@[toc]
改动的地方
注意点1：实现App和MyItem的删除功能，使用消息订阅与发布方式实现通信。
App.vue
import pubsub from 'pubsub-js'
methods: {
//删除一个todo
deleteTodo(_,id){
this.todos = this.todos.filter( todo => todo.id !== id )
}
}
mounted() {
this.$bus.$on('checkTodo',this.checkTodo)
this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)
},
beforeDestroy() {
this.$bus.$off('checkTodo')
pubsub.unsubscribe(this.pubId)
}
}MyItem.vue
import pubsub from 'pubsub-js'
methods: {
//删除
handleDelete(id){
if(confirm('确定删除吗？')){
//通知App组件将对应的todo对象删除
// this.deleteTodo(id)
// this.$bus.$emit('deleteTodo',id)
pubsub.publish('deleteTodo',id)
}
}案例全部代码
main.js
main.js
//引入Vue
import Vue from 'vue'
//引入App
import App from './App.vue'
//关闭Vue的生产提示
Vue.config.productionTip = false
//创建vm
new Vue({
el:'#app',
render: h => h(App),
beforeCreate() {
Vue.prototype.$bus = this
},
})App.vue
App.vue
<template>
<div id="root">
<div class="todo-container">
<div class="todo-wrap">
<MyHeader @addTodo="addTodo"/>
<MyList :todos="todos"/>
<MyFooter :todos="todos" @checkAllTodo="checkAllTodo" @clearAllTodo="clearAllTodo"/>
</div>
</div>
</div>
</template>
<script>
import pubsub from 'pubsub-js'
import MyHeader from './components/MyHeader'
import MyList from './components/MyList'
import MyFooter from './components/MyFooter'
export default {
name:'App',
components:{MyHeader,MyList,MyFooter},
data() {
return {
//由于todos是MyHeader组件和MyFooter组件都在使用，所以放在App中（状态提升）
todos:JSON.parse(localStorage.getItem('todos')) || []
}
},
methods: {
//添加一个todo
addTodo(todoObj){
this.todos.unshift(todoObj)
},
//勾选or取消勾选一个todo
checkTodo(id){
this.todos.forEach((todo)=>{
if(todo.id === id) todo.done = !todo.done
})
},
//删除一个todo
deleteTodo(_,id){
this.todos = this.todos.filter( todo => todo.id !== id )
},
//全选or取消全选
checkAllTodo(done){
this.todos.forEach((todo)=>{
todo.done = done
})
},
//清除所有已经完成的todo
clearAllTodo(){
this.todos = this.todos.filter((todo)=>{
return !todo.done
})
}
},
watch: {
todos:{
deep:true,
handler(value){
localStorage.setItem('todos',JSON.stringify(value))
}
}
},
mounted() {
this.$bus.$on('checkTodo',this.checkTodo)
this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)
},
beforeDestroy() {
this.$bus.$off('checkTodo')
pubsub.unsubscribe(this.pubId)
},
}
</script>
<style>
/*base*/
body {
background: #fff;
}
.btn {
display: inline-block;
padding: 4px 12px;
margin-bottom: 0;
font-size: 14px;
line-height: 20px;
text-align: center;
vertical-align: middle;
cursor: pointer;
box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
border-radius: 4px;
}
.btn-danger {
color: #fff;
background-color: #da4f49;
border: 1px solid #bd362f;
}
.btn-danger:hover {
color: #fff;
background-color: #bd362f;
}
.btn:focus {
outline: none;
}
.todo-container {
width: 600px;
margin: 0 auto;
}
.todo-container .todo-wrap {
padding: 10px;
border: 1px solid #ddd;
border-radius: 5px;
}
</style>MyHeader.vue
MyHeader.vue
<template>
<div class="todo-header">
<input type="text" placeholder="请输入你的任务名称，按回车键确认" v-model="title" @keyup.enter="add"/>
</div>
</template>
<script>
import {nanoid} from 'nanoid'
export default {
name:'MyHeader',
data() {
return {
//收集用户输入的title
title:''
}
},
methods: {
add(){
//校验数据
if(!this.title.trim()) return alert('输入不能为空')
//将用户的输入包装成一个todo对象
const todoObj = {id:nanoid(),title:this.title,done:false}
//通知App组件去添加一个todo对象
this.$emit('addTodo',todoObj,1,2,3)
//清空输入
this.title = ''
}
},
}
</script>
<style scoped>
/*header*/
.todo-header input {
width: 560px;
height: 28px;
font-size: 14px;
border: 1px solid #ccc;
border-radius: 4px;
padding: 4px 7px;
}
.todo-header input:focus {
outline: none;
border-color: rgba(82, 168, 236, 0.8);
box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(82, 168, 236, 0.6);
