【Vue2】3-使用Vue脚手架

初始化脚手架

说明

具体步骤

模板项目的结构

关于不同版本的Vue

vue.config.js配置文件

ref属性

配置项props

mixin（混入）

插件

scoped样式

总结TodoList案例

webStorage（浏览器本地存储）

TodoList本地存储

组件的自定义事件

全局事件总线（GlobalEventBus）

TodoList事件总线

消息订阅与发布（pubsub）

TodoList_pubsub

nextTick

Vue封装的过渡与动画

TodoList_动画

初始化脚手架

说明

Vue脚手架是Vue官方提供的标准化开发工具（开发平台）

文档：https://cli.vuejs.org/zh/

具体步骤

1.全局安装@vue/cli

npm install -g @vue/cli

2.切换到要创建项目的目录，然后使用命令创建项目

vue create xxxx

3.启动项目

npm run serve

备注：

Vue脚手架隐藏了所有webpack相关的配置，若想查看具体的webpack配置，执行：

vue inspect > output.js

模板项目的结构

分析脚手架：

main.js：

/*** 该文件是整个项目的入口文件*///引入Vue
import Vue from 'vue'
//引入App组件，它是所有组件的父组件
import App from './App.vue'//关闭Vue的生产提示
Vue.config.productionTip = false//创建Vue实例对象vm
new Vue({el:'#app',//将App组件放入容器中render: h => h(App),
})

App.vue：

<template><div><img src="./assets/logo.png" alt="logo"><MySchool></MySchool><MyStudent></MyStudent></div>
</template><script>//引入组件import MySchool from './components/MySchool';import MyStudent from './components/MyStudent';export default {name:'App',components:{MySchool,MyStudent}}
</script><style></style>

MySchool.vue：

<template><!-- 组件的结构 --><div class="demo"><h2>学校名称：{{SchoolName}}</h2><h2>学校地址：{{address}}</h2><button @click="showName">点我提示学校名</button></div>
</template><script>//组件交互相关的代码（数据、方法等等）export default{name:'MySchool',data(){return{SchoolName:'尚硅谷1',address:'北京'}},methods: {showName(){alert(this.SchoolName)}}}</script><style>/* 组件的样式 */.demo{background-color: orange;}
</style>

MyStudent.vue：

<template><!-- 组件的结构 --><div><h2>学生姓名：{{StudentName}}</h2><h2>学校年龄：{{age}}</h2></div>
</template><script>//组件交互相关的代码（数据、方法等等）export default{name:'MyStudent',data(){return{StudentName:'张三',age:18}}}</script>

关于不同版本的Vue

vue.js与vue.runtime.xxx.js的区别：

(1)vue.js是完整版的Vue，包含：核心功能+模板解析器

(2)vue.runtime.xxx.js是运行版的Vue，只包含：核心功能，没有模板解析器

因为vue.runtime.xxx.js没有模板解析器，所以不能使用template配置项，需要使用render函数接收

到的createElement函数去指定具体内容

vue.config.js配置文件

使用vue inspect > output.js可以查看到Vue脚手架的默认配置

使用vue.config.js可以对脚手架进行个性化定制，详情见：https://cli.vuejs.org/zh

ref属性

被用来给元素或子组件注册引用信息（id的替代者）
应用在html标签上获取的是真实DOM元素，应用在组件标签上是组件实例对象（vc）
使用方式：

打标识：<h1 ref="xxx">......</h1>或<School ref="xxx"></School>

获取：this.$refs.xxx

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div><h1 v-text="msg" ref="title"></h1><button ref="btn" @click="showDOM">点我输出上方的DOM元素</button><School ref="sch"/></div>
</template>
<script>//引入School组件import School from './components/School'export default {name:'App',components:{School},data() {return {msg:'欢迎学习Vue'}},methods:{showDOM(){console.log(this.$refs.title) //真实DOM元素console.log(this.$refs.btn) //真实DOM元素console.log(this.$refs.sch) //School组件的实例对象（vc）}}}
</script>

School.vue：

<template><div class="school"><h2>学校名称：{{name}}</h2><h2>学校地址：{{address}}</h2></div>
</template>
<script>
export default {name:'School',data(){return{name:'尚硅谷1',address:'北京'}}
}
</script>
<style>.school{background-color: gray;}
</style>

配置项props

功能：让组件接收外部传过来的数据

1.传递数据：

<Demo name="xxx"/>

2.接收数据：

(1)第一种方式（只接收）：

props:['name']

(2)第二种方式（限制类型）：

props:{name:String
}

(3)第三种方式（限制类型、限制必要性、指定默认值）：

props:{name:{type:String, //类型required:true, //必要性default:'张三' //默认值}
}

备注：props是只读的，Vue底层会监测你对props的修改，如果进行了修改，就会发出警告，若业

务需求确实需要修改，那么请复制props的内容到data中一份，然后去修改data中的数据

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div><Student name="李四" sex="女" :age="18"/></div>
</template>
<script>//引入Student组件import Student from './components/Student.vue';export default {name:'App',components:{Student}}
</script>

