)(AddTask)


//src->pages->Task->Components->TaskItem.jsx
import { connect } from "react-redux";
import { actionDeleteTask } from "../../../store/actions/actionTasks";
function TaskItem({ index, task, date, deleteTask }) {
  return (
    <li >
      <span>{index + 1}--{task}--{date}</span>
      {/* 这么写的话deleteTask马上就会执行，会报错 */}
      {/* <button onClick={deleteTask}>delete</button> */}
      <button onClick={() => { deleteTask(index) }}>delete</button>
    </li>
  )
}
const mapDispatchToProps = {
  deleteTask: index => actionDeleteTask(index)
}
export default connect(null, mapDispatchToProps)(TaskItem);


//src->pages->Task->Components->TaskList.jsx
import TaskItem from './TaskItem'
import { connect } from "react-redux";
function TaskList(props) {
  const { tasks } = props
  return (
    <div>
      <ul>
        {
          tasks.map((item, index) => {
            return <TaskItem key={index} index={index} task={item.content} date={item.date} />
          })
        }
      </ul>
    </div>
  )
}
const mapState = state => {
  return {
    tasks: state.reducerTasks.tasks
  }
}
export default connect(mapState, null)(TaskList);


//store->index.js
import reducer from "./reducer/index.js";
import {createStore} from 'redux'
const store = createStore(reducer);
export default store;


//store->actionTypes.js
//维护常量
//counter
export const INCREMENT = 'INCREMENT'
export const DECREMENT = 'DECREMENT'
//studentForm
export const FORM_NAME = 'FORM_NAME'
export const FORM_AGE = 'FORM_AGE'
export const FORM_COMMIT = 'FORM_COMMIT'
// task
export const TASK_ADD = 'TASK_ADD'
export const TASK_SYNC = 'TASK_SYNC' 
export const DELETE_TASK = 'DELETE_TASK'


//actionTasks.js
import * as Type from '../actionTypes'
//同步任务内容
export const actionSync = (content)=>{
    return {type:Type.TASK_SYNC,payload:content}
}
//提交任务
export const actionAddTask = ()=>{
    return {type:Type.TASK_ADD}
}
//删除任务
export const actionDeleteTask = index => ({
  type: Type.DELETE_TASK,
  payload: index
})


//reducer->index.js
//合并reducer
import reducerForm from './reducerForm'
import reducerCounter from './reducerCounter'
import reducerTasks from './reducerTasks'
import { combineReducers } from 'redux'
let reducer = combineReducers({
    reducerCounter,
    reducerForm,
    reducerTasks
})
export default reducer


//reducer->reducerTasks.js
import * as Type from '../actionTypes'
//模拟数据
const tasks = [{
  content: "reading",
  date: new Date().toLocaleDateString()
}]
//初始化数据
const defaultState = {
  tasks: tasks,
  content: ''
}
//进行业务逻辑处理
const reducerTasks = (state = defaultState, action) => {
  switch (action.type) {
    case Type.TASK_SYNC:
      let content = action.payload
      return { ...state, content: content }
    case Type.TASK_ADD:
      //方案1
      //让state.tasks等于新的数组
      state.tasks = [...state.tasks]
      let task = { content: state.content, date: new Date().toLocaleDateString() }
      state.tasks.unshift(task)
      state.content = ''
      return { ...state }
    //方案2
    // let  newTasks =  [...state.tasks]
    // let task = {content:state.content,date:new Date().toLocaleDateString()}
    // newTasks.unshift(task)
    // return {content:'',tasks:newTasks}
    //方案3
    // let  newTasks =  [...state.tasks]
    // let task = {content:state.content,date:new Date().toLocaleDateString()}
    // newTasks.unshift(task)
    // state.tasks = newTasks
    // return {...state}
    case Type.DELETE_TASK:
      let index = action.payload;
      state.tasks = [...state.tasks];
      state.tasks.splice(index, 1); 
      return {...state};
    default:
      return state
  }
}
export default reducerTasks

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