全局事件总线
使用步骤
1.定义全局事件总线
new Vue({
...
beforeCreated(){
Vue.prototype.$bus=this //安装全局事件总线，$bus就是当前应用的vm
}
...
})2.使用事件总线
a.接收数据：A组件想接收数据，则在A组件中给$bus绑定自定义事件，事件的回调留在A组件自身
export default{
methods(){
demo(data){...}
}
...
mounted(){
this.$bus.$on('xxx',this.demo)
}
}b.提供数据：this.$bus.$emit('xxx',data)
3.最好在beforeDestroy钩子中，用$off()去解绑当前组件所用到的事件
实例
src/main.js
import Vue from 'vue'
import App from './App.vue'
Vue.config.productionTip = false
Vue.prototype.x={a:1,b:2}
//创建vm
new Vue({
el: '#app',
render: h => h(App),
beforeCreate(){
Vue.prototype.$bus=this
}
})src/App.vue
<template>
<div class="app">
<h1>{{ msg }}</h1>
<School/>
<Student/>
</div>
</template>
<script>
import Student from './components/Student'
import School from './components/School'
export default {
name: 'App',
data() {
return {
msg: '你好啊！'
}
},
components: { Student, School }
}
</script>
<style scoped>
.app {
background-color: gray;
padding: 5px;
}
</style>
src/components/Student.vue
<template>
<div class="student">
<h2>学生姓名：{{ name }}</h2>
<h2>学生性别：{{ sex }}</h2>
<button @click="sendStudentName">发送学生名字到学校</button>
</div>
</template>
<script>
export default {
name: 'Student',
data() {
return {
name:'张三',
sex:'男'
}
},
methods:{
sendStudentName(){
this.$bus.$emit('hello',this.name)
}
}
}
</script>
<style lang="less">
.student{
background-color: pink;
padding: 5px;
margin-top: 30px;
}
</style>
src/components/School.vue
<template>
<div class="school">
<h2>学校名称：{{ name}}</h2>
<h2>学校地址：{{ address }}</h2>
</div>
</template>
<script>
export default {
name: 'School',
data() {
return {
name:'黑马',
address:'广州'
}
},
mounted(){
this.$bus.$on('hello',(data)=>{
console.log('我是School组件，收到了数据',data);
})
},
beforeDestroy(){
this.$bus.$off('hello')
}
}
</script>
<style scoped>
.school{
background-color: skyblue;
padding: 5px;
}
</style>
以上是对全局事件总线的运用，接下来是案例使用
(161条消息) Todo-List案例版本三_bubbleJessica的博客-CSDN博客
使用全局事件总线完善
src/main.js
import Vue from 'vue'
import App from './App.vue'
Vue.config.productionTip = false
//创建vm
new Vue({
el: '#app',
render: h => h(App),
beforeCreate(){
Vue.prototype.$bus=this //安装全局事件总线
}
})src/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'
import MyList from './components/MyList'
import MyFooter from './components/MyFooter'
export default {
name: 'App',
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')) || []
}
},
components: { MyHeader, MyList, MyFooter },
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) {
// 注意:filter不改变原数组，只是新建一个数组
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todo
clearAllTodo() {
this.todos = this.todos.filter((todo) => {
return !todo.done
})
}
},
watch: {
// todos简写不包含深度监视
// todos(value) {
// localStorage.setItem('todos', JSON.stringify(value))
// }
// todos完整版深度监视
todos:{
deep:true,
handler(value){
localStorage.setItem('todos', JSON.stringify(value))
}
}
},
mounted(){
this.$bus.$on('checkTodo',this.checkTodo)
this.$bus.$on('deleteTodo',this.deleteTodo)
},
beforeDestroy() {
this.$bus.$off('checkTodo')
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>src/components/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',
props:['todos'],
components: { MyItem }
}
</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>
src/components/MyItem.vue
<template>
<li>
<label>
<input type="checkbox" :checked="todo.done" @change="handleCheck(todo.id)" />
<!-- 以下代码也能实现功能，但是不太推荐，因为有点违反规则，因为修改了props，只不过vue没有监测到（vue监测到的情况是对象全部被变化 -->
<!-- <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: {
handleCheck(id) {
// 通知App组件将对应的todo对象的done值取反
// console.log(id);
// this.checkTodo(id)
this.$bus.$emit('checkTodo',id)
},
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>