Student.vue：

<template><div><h1>{{msg}}</h1><h2>学生姓名：{{name}}</h2><h2>学生性别：{{sex}}</h2><h2>学生年龄:{{myAge+1}}</h2><button @click="updateAge">尝试修改收到的年龄</button></div>
</template>
<script>
export default {name:'Student',data(){return{msg:'我是一个尚硅谷的学生',myAge:this.age}},methods:{updateAge(){this.myAge++}},//简单声明接收props:['name','sex','age'] //接收的同时对数据进行类型限制/* props:{name:String,age:Number,sex:String} *///接收的同时对数据进行类型限制+默认值的指定+必要性的限制/* props:{name:{type:String, //name的类型required:true //name是必要的},age:{type:Number,default:99 //默认值},sex:{type:String,required:true}} */}
</script>

mixin（混入）

功能：可以把多个组件共用的配置提取成一个混入对象

使用方式：

第一步：定义混入

{data(){},methods:{}......
}

第二步：使用混入

(1)全局混入：Vue.mixin(xxx)

(2)局部混入：mixins:['xxx']

mixin.js：

export const hunhe = {methods:{showName(){alert(this.name)}},mounted() {console.log('你好')}
}export const hunhe2 = {data() {return {x:100,y:200}}
}

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";
//引入混入
import { hunhe,hunhe2 } from "./mixin";Vue.config.productionTip = falseVue.mixin(hunhe)
Vue.mixin(hunhe2)//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div><School/><hr><Student/></div>
</template>
<script>//引入School组件import School from './components/School.vue';import Student from './components/Student.vue';export default {name:'App',components:{School,Student}}
</script>

School.vue：

<template><div><h2 @click="showName">学校名称：{{name}}</h2><h2>学校地址：{{address}}</h2></div>
</template><script>
// import { hunhe,hunhe2 } from '@/mixin';export default {name:'School',data(){return{name:'尚硅谷',address:'北京'}},// mixins:[hunhe,hunhe2],mounted(){console.log('你好！！！')}
}
</script>

Student.vue：

<template><div><h2 @click="showName">学生姓名：{{name}}</h2><h2>学生性别：{{sex}}</h2></div>
</template><script>
// import { hunhe } from '@/mixin';
export default {name:'Student',data(){return{name:'张三',sex:'男'}},// mixins:[hunhe]
}
</script>

插件

功能：用于增强Vue

本质：包含install方法的一个对象，install的第一个参数是Vue，第二个以后的参数是插件使用者传

递的数据

定义插件：

对象.install = function(Vue,options){//1.添加全局过滤器Vue.filter(...)//2.添加全局指令Vue.directive(...)//3.配置全局混入Vue.mixin(...)//4.添加实例方法Vue.prototype.$myMethod = function(){...}Vue.prototype.$myProperty = xxx
}

使用插件：Vue.use()

plugins.js：

export default {install(Vue){//全局过滤器Vue.filter('mySlice',function(value){return value.slice(0,4)})//全局指令（同过滤器）Vue.directive('fbind',{//指令与元素成功绑定时（一上来）bind(element,binding){element.value = binding.value},//指令所在元素被插入页面时inserted(element,binding){element.focus()},//指令所在的模板被重新解析时update(element,binding){element.value = binding.value}})//定义混入Vue.mixin({data(){return{x:100,y:200}}})//给Vue原型上添加一个方法（vm和vc都能使用）Vue.prototype.hello = ()=>(alert('你好'))}
}

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";
//引入插件
import plugins from "./plugins";Vue.config.productionTip = false//应用插件
Vue.use(plugins)//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div><School/><hr><Student/></div>
</template>
<script>//引入School组件import School from './components/School.vue';import Student from './components/Student.vue';export default {name:'App',components:{School,Student}}
</script>

School.vue：

<template><div><h2>学校名称：{{name | mySlice}}</h2><h2>学校地址：{{address}}</h2><button @click="test">点我测试hello方法</button></div>
</template><script>
export default {name:'School',data(){return{name:'尚硅谷atguigu',address:'北京'}},methods:{test(){this.hello()}}
}
</script>

Student.vue：

<template><div><h2>学生姓名：{{name}}</h2><h2>学生性别：{{sex}}</h2><input type="text" v-fbind:value="name"></div>
</template><script>export default {name:'Student',data(){return{name:'张三',sex:'男'}}
}
</script>

scoped样式

作用：让样式在局部生效，防止冲突

写法：<style scoped>

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div><School/><Student/></div>
</template>
<script>//引入School组件import School from './components/School.vue';import Student from './components/Student.vue';export default {name:'App',components:{School,Student}}
</script>

