react如何实现todolist的增删改查

这期内容当中小编将会给大家带来有关react如何实现todolist的增删改查，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。

以todolist为例

目录如下

app.js

 import React, {  PureComponent } from 'react'import Input from './components/Input'import List from './components/List'import Total from './components/Total'import Mask from './components/Mask'import { bus as $bus } from './components/bus'import './App.css'export default class App extends PureComponent {  constructor() {    super()    this.state = {      flag: false,      list: [        {          id: 1,          content: '哈哈哈',          checked: false        },        {          id: 7,          content: '哈哈哈',          checked: false        },        {          id: 5,          content: '哈哈哈',          checked: false        },      ],      checkAll: false,      selectLength: 0,      item: {}    }  }  // 全选全不选  checkAllHandler(checked) {    console.log("checked",checked);    const { list } = this.state    const newList = list.map(item =>{      return {...item,checked}    })    this.setState({list:newList,checkAll: checked},()=>{      this.doneLenth()    })  }  // 单选单不选  checkHandler =(id,checked)=> {    const { list } = this.state    const newList = list.map(item => {      return item.id === id ? {...item,checked} : item    })    let checkAll = newList.length && newList.every(item => item.checked)    this.setState(() => ({list: newList,checkAll}),()=>{      this.doneLenth()    })  }  // 添加   addHandler = (obj)=>{    let { list } = this.state;    let newList = [...list,obj]    console.log('newList===='+newList)    this.setState({      list: newList,    },()=>{      this.doneLenth()    })  }   // 搜索  searchHandler=(content)=>{    console.log("content",content);    let { list } = this.state;    let newList = list.filter(item => item.content.includes(content))    this.setState({      list: newList    },()=>{      this.doneLenth()    })  }  // 删除  delHandler = (id)=> {    console.log("id",id);    const { list } = this.state    const newList = list.filter(item => item.id !=id)    let checkAll = newList.length && newList.every(item => item.checked)    this.setState(() => ({list: newList,checkAll}),()=>{      this.doneLenth()    })  }  // 编辑  editHandler = (items)=>{    this.setState({      item: items    })  }  // 更新  update = (content)=>{    const { list,item } = this.state    let obj = Object.assign(item,{content})    const newList = list.map(v =>{      if(v.id === obj.id) {        v = {...obj}      }      return v    })    this.setState({      list: newList,      item: obj    })  }  // 已完成   doneLenth=()=> {    const { list } = this.state    const newList = list.filter(item => item.checked)    let selectLength = newList.length    setTimeout(()=>{      this.setState({        selectLength      })    })  }  // 挂载  componentDidMount() {    this.unSubscribe = $bus.addListener("getFlag",(flag)=>{      this.setState({flag})    })    this.unSubscribe1 = $bus.addListener("sendValue",(obj)=>{     this.addHandler(obj)    })    this.unSubscribe2 = $bus.addListener("searchValue",(value)=>{     this.searchHandler(value)    })    this.unSubscribe3 = $bus.addListener("getItem",(item)=>{     this.editHandler(item)    })    this.unSubscribe4 = $bus.addListener("update",(content)=>{     this.update(content)    })  }  // 卸载  componentWillUnmount() {    $bus.removeListener(this.unSubscribe)    $bus.removeListener(this.unSubscribe1)    $bus.removeListener(this.unSubscribe2)    $bus.removeListener(this.unSubscribe3)    $bus.removeListener(this.unSubscribe4)  }  render() {    let { flag, list,checkAll,selectLength } = this.state    return (      
        {/* 输入框 */}                {/* 列表 */}                {/* 统计 */}                {/* 编辑弹框 */}        { flag ?  : ''}      
    )  }}

Input.js

import React, { Component } from 'react'import { bus as $bus } from './bus'export default class Input extends Component {  constructor() {    super()    this.state = {      value:""    }  }  changeHandler = (e)=>{    this.setState({      value: e.target.value    })    console.log("this.state.value",this.state.value);  }  // 添加  addHandler = ()=>{    let { value } = this.state;    let obj = {      id: Date.now(),      content: value,      done: false    }    if(value) {      $bus.emit("sendValue",obj)    } else {      console.log("请输入")    }  }  // 搜索  searchHandler = ()=>{    console.log("搜索");    let { value } = this.state;    if(!value) return console.log("请输入");    $bus.emit("searchValue",value)  }  render() {    let { value } = this.state    return (      <>        
                    添加          搜索        
          )  }}

List.js

import React, { Component } from 'react'import Item from './Item'import PropTypes from 'prop-types'export default class List extends Component {  static propTypes = {                list:PropTypes.array.isRequired,        }  render() {    let { list,checkHandler,checkAllHandler,delHandler } = this.props;    console.log("list",list);    return (      
        {          list.map(item => ())        }      
    )  }}

Item.js

import React, { Component } from 'react'import { bus as $bus } from './bus'export default class Item extends Component {  constructor(props) {    super(props)    this.state = {}  }  changeHandler = (id)=>{    let { checkHandler } = this.props;    return (e)=>{      checkHandler(id,e.target.checked)    }  }  removeHandler(){    let { delHandler } = this.props;    delHandler(arguments[0])  }  editHadnler = (item)=>{    $bus.emit("getFlag",true)    localStorage.setItem("obj",JSON.stringify(item))    $bus.emit("getItem",item)  }  render() {    let { item } = this.props;    return (      
                
