【Vue 自定义事件】

组件的自定义事件

一种组件间通讯的方式，适用于：子组件 —> 父组件

绑定自定义事件

第一种方式:在父组件中写单标签1.<Demo @事件名="方法">2.<Demo v-on:事件名="方法"/>第二种方式:使用ref绑定(配置在生命周期中)this.$ refs.demo.$on(‘事件名’,方法)<Demo ref="demo">例(2)配置在生命周期中:mounted() {this.$refs.demo.$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

触发事件

触发自定义事件 this. $emit('事件名',数据)

解绑事件

解绑自定义事件 this. $off('事件名')

绑定原生事件

组件上也可以绑定原生事件
需要使用native修饰符
如： @click.native="show"

上面绑定自定义事件，即使绑定的是原生事件也会被人为是自定义的，需要加native,加了后就将此事件给组件的根元素

注意：
通过"this.r e f s . x x x . refs.xxx.refs.xxx.on(‘事件名’,回调函数)"
绑定自定义事件时，回调函数要么配置在'methods'中，要么用箭头函数，
否则this指向会出问题 src/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>import Student from './components/Student'import School from './components/School'export default {name:'App',components:{School,Student},data() {return {msg:'你好啊！',studentName:''}},methods: {getSchoolName(name){console.log('App收到了学校名：',name)},getStudentName(name,...params){console.log('App收到了学生名：',name,params)this.studentName = name},m1(){console.log('demo事件被触发了！')},show(){alert(123)}},mounted() {//绑定自定义事件this.$refs.student.$on('atguigu',this.getStudentName)//绑定自定义事件（一次性）this.$refs.student.$once('atguigu',this.getStudentName) },}
</script><style scoped>//样式.app{background-color: gray;padding: 5px;}
</style>

src/components/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="sendStudentlName">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++},sendStudentlName(){//触发Student组件实例身上的atguigu事件this.$emit('atguigu',this.name,666,888,900)// this.$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: pink;padding: 5px;margin-top: 30px;}
</style>

src/components/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>

使用自定义事件优化Todo-List

src/App.vue

<template><div id="root"><div class="todo-container"><div class="todo-wrap"><MyHeader @addTodo="addTodo"/><MyList :todos="todos" :checkTodo="checkTodo" :deleteTodo="deleteTodo"/><MyFooter :todos="todos" @checkAllTodo="checkAllTodo" @clearAllTodo="clearAllTodo"/></div></div></div>
</template><script>import MyHeader from './components/MyHeader'import MyList from './components/MyList'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todocheckTodo(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 => 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>

src/components/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titletitle:''}},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>

src/components/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>

使用自定义事件优化Todo-List

src/App.vue

<template><div id="root"><div class="todo-container"><div class="todo-wrap"><MyHeader @addTodo="addTodo"/><MyList :todos="todos" :checkTodo="checkTodo" :deleteTodo="deleteTodo"/><MyFooter :todos="todos" @checkAllTodo="checkAllTodo" @clearAllTodo="clearAllTodo"/></div></div></div>
</template><script>import MyHeader from './components/MyHeader'import MyList from './components/MyList'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todocheckTodo(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 => 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>

src/components/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titletitle:''}},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.$emit('addTodo',todoObj,1,2,3)//清空输入this.title = ''}},}
</script><style scoped>/*header*/.todo-header input {width: 560px;height: 28px;font-size: 14px;border: 1px solid #ccc;border-radius: 4px;padding: 4px 7px;}.todo-header input:focus {outline: none;border-color: rgba(82, 168, 236, 0.8);box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(82, 168, 236, 0.6);}
</style>src/components/MyFooter<template><div class="todo-footer" v-show="total"><label><!-- <input type="checkbox" :checked="isAll" @change="checkAll"/> --><input type="checkbox" v-model="isAll"/></label><span><span>已完成{{doneTotal}}</span> / 全部{{total}}</span><button class="btn btn-danger" @click="clearAll">清除已完成任务</button></div>
</template><script>export default {name:'MyFooter',props:['todos'],computed: {//总数total(){return this.todos.length},//已完成数doneTotal(){//此处使用reduce方法做条件统计/* const x = this.todos.reduce((pre,current)=>{console.log('@',pre,current)return pre + (current.done ? 1 : 0)},0) *///简写return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0) ,0)},//控制全选框isAll:{//全选框是否勾选get(){return this.doneTotal === this.total && this.total > 0},//isAll被修改时set被调用set(value){// this.checkAllTodo(value)this.$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>