School.vue：

<template><div class="demo"><h2>学校名称：{{name}}</h2><h2>学校地址：{{address}}</h2></div>
</template><script>
export default {name:'School',data(){return{name:'尚硅谷atguigu',address:'北京'}}
}
</script><style scoped>.demo{background-color: skyblue}
</style>

Student.vue：

<template><div class="demo"><h2>学生姓名：{{name}}</h2><h2 class="atguigu">学生性别：{{sex}}</h2></div>
</template><script>export default {name:'Student',data(){return{name:'张三',sex:'男'}},}
</script><style lang="less" scoped>.demo{background-color: orange;.atguigu{font-size: 40px;}}
</style>

总结TodoList案例

组件化编码流程：

1.拆分静态组件：组件要按照功能点拆分，命名不要与html元素冲突

2.实现动态组件：考虑好数据的存放位置，数据是一个组件在用，还是一些组件在用：

(1)一个组件在用：放在组件自身即可

(2)一些组件在用：放在他们共同的父组件上（状态提升）

3.实现交互：从绑定事件开始

props适用于：

1.父组件 ===> 子组件通信

2.子组件 ===> 父组件通信（要求父先给子一个函数）

使用v-mode时要切记：v-model绑定的值不能是props传过来的值，因为props是不可以修改的

props传过来的若是对象类型的值，修改对象中的属性时Vue不会报错，但不推荐这样做

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div id="root"><div class="todo-container"><div class="todo-wrap"><MyHeader :addTodo="addTodo"/><MyList :todos="todos" :checkedTodo="checkedTodo" :deleteTodo="deleteTodo"/><MyFooter :todos="todos" :checkAllTodo="checkAllTodo" :clearAllTodo="clearAllTodo"/></div></div></div>
</template>
<script>import MyHeader from './components/MyHeader.vue';import MyList from './components/MyList.vue';import MyFooter from './components/MyFooter.vue';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:[{id:'001',title:'吃饭',done:true},{id:'002',title:'睡觉',done:false},{id:'003',title:'开车',done:true}]}},methods: {//添加一个todoaddTodo(todoObj){this.todos.unshift(todoObj)},//勾选or取消勾选一个todocheckedTodo(id){this.todos.forEach((todo)=>{if(todo.id == id) todo.done = !todo.done})},//删除一个tododeleteTodo(id){this.todos = this.todos.filter((todo)=>{return todo.id !== id})},//全选or取消全选checkAllTodo(done){this.todos.forEach((todo)=>{todo.done = done})},//清除所有已完成的todoclearAllTodo(){this.todos = this.todos.filter((todo)=>{return !todo.done})}}}
</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>

MyFooter.vue：

<template><div class="todo-footer" v-show="total"><label><input type="checkbox" :checked="isAll" @change="checkAll"/></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','checkAllTodo','clearAllTodo'],computed:{total(){return this.todos.length},doneTotal(){//第一种方式let i = 0this.todos.forEach((todo) => {if(todo.done) i++})return i//第二种方式// return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)},isAll(){return this.doneTotal === this.total && this.total > 0}},methods: {checkAll(e){this.checkAllTodo(e.target.checked)},clearAll(){this.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>

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',props:['addTodo'],data() {return {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组件添加一个todo对象this.addTodo(todoObj)//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>

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，但不推荐，违背原则，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>export default {name:'MyItem',//声明接收todo对象props:['todo','checkedTodo','deleteTodo'],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.checkedTodo(id)},//删除handleDelete(id){if(confirm('确定删除吗？')){this.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>

MyList.vue：

<template><ul class="todo-main"><MyItem v-for="todoObj in todos" :key="todoObj.id" :todo="todoObj" :checkedTodo="checkedTodo":deleteTodo="deleteTodo"/></ul>
</template><script>import MyItem from './MyItem.vue';export default {name:'MyList',components:{MyItem},props:['todos','checkedTodo','deleteTodo']}
</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>

webStorage（浏览器本地存储）

存储内容大小一般支持5MB左右（不同的浏览器可能不一样）

浏览器端通过Window.sessionStorage和Window.localStorage属性来实现本地存储机制

TodoList本地存储

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div id="root"><div class="todo-container"><div class="todo-wrap"><MyHeader :addTodo="addTodo"/><MyList :todos="todos" :checkedTodo="checkedTodo" :deleteTodo="deleteTodo"/><MyFooter :todos="todos" :checkAllTodo="checkAllTodo" :clearAllTodo="clearAllTodo"/></div></div></div>
</template>
<script>import MyHeader from './components/MyHeader.vue';import MyList from './components/MyList.vue';import MyFooter from './components/MyFooter.vue';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todoaddTodo(todoObj){this.todos.unshift(todoObj)},//勾选or取消勾选一个todocheckedTodo(id){this.todos.forEach((todo)=>{if(todo.id == id) todo.done = !todo.done})},//删除一个tododeleteTodo(id){this.todos = this.todos.filter((todo)=>{return todo.id !== id})},//全选or取消全选checkAllTodo(done){this.todos.forEach((todo)=>{todo.done = done})},//清除所有已完成的todoclearAllTodo(){this.todos = this.todos.filter((todo)=>{return !todo.done})}},watch:{todos:{deep:true,handler(value){localStorage.setItem('todos',JSON.stringify(value))}}}}
</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>