}
</style>MyList.vue
MyList.vue
<template>
<ul class="todo-main">
<MyItem
v-for="todoObj in todos"
:key="todoObj.id"
:todo="todoObj"
/>
</ul>
</template>
<script>
import MyItem from './MyItem'
export default {
name:'MyList',
components:{MyItem},
//声明接收App传递过来的数据
props:['todos']
}
</script>
<style scoped>
/*main*/
.todo-main {
margin-left: 0px;
border: 1px solid #ddd;
border-radius: 2px;
padding: 0px;
}
.todo-empty {
height: 40px;
line-height: 40px;
border: 1px solid #ddd;
border-radius: 2px;
padding-left: 5px;
margin-top: 10px;
}
</style>MyItem.vue
MyItem.vue
<template>
<li>
<label>
<input type="checkbox" :checked="todo.done" @change="handleCheck(todo.id)"/>
<!-- 如下代码也能实现功能，但是不太推荐，因为有点违反原则，因为修改了props -->
<!-- <input type="checkbox" v-model="todo.done"/> -->
<span>{{todo.title}}</span>
</label>
<button class="btn btn-danger" @click="handleDelete(todo.id)">删除</button>
</li>
</template>
<script>
import pubsub from 'pubsub-js'
export default {
name:'MyItem',
//声明接收todo
props:['todo'],
methods: {
//勾选or取消勾选
handleCheck(id){
//通知App组件将对应的todo对象的done值取反
// this.checkTodo(id)
this.$bus.$emit('checkTodo',id)
},
//删除
handleDelete(id){
if(confirm('确定删除吗？')){
//通知App组件将对应的todo对象删除
// this.deleteTodo(id)
// this.$bus.$emit('deleteTodo',id)
pubsub.publish('deleteTodo',id)
}
}
},
}
</script>
<style scoped>
/*item*/
li {
list-style: none;
height: 36px;
line-height: 36px;
padding: 0 5px;
border-bottom: 1px solid #ddd;
}
li label {
float: left;
cursor: pointer;
}
li label li input {
vertical-align: middle;
margin-right: 6px;
position: relative;
top: -1px;
}
li button {
float: right;
display: none;
margin-top: 3px;
}
li:before {
content: initial;
}
li:last-child {
border-bottom: none;
}
li:hover{
background-color: #ddd;
}
li:hover button{
display: block;
}
</style>MyFooter.vue
MyFooter.vue
<template>
<div class="todo-footer" v-show="total">
<label>
<!-- <input type="checkbox" :checked="isAll" @change="checkAll"/> -->
<input type="checkbox" v-model="isAll"/>
</label>
<span>
<span>已完成{{doneTotal}}</span> / 全部{{total}}
</span>
<button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
</div>
</template>
<script>
export default {
name:'MyFooter',
props:['todos'],
computed: {
//总数
total(){
return this.todos.length
},
//已完成数
doneTotal(){
//此处使用reduce方法做条件统计
/* const x = this.todos.reduce((pre,current)=>{
console.log('@',pre,current)
return pre + (current.done ? 1 : 0)
},0) */
//简写
return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0) ,0)
},
//控制全选框
isAll:{
//全选框是否勾选
get(){
return this.doneTotal === this.total && this.total > 0
},
//isAll被修改时set被调用
set(value){
// this.checkAllTodo(value)
this.$emit('checkAllTodo',value)
}
}
},
methods: {
/* checkAll(e){
this.checkAllTodo(e.target.checked)
} */
//清空所有已完成
clearAll(){
// this.clearAllTodo()
this.$emit('clearAllTodo')
}
},
}
</script>
<style scoped>
/*footer*/
.todo-footer {
height: 40px;
line-height: 40px;
padding-left: 6px;
margin-top: 5px;
}
.todo-footer label {
display: inline-block;
margin-right: 20px;
cursor: pointer;
}
.todo-footer label input {
position: relative;
top: -1px;
vertical-align: middle;
margin-right: 5px;
}
.todo-footer button {
float: right;
margin-top: 5px;
}
</style>本人其他相关文章链接
1.《基础篇第1章：vue2简介》包含Vue2知识点、个人总结的使用注意点及碰到的问题总结
2.《基础篇第2章：vue2基础》包含Vue2知识点、个人总结的使用注意点及碰到的问题总结
3.《进阶篇第3章：vue进阶-组件》包含组件、自定义事件、插槽、路由等等扩展知识点
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27.vue2基础组件通信案例练习：待办事项Todo-list案例练习
28.vue2基础组件通信案例练习：把案例Todo-list改写成本地缓存
29.vue2基础组件通信案例练习：把案例Todo-list改成使用自定义事件
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31.vue2基础组件通信案例练习：把案例Todo-list改成使用消息订阅与发布
32.vue2基础组件通信案例练习：把案例Todo-list新增编辑按钮
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