一、在单vue文件中直接使用
1、html部分
<template>
<div
style="height: 100%;"
v-loading="loading"
>
<ul>
<li v-for="item in data">{{item}} - {{item * 2}}</li>
</ul>
</div>
</template>2、js部分
<script setup>
import {ref} from 'vue'
// loading图片路径
import imgSrc from '@/views/loading.gif'
const data = ref(1)
// 定义loading初始值为true，插入loading
const loading = ref(true)
// 单页面自定义指令直接使用v开头驼峰命名变量，如下
const vLoading = {
// dom加载完，在使用v-loading指令的html节点里添加dom
mounted (el, binding) {
const div = document.createElement('div')
div.className = 'loading'
const img = document.createElement('img')
img.src = imgSrc
img.width = 40
div.appendChild(img)
el.appendChild(div)
},
updated(el, binding) {
// 当值loading绑定的值为false的时候删除dom
if (!binding.value) {
const loadingDom = document.querySelector('.loading')
el.removeChild(loadingDom)
}
}
}
// 模拟异步数据，2秒后loading值为false
setTimeout(() => {
loading.value = false
data.value = 50
}, 2000)
</script>3、实现效果
二、全局注册使用
1、html部分
<template>
<div
style="height: 100%;"
v-loading="loading"
>
<ul>
<li v-for="item in data">{{item}} - {{item * 2}}</li>
</ul>
</div>
</template>2、js部分
在components下创建loading文件夹，在loading文件夹里创建directive.js
// direcitve.js
import imgSrc from "@/views/loading.gif";
const loadingDirective = {
mounted(el, binding) {
const div = document.createElement('div')
div.className = 'loading'
const img = document.createElement('img')
img.src = imgSrc
img.width = 40
div.appendChild(img)
el.appendChild(div)
},
updated(el, binding) {
if (!binding.value) {
const loadingDom = document.querySelector('.loading')
el.removeChild(loadingDom)
}
}
}
export default loadingDirective在main.js中全局注册指令
// 引入loading
import loadingDirective from './components/loading/directive'
let app = createApp(App)
app.use(ElementPlus).use(router)
app.directive('loading', loadingDirective) // 全局注册
app.mount('#app')三、使用vue组件文件实现自定义指令
1、在components下创建loading文件夹，在loading文件夹里创建directive.js
2、在loading文件夹里创建loading.vue
3、在loading文件夹里放入一张GIF图（loading.gif）
1、loading.vue文件源码
// loading.vue
<template>
<div class="loading">
<div class="loading-content">
<img src="./loading.gif" width="24" height="24" alt="">
<p class="desc">{{title}}</p>
</div>
</div>
</template>
<script setup>
// vue3 写法
import { ref, defineExpose } from 'vue'
const title = ref('正在加载...')
const setTitle = (t) => {
title.value = t
}
// 导出setTitle方法
defineExpose({
setTitle
})
// vue2 写法
// export default {
// name: 'loading',
// data() {
// return {
// title: '正在加载...'
// }
// },
// methods: {
// setTitle(title) {
// this.title = title
// }
// }
// }
</script>
<style scoped lang="scss">
.loading {
position: absolute;
top: 50%;
left: 50%;
transform: translate3d(-50%, -50%, 0);
.loading-content {
text-align: center;
.desc {
line-height: 20px;
font-size: $font-size-small;
color: $color-text-l;
}
}
}
</style>
2、js部分（directive.js）
// directive.js
// 引入vue方法createApp
import {createApp} from 'vue'
// 引入添加dom和删除dom的方法
import {addClass, removeClass} from '@/assets/js/dom'
const relativeCls = 'g-relative'
const loadingDirective = {
mounted (el, binding) {
// 创建一个loading的vue实例
const app = createApp(Loading)
// 挂载loading.vue 到div DOM上
const instance = app.mount(document.createElement('div'))
// 把instance挂到要用指令的element下
el.instance = instance
const title = binding.arg
// 如果传了title就重新设置title的值
if (typeof title !== 'undefined') {
instance.setTitle(title)
}
// 指令绑定的值为true把自定义的vue实例下的dom节点$el添加到el下
if (binding.value) {
append(el)
}
},
// 指令绑定的值更新以后
updated (el, binding) {
const title = binding.arg
if (typeof title !== 'undefined') {
el.instance.setTitle(title)
}
if (binding.value !== binding.oldValue) {
// 指令绑定的值为true添加指令dom，否则删除指令的dom
binding.value ? append(el) : remove(el)
}
}
}
function append(el) {
const style = getComputedStyle(el)
// 如果要绑定的dom没有定位就添加一个有定位的classi
if (!['absolute', 'fixed', 'relative'].includes(style.position)) {
addClass(el, relativeCls)
}
el.appendChild(el.instance.$el)
}
function remove(el) {
removeClass(el, relativeCls)
el.removeChild(el.instance.$el)
}
export default loadingDirective3、@/assets/js/dom.js源码
export function addClass(el, className) {
if (!el.classList.contains(className)) {
el.classList.add(className)
}
}
export function removeClass(el, className) {
el.classList.remove(className)
}
4、main.js源码
// 引入loading
import loadingDirective from './components/loading/directive'
let app = createApp(App)
app.use(ElementPlus).use(router)
app.directive('loading', loadingDirective) // 全局注册
app.mount('#app')四、进阶（有多个自定义指令）
1、封装一个通用的js
把自定义组件的方法拎出来单独弄一个js文件，我习惯放在src/assets/js/create-my-like-directive.js
// create-my-like-directive.js
import { createApp } from 'vue'
import { addClass, removeClass } from '@/assets/js/dom'
const relativeCls = 'g-relative'
export default function createMyLikeDirective (Comp) { // 改动的地方，变成可传参的方法
return {
mounted (el, binding) {
const app = createApp(Comp) // 传入变动参数
const instance = app.mount(document.createElement('div'))
const name = Comp.name
if (!el[name]) {
el[name] = {}
}
// 把实例挂载到dom的name下，防止多个自定义指令互相影响干扰出现bug
el[name].instance = instance
const title = binding.arg
if (title) {
instance.setTitle(title)
}
if (binding.value) {
append(el)
}
},
updated (el, binding) {
const title = binding.arg
const name = Comp.name
if (title) {
el[name].instance.setTitle(title)
}
if (binding.value !== binding.oldValue) {
binding.value ? append(el) : remove(el)
}
}
}
function append (el) {
const style = getComputedStyle(el)
const name = Comp.name
if (!['absolute', 'fixed', 'relative'].includes(style.position)) {
addClass(el, relativeCls)
}
el.appendChild(el[name].instance.$el)
}
function remove (el) {
const name = Comp.name
removeClass(el, relativeCls)
el.removeChild(el[name].instance.$el)
}
}
2、directive.js修改
import Loading from './loading.vue'
import createMyLikeDirective from '@/assets/js/create-my-like-directive'
// 如果有不同的自定义好的vue文件，Loading变为别的vue文件即可
const loadingDirective = createMyLikeDirective(Loading)
export default loadingDirective3、main.js修改
// 引入loading
import loadingDirective from './components/loading/directive'
// 引入其他的
import AAAA from './components/AAAA/directive'
import BBBB from './components/BBBB/directive'
let app = createApp(App)
app.use(ElementPlus).use(router)
app.directive('loading', loadingDirective) // 全局注册
app.directive('aaaa', AAAA) // 全局注册
app.directive('bbbb', BBBB) // 全局注册
app.mount('#app')
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