MyFooter.vue：

<template><div class="todo-footer" v-show="total"><label><input type="checkbox" :checked="isAll" @change="checkAll"/></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','checkAllTodo','clearAllTodo'],computed:{//总数total(){return this.todos.length},//已完成数doneTotal(){//第一种方式let i = 0this.todos.forEach((todo) => {if(todo.done) i++})return i//第二种方式（使用reduce方法做条件统计）// return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)},//控制全选框isAll(){return this.doneTotal === this.total && this.total > 0}},methods: {checkAll(e){this.checkAllTodo(e.target.checked)},clearAll(){this.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>

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',props:['addTodo'],data() {return {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组件添加一个todo对象this.addTodo(todoObj)//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>

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，但不推荐，违背原则，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>export default {name:'MyItem',//声明接收todo对象props:['todo','checkedTodo','deleteTodo'],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.checkedTodo(id)},//删除handleDelete(id){if(confirm('确定删除吗？')){this.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>

MyList.vue：

<template><ul class="todo-main"><MyItem v-for="todoObj in todos" :key="todoObj.id" :todo="todoObj" :checkedTodo="checkedTodo":deleteTodo="deleteTodo"/></ul>
</template><script>import MyItem from './MyItem.vue';export default {name:'MyList',components:{MyItem},props:['todos','checkedTodo','deleteTodo']}
</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>

组件的自定义事件

一种组件间通信的方式，适用于：子组件 ===> 父组件

使用场景：A是父组件，B是子组件，B想给A传数据，那么就要在A中给B绑定自定义事件（事件的

回调在A中）

绑定自定义事件：

第一种方式：在父组件中：

<Demo @atguigu="test"/>或<Demo v-on:atguigu="test"/>

第二种方式：

<Demo ref="demo"/>......mounted(){this.$refs.xxx.$on('atguigu',this.test)
}

若想让自定义事件只能触发一次，可以使用once修饰符或$once方法

触发自定义事件：this.$emit('atguigu',数据)

解绑自定义事件：this.$off('atguigu')

组件上也可以绑定原生DOM事件，需要使用native修饰符

注意：通过this.$refs.xxx.$on('atguigu',回调)绑定自定义事件时，回调要么配置在methods中，要

么用箭头函数，否则this指向会出问题

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),mounted() {setTimeout(()=>{this.$destroy()},3000)},
})

App.vue：

<template><div class="app"><h1>{{msg}},学生姓名是：{{studentName}}</h1><!-- 通过父组件给子组件传递函数类型的props实现：子给父传递数据 --><School :getSchoolName="getSchoolName"/><!-- 通过父组件给子组件绑定一个自定义事件实现：子给父传递数据（第一种写法：使用@或v-on） --><!-- <Student @atguigu="getStudentName" @demo="m1"/> --><!-- 通过父组件给子组件绑定一个自定义事件实现：子给父传递数据（第二种写法：使用ref） --><Student ref="student" @click.native="show"/></div>
</template>
<script>//引入School组件import School from './components/School.vue';import Student from './components/Student.vue';export default {name:'App',components:{School,Student},data() {return {msg:'你好',studentName:''}},methods:{getSchoolName(name){console.log('App收到了学校名：',name)},getStudentName(name){console.log('App收到了学生名：',name)this.studentName = name},m1(){console.log('demo事件被触发了')},show(){alert(123)}},mounted() {this.$refs.student.$on('atguigu',this.getStudentName) //绑定自定义事件// this.$refs.student.$once('atguigu',this.getStudentName) //绑定自定义事件（一次性）}}
</script><style scoped>.app{background-color: gray;padding: 5px}
</style>

School.vue：

<template><div class="school"><h2>学校名称：{{name}}</h2><h2>学校地址：{{address}}</h2><button @click="sendSchoolName">把学校名给App</button></div>
</template><script>
export default {name:'School',props:['getSchoolName'],data(){return{name:'尚硅谷',address:'北京'}},methods:{sendSchoolName(){this.getSchoolName(this.name)}}
}
</script><style scoped>.school{background-color: skyblue;padding: 5px;}
</style>

Student.vue：

<template><div class="student"><h2>学生姓名：{{name}}</h2><h2>学生性别：{{sex}}</h2><h2>当前求和为：{{number}}</h2><button @click="add">点我number++</button><button @click="sendStudentName">把学生名给App</button><button @click="unbind">解绑atguigu事件</button><button @click="death">销毁当前Student组件的实例（vc）</button></div>
</template><script>export default {name:'Student',data(){return{name:'张三',sex:'男',number:0}},methods: {add(){console.log('add回调被调用了')this.number++},sendStudentName(){//触发Student组件实例上的aiguigu事件this.$emit('atguigu',this.name)// this.$emit('demo')this.$emit('click')},unbind(){this.$off('atguigu') //解绑一个自定义事件// this.$off(['atguigu','demo']) //解绑多个自定义事件// this.$off() //解绑所有的自定义事件},death(){this.$destroy() //销毁了当前Student组件的实例，销毁后所有Student实例的自定义事件全都不奏效}},}
</script><style lang="less" scoped>.student{background-color: orange;padding: 5px;margin-top: 30px}
</style>

