vue中v-for通过动态绑定class实现触发效果

<template> <div class="app-*">  <ul>   <li    v-for="(item,i) of list"    :key="i"    class="item"    @click="clickIndex=i"    :class="{'click':i==clickIndex}"   ></li>  </ul> </div></template><script>export default { data() {  return {   list: [1, 2, 3, 4],   clickIndex: -1  }; }, methods: {}};</script><style scoped>.item { display: inline-block; width: 100px; height: 100px; cursor: pointer; border: 1px solid black;}.item:hover { background: gray;}.item.click { background: red;}</style>

<template> <div class="hello">   <ul>     <li  v-for="(item, itemIndex) in test"         :key="item.id"         :class="{defaultClass: itemIndex === isActive}"        @mouseenter="onMouseEnter(itemIndex)"         @mouseleave="onMouseLeave">       {{ itemIndex+1 }} :{{ item.title }}       <button v-if="isActive === itemIndex" @click="deleteItem(itemIndex)">删除({{itemIndex+1}})</button>     </li>   </ul> </div></template>

<script>export default { name: 'HelloWorld', data () {  return {   test: [     {          id: 1,       title: 'title first'     },     {       id: 2,       title: 'title second'     },     {       id: 3,       title: 'title third'     }   ],   isActive: ''  } }, methods: {   onMouseEnter(index) {     this.isActive = index   },   onMouseLeave() {     this.isActive = ''   },   deleteItem(index) {     this.test.splice(index, 1)   } }, computed: {    }}</script><!-- Add "scoped" attribute to limit CSS to this component only --><style scoped>h1, h2 { font-weight: normal;}ul { list-style-type: none; padding: 0;}li { /* display: inline-block; */ margin:10px;}a { color: #42b983;}.defaultClass{  background-color: red;}</style>