          {item.content}        
         this.editHadnler(item)}>编辑        删除      
    )  }}

Total.js

import React, { Component } from 'react'export default class Total extends Component {  constructor() {    super()    this.changeAllHandler = this.changeAllHandler.bind(this)  }  changeAllHandler(e) {    let { checkAllHandler } = this.props    checkAllHandler(e.target.checked)  }  render() {    let { checkAll,selectLength } = this.props;    return (      
                
已完成{selectLength} 全部4
      
    )  }}

Mask.js（弹窗）

import React, { Component } from 'react'import { bus as $bus } from './bus'export default class mask extends Component {  constructor() {    super()    this.state = {      value: ''    }  }  closeMask = ()=>{ // 关闭弹窗    $bus.emit("getFlag",false)  }  updateHandler = ()=>{    $bus.emit("getFlag",false)    $bus.emit("update",this.state.value)  }  onChange = (e) =>{    this.setState({      value: e.target.value    })  }  componentDidMount() {    let obj = JSON.parse(localStorage.getItem("obj"))    this.setState({      value: obj.content    })  }  render() {    let { value } = this.state    return (      
        
        
          
            编辑            x          
          
                      
          
            
更新
            
取消
          
        
      
      
    )  }}

bus.js

 yarn add -D eventsimport { EventEmitter } from 'events'export const bus = new EventEmitter() // 导出bus实例

App.css

* {  margin: 0;  padding: 0;}input,button {  outline: none;  border: 0;}ul>li {  list-style: none;}.container {  width: 400px;  height: 500px;  margin: 10px auto auto;  padding: 20px;  box-sizing: border-box;  color: #3333;  border: 1px solid;  overflow: hidden;}.input {  width: 100%;  height: 30px;  display: flex;}input {  width: 100%;  height: 100%;  border: 1px solid #e1e1e1;  box-sizing: border-box;  border-radius: 4px;  padding: 0 10px;}input::placeholder {  color: #e1e1e1;}input:focus {  border: 1px solid #0096e6;}.task-list {  width: 100%;  display: flex;  flex-flow: column wrap;  margin-top: 10px;}.task-list li {  display: flex;  height: 40px;  justify-content: center;  align-items: center;  padding: 0 10px;  background-color: #eef0f4;  margin-bottom: 10px;  overflow: hidden;  text-overflow: ellipsis;  white-space: nowrap;}.task-list li input[type^="checkbox"] {  width: 15px;  height: 15px;  border: 1px solid #e1e1e1;  cursor: pointer;  flex-shrink: 0;}.task-list li .content {  flex: 1;  margin-left: 10px;}.btn {  flex-shrink: 0;  display: flex;  align-items: center;  height: 30px;  justify-content: center;  padding: 5px 10px;  text-align: center;  cursor: pointer;  border-radius: 4px;  color: #fff;  letter-spacing: 2px;  margin: 0 5px;  box-sizing: border-box;  font-size: 16px;}.btn-success {  background-color: #0f0;}.btn-danger {  background-color: #f00;}.btn-primary {  background-color: #0096e6;}.task-done {  width: 100%;  height: 40px;  line-height: 40px;  display: flex;  align-items: center;  background-color: #eef0f4;  padding-left: 10px;  box-sizing: border-box;  margin-top: 30px;}.task-done input {  width: 15px;  height: 15px;  border: 1px solid #e1e1e1;  cursor: pointer;  flex-shrink: 0;  margin-right: 10px;}.single-number {  color: #333;  margin-left: 5px;}.all-number {  color: red;  margin-left: 5px;}.mm-mask{  position:fixed;  top:0;  left:0;  right:0;  bottom:0;  background:rgba(0,0,0,0.5);}.mm-modal{  width:350px;  position:absolute;  top:50%;  left:50%;  transform:translate(-50%,-50%);  z-index:1000;  background:#ffffff;  border-radius:4px;  color:#333333;}.mm-title {  height:50px;  line-height:50px;  display:flex;  justify-content:space-between;  border-bottom:1px solid #e1e1e1;  box-sizing:border-box;  font-size:20px;}.mm-edit{  text-indent:20px;}.mm-close{  margin-right:20px;  font-family:consals;  cursor:pointer;}.mm-content{  padding:0 20px;  margin-bottom:20px;}.mm-content input{  width:100%;  height:30px;  line-height:30px;  text-indent:20px;  border-radius:4px;  margin-top:20px;  border:1px solid #666;  box-sizing:border-box;}.mm-content input:hover{  border:1px solid #0096e6;}.mm-content input:last-child{  text-indent:5px;}.mm-box-btn{  display:flex;}.mm-update,.mm-cancel{  width:80px;  height:30px;  line-height:30px;  text-align: center;  cursor:pointer;  background:#0096e6;  color:#ffffff;  user-select:none;  border-radius:4px;  margin:0 20px 50px;}.mm-update{  margin-right:10px;}.d-none {  display: none;}.d-block {  display: block;}

上述就是小编为大家分享的react如何实现todolist的增删改查了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注行业资讯频道。