全局事件总线（GlobalEventBus）

一种组件间通信的方式，适用于任意组件间通信

安装全局事件总线：

new Vue({......beforeCreate(){Vue.prototype.$bus = this //安装全局事件总线，$bus就是当前应用的vm}......
})

使用事件总线：

1.接收数据：A组件想接收数据，则在A组件中给$bus绑定自定义事件，事件的回调留在A组件本身

methods:{demo(data){......}
}
......
mounted(){this.$bus.$on('xxxx',this.demo)
}

2.提供数据：this.$bus.$emit('xxxx',数据)

说明：最好在beforeDestroy钩子中，用$off去解绑当前组件所用到的事件

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),beforeCreate(){Vue.prototype.$bus = this //安装全局事件总线}
})

App.vue：

<template><div class="app"><h1>{{msg}}</h1><School/><Student/></div>
</template>
<script>//引入School组件import School from './components/School.vue';import Student from './components/Student.vue';export default {name:'App',components:{School,Student},data() {return {msg:'你好'}}}
</script><style scoped>.app{background-color: gray;padding: 5px}
</style>

School.vue：

<template><div class="school"><h2>学校名称：{{name}}</h2><h2>学校地址：{{address}}</h2></div>
</template><script>
export default {name:'School',props:['getSchoolName'],data(){return{name:'尚硅谷',address:'北京'}},mounted(){console.log('School',this)this.$bus.$on('hello',(data)=>{console.log('我是School组件，收到了数据',data)})},beforeDestroy() {this.$bus.$off('hello')},
}
</script><style scoped>.school{background-color: skyblue;padding: 5px;}
</style>

Student.vue：

<template><div class="student"><h2>学生姓名：{{name}}</h2><h2>学生性别：{{sex}}</h2><button @click="sendStudentName">把学生名给School组件</button></div>
</template><script>export default {name:'Student',data(){return{name:'张三',sex:'男'}},methods:{sendStudentName(){this.$bus.$emit('hello',this.name)}}
}
</script><style lang="less" scoped>.student{background-color: orange;padding: 5px;margin-top: 30px}
</style>

TodoList事件总线

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),beforeCreate(){Vue.prototype.$bus = this}
})

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 MyHeader from './components/MyHeader.vue';import MyList from './components/MyList.vue';import MyFooter from './components/MyFooter.vue';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todoaddTodo(todoObj){this.todos.unshift(todoObj)},//勾选or取消勾选一个todocheckedTodo(id){this.todos.forEach((todo)=>{if(todo.id == id) todo.done = !todo.done})},//删除一个tododeleteTodo(id){this.todos = this.todos.filter((todo)=>{return todo.id !== id})},//全选or取消全选checkAllTodo(done){this.todos.forEach((todo)=>{todo.done = done})},//清除所有已完成的todoclearAllTodo(){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('checkedTodo',this.checkedTodo)this.$bus.$on('deleteTodo',this.deleteTodo)},beforeDestroy(){this.$bus.$off('checkedTodo')this.$bus.$off('deleteTodo')}}
</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>

MyFooter.vue：

<template><div class="todo-footer" v-show="total"><label><input type="checkbox" :checked="isAll" @change="checkAll"/></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(){//第一种方式let i = 0this.todos.forEach((todo) => {if(todo.done) i++})return i//第二种方式（使用reduce方法做条件统计）// return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)},//控制全选框isAll(){return this.doneTotal === this.total && this.total > 0}},methods: {checkAll(e){// this.checkAllTodo(e.target.checked)this.$emit('checkAllTodo',e.target.checked)},clearAll(){// this.clearAllTodo()this.$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>

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 {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组件添加一个todo对象this.$emit('addTodo',todoObj)//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>

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，但不推荐，违背原则，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>export default {name:'MyItem',//声明接收todo对象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.checkedTodo(id)this.$bus.$emit('checkedTodo',id)},//删除handleDelete(id){if(confirm('确定删除吗？')){// this.deleteTodo(id)this.$bus.$emit('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>

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.vue';export default {name:'MyList',components:{MyItem},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>

消息订阅与发布（pubsub）

一种组件间通信的方式，适用于任意组件间通信

使用步骤：

1.安装pubsub：npm i pubsub-js

2.引入：import pubsub from 'pubsub-js'

3.接收数据：A组件想接收数据，则在A组件中订阅消息，订阅的回调留在A组件自身

methods:{demo(data){......}
}
......
mounted(){this.pid = pubsub.subscribe('xxx',this.demo) //订阅消息
}

4.提供数据：pubsub.publish('xxx',数据)

5.最好在beforeDestroy钩子中，用pubsub.unsubscribe(pid)去<span style="color:red">取消订阅</span>

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App)
})

App.vue：

<template><div class="app"><h1>{{msg}}</h1><School/><Student/></div>
</template>
<script>//引入School组件import School from './components/School.vue';import Student from './components/Student.vue';export default {name:'App',components:{School,Student},data() {return {msg:'你好'}}}
</script><style scoped>.app{background-color: gray;padding: 5px}
</style>

School.vue：

<template><div class="school"><h2>学校名称：{{name}}</h2><h2>学校地址：{{address}}</h2></div>
</template><script>
import pubsub from 'pubsub-js'
export default {name:'School',props:['getSchoolName'],data(){return{name:'尚硅谷',address:'北京'}},methods: {demo(msgName,data){console.log('有人发布了hello消息，hello消息的回调执行了',data,this)}},mounted(){// console.log('School',this)// this.$bus.$on('hello',(data)=>{// console.log('我是School组件，收到了数据',data)// })this.pubId = pubsub.subscribe('hello',this.demo)},beforeDestroy() {// this.$bus.$off('hello')pubsub.unsubscribe(this.pubId)},
}
</script><style scoped>.school{background-color: skyblue;padding: 5px;}
</style>

Student.vue：

<template><div class="student"><h2>学生姓名：{{name}}</h2><h2>学生性别：{{sex}}</h2><button @click="sendStudentName">把学生名给School组件</button></div>
</template><script>
import pubsub from 'pubsub-js'
export default {name:'Student',data(){return{name:'张三',sex:'男'}},methods:{sendStudentName(){// this.$bus.$emit('hello',this.name)pubsub.publish('hello',666)}}
}
</script><style lang="less" scoped>.student{background-color: orange;padding: 5px;margin-top: 30px}
</style>

TodoList_pubsub

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),beforeCreate(){Vue.prototype.$bus = this}
})

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.vue';import MyList from './components/MyList.vue';import MyFooter from './components/MyFooter.vue';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todoaddTodo(todoObj){this.todos.unshift(todoObj)},//勾选or取消勾选一个todocheckedTodo(id){this.todos.forEach((todo)=>{if(todo.id == id) todo.done = !todo.done})},//删除一个tododeleteTodo(_,id){this.todos = this.todos.filter((todo)=>{return todo.id !== id})},//全选or取消全选checkAllTodo(done){this.todos.forEach((todo)=>{todo.done = done})},//清除所有已完成的todoclearAllTodo(){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('checkedTodo',this.checkedTodo)this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)},beforeDestroy(){this.$bus.$off('checkedTodo')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>

MyFooter.vue：

<template><div class="todo-footer" v-show="total"><label><input type="checkbox" :checked="isAll" @change="checkAll"/></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(){//第一种方式let i = 0this.todos.forEach((todo) => {if(todo.done) i++})return i//第二种方式（使用reduce方法做条件统计）// return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)},//控制全选框isAll(){return this.doneTotal === this.total && this.total > 0}},methods: {checkAll(e){// this.checkAllTodo(e.target.checked)this.$emit('checkAllTodo',e.target.checked)},clearAll(){// this.clearAllTodo()this.$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>

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 {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组件添加一个todo对象this.$emit('addTodo',todoObj)//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>

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，但不推荐，违背原则，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对象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.checkedTodo(id)this.$bus.$emit('checkedTodo',id)},//删除handleDelete(id){if(confirm('确定删除吗？')){// 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>

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.vue';export default {name:'MyList',components:{MyItem},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>

nextTick

语法：this.$nextTick（回调函数）

作用：在下一次DOM更新结束后执行其指定的回调

什么时候用：当改变数据后，要基于更新后的新DOM进行某些操作时，要在nextTick所指定的回调函数中执行

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),beforeCreate(){Vue.prototype.$bus = this}
})

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.vue';import MyList from './components/MyList.vue';import MyFooter from './components/MyFooter.vue';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todoaddTodo(todoObj){this.todos.unshift(todoObj)},//勾选or取消勾选一个todocheckedTodo(id){this.todos.forEach((todo)=>{if(todo.id == id) todo.done = !todo.done})},//删除一个tododeleteTodo(_,id){this.todos = this.todos.filter((todo)=>{return todo.id !== id})},//全选or取消全选checkAllTodo(done){this.todos.forEach((todo)=>{todo.done = done})},//清除所有已完成的todoclearAllTodo(){this.todos = this.todos.filter((todo)=>{return !todo.done})},//更新一个todoupdateTodo(id,title){this.todos.forEach((todo)=>{if(todo.id == id) todo.title = title})}},watch:{todos:{deep:true,handler(value){localStorage.setItem('todos',JSON.stringify(value))}}},mounted() {this.$bus.$on('checkedTodo',this.checkedTodo)this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)this.$bus.$on('updateTodo',this.updateTodo)},beforeDestroy(){this.$bus.$off('checkedTodo')pubsub.unsubscribe(this.pubId)this.$bus.$off('updateTodo')}}
</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-edit {color: #fff;background-color: skyblue;border: 1px solid rgb(102, 159, 181);margin-right: 5px}.btn-edit:hover {color: #fff;background-color: rgb(102, 159, 181);}.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>

MyFooter.vue：

<template><div class="todo-footer" v-show="total"><label><input type="checkbox" :checked="isAll" @change="checkAll"/></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(){//第一种方式let i = 0this.todos.forEach((todo) => {if(todo.done) i++})return i//第二种方式（使用reduce方法做条件统计）// return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)},//控制全选框isAll(){return this.doneTotal === this.total && this.total > 0}},methods: {checkAll(e){// this.checkAllTodo(e.target.checked)this.$emit('checkAllTodo',e.target.checked)},clearAll(){// this.clearAllTodo()this.$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>

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 {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组件添加一个todo对象this.$emit('addTodo',todoObj)//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>

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，但不推荐，违背原则，修改了props --><!-- <input type="checkbox" v-model="todo.done"/> --><span v-show="!todo.isEdit">{{todo.title}}</span><input type="text" v-show="todo.isEdit" :value="todo.title" @blur="handleBlur(todo,$event)"ref="inputTitle"></label><button class="btn btn-danger" @click="handleDelete(todo.id)">删除</button><button class="btn btn-edit" @click="handleEdit(todo)" v-show="!todo.isEdit">编辑</button></li>
</template><script>import pubsub from 'pubsub-js'export default {name:'MyItem',//声明接收todo对象props:['todo'],methods: {//勾选or取消勾选handleCheck(id){//通知App组件将对应的todo对象的done值取反// this.checkedTodo(id)this.$bus.$emit('checkedTodo',id)},//删除handleDelete(id){if(confirm('确定删除吗？')){// this.deleteTodo(id)// this.$bus.$emit('deleteTodo',id)pubsub.publish('deleteTodo',id)}},//编辑handleEdit(todo){if(todo.hasOwnProperty('isEdit')){todo.isEdit = true}else{this.$set(todo,'isEdit',true)}this.$nextTick(function(){this.$refs.inputTitle.focus()})},//失去焦点回调（真正执行修改逻辑）handleBlur(todo,e){todo.isEdit = falseif(!e.target.value.trim()) return alert('输入不能为空！')this.$bus.$emit('updateTodo',todo.id,e.target.value)}}}
</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>

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.vue';export default {name:'MyList',components:{MyItem},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>

Vue封装的过渡与动画

作用：在插入、更新或移除DOM元素时，在合适的时候给元素添加样式类名

图示：

写法：

1.准备好样式：

(1)元素进入的样式：

v-enter：进入的起点

v-enter-active：进入过程中

v-enter-to：进入的终点

(2)元素离开的样式：

v-leave：离开的起点

v-leave-active：离开过程中

v-leave-to：离开的终点

2.使用<transition>包裹要过渡的元素，并配置name属性：

<transition name="hello"><h1 v-show="isShow">你好</h1>
</transition>

3.备注：若有多个元素需要过渡，则需要使用：<transition-group>，且每个元素都要指定key值

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),beforeCreate(){Vue.prototype.$bus = this}
})

App.vue：

<template><div><Demo/><Demo2/><Demo3/>      </div>
</template>
<script>import Demo from './components/Demo.vue'import Demo2 from './components/Demo2.vue'import Demo3 from './components/Demo3.vue'export default {name:'App',components:{Demo,Demo2,Demo3}}
</script>

Demo.vue：

<template><div><button @click="isShow = !isShow">显示/隐藏</button><transition name="hello" appear><h1 v-show="isShow">你好</h1></transition></div>
</template>
<script>export default {name:'Demo',data() {return {isShow:true}}}
</script><style>h1{background-color: orange;}.hello-enter-active{animation: atguigu 0.5s linear;}.hello-leave-active{animation: atguigu 0.5s linear reverse;}@keyframes atguigu {from{transform: translateX(-100%);}to{transform: translateX(0px);}}
</style>

Demo2.vue：

<template><div><button @click="isShow = !isShow">显示/隐藏</button><transition-group name="hello" appear><h1 v-show="!isShow" key="1">你好</h1><h1 v-show="isShow" key="2">尚硅谷</h1></transition-group></div>
</template>
<script>export default {name:'Demo',data() {return {isShow:true}}}
</script><style scoped>h1{background-color: orange;}/* 进入的起点，离开的终点 */.hello-enter,.hello-leave-to{transform: translateX(-100%);}.hello-enter-active,.hello-leave-active{transform: 0.5s linear;}/* 进入的终点，离开的起点 */.hello-enter-to,.hello-leave{transform: translateX(0);}</style>

Demo3.vue：

<template><div><button @click="isShow = !isShow">显示/隐藏</button><transition-group name="animate__animated animate__bounce" appearenter-active-class="animate__swing"leave-active-class="animate__backOutUp"><h1 v-show="!isShow" key="1">你好</h1><h1 v-show="isShow" key="2">尚硅谷</h1></transition-group></div>
</template>
<script>import 'animate.css'export default {name:'Demo',data() {return {isShow:true}}}
</script><style scoped>h1{background-color: orange;}</style>

TodoList_动画

main.js：

//引入Vue
import Vue from "vue";
//引入App
import App from "./App.vue";Vue.config.productionTip = false//创建vm
new Vue({el:'#app',render: h => h(App),beforeCreate(){Vue.prototype.$bus = this}
})

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.vue';import MyList from './components/MyList.vue';import MyFooter from './components/MyFooter.vue';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todoaddTodo(todoObj){this.todos.unshift(todoObj)},//勾选or取消勾选一个todocheckedTodo(id){this.todos.forEach((todo)=>{if(todo.id == id) todo.done = !todo.done})},//删除一个tododeleteTodo(_,id){this.todos = this.todos.filter((todo)=>{return todo.id !== id})},//全选or取消全选checkAllTodo(done){this.todos.forEach((todo)=>{todo.done = done})},//清除所有已完成的todoclearAllTodo(){this.todos = this.todos.filter((todo)=>{return !todo.done})},//更新一个todoupdateTodo(id,title){this.todos.forEach((todo)=>{if(todo.id == id) todo.title = title})}},watch:{todos:{deep:true,handler(value){localStorage.setItem('todos',JSON.stringify(value))}}},mounted() {this.$bus.$on('checkedTodo',this.checkedTodo)this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)this.$bus.$on('updateTodo',this.updateTodo)},beforeDestroy(){this.$bus.$off('checkedTodo')pubsub.unsubscribe(this.pubId)this.$bus.$off('updateTodo')}}
</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-edit {color: #fff;background-color: skyblue;border: 1px solid rgb(102, 159, 181);margin-right: 5px}.btn-edit:hover {color: #fff;background-color: rgb(102, 159, 181);}.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>

MyFooter.vue：

<template><div class="todo-footer" v-show="total"><label><input type="checkbox" :checked="isAll" @change="checkAll"/></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(){//第一种方式let i = 0this.todos.forEach((todo) => {if(todo.done) i++})return i//第二种方式（使用reduce方法做条件统计）// return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)},//控制全选框isAll(){return this.doneTotal === this.total && this.total > 0}},methods: {checkAll(e){// this.checkAllTodo(e.target.checked)this.$emit('checkAllTodo',e.target.checked)},clearAll(){// this.clearAllTodo()this.$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>

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 {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组件添加一个todo对象this.$emit('addTodo',todoObj)//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>

MyItem.vue：

<template><transition name="todo" appear><li><label><input type="checkbox" :checked="todo.done" @change="handleCheck(todo.id)"/><!-- 如下代码也能实现功能，但不推荐，违背原则，修改了props --><!-- <input type="checkbox" v-model="todo.done"/> --><span v-show="!todo.isEdit">{{todo.title}}</span><input type="text" v-show="todo.isEdit" :value="todo.title" @blur="handleBlur(todo,$event)"ref="inputTitle"></label><button class="btn btn-danger" @click="handleDelete(todo.id)">删除</button><button class="btn btn-edit" @click="handleEdit(todo)" v-show="!todo.isEdit">编辑</button></li></transition>
</template><script>import pubsub from 'pubsub-js'export default {name:'MyItem',//声明接收todo对象props:['todo'],methods: {//勾选or取消勾选handleCheck(id){//通知App组件将对应的todo对象的done值取反// this.checkedTodo(id)this.$bus.$emit('checkedTodo',id)},//删除handleDelete(id){if(confirm('确定删除吗？')){// this.deleteTodo(id)// this.$bus.$emit('deleteTodo',id)pubsub.publish('deleteTodo',id)}},//编辑handleEdit(todo){if(todo.hasOwnProperty('isEdit')){todo.isEdit = true}else{this.$set(todo,'isEdit',true)}this.$nextTick(function(){this.$refs.inputTitle.focus()})},//失去焦点回调（真正执行修改逻辑）handleBlur(todo,e){todo.isEdit = falseif(!e.target.value.trim()) return alert('输入不能为空！')this.$bus.$emit('updateTodo',todo.id,e.target.value)}}}
</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;}.todo-enter-active{animation: atguigu 0.5s linear;}.todo-leave-active{animation: atguigu 0.5s linear reverse;}@keyframes atguigu {from{transform: translateX(100%);}to{transform: translateX(0px);}}
</style>

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.vue';export default {name:'MyList',components:{MyItem},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>