vue实现底部菜单功能

<template>  <div class="mui-row">    <div class="mui-col-xs-12 mui-row nav">      <div class="mui-col-xs-4" @tap="tab1=1;tab2=1;tab3=1">        <router-link to="/recommend" ><img :src="'img/tabIcon/tab1'+tab1+'.png'" @tap="tab1=1;tab2=1;tab3=1"/><span class="mui-tab-label" @tap="tab1=1;tab2=1;tab3=1">{{"推荐好课" | title}}</span></router-link>      </div>      <div class="mui-col-xs-4" @tap="tab2=2;tab1=2;tab3=1">        <router-link :to="{path: '/Broadcast/' +(tabNum=tabNum==undefined?0:tabNum)}"><img :src="'img/tabIcon/tab2'+tab2+'.png'" @tap="tab2=2;tab1=2;tab3=1"/><span class="mui-tab-label" @tap="tab2=2;tab1=2;tab3=1">{{"师道直播" | title}}</span></router-link>      </div>      <div class="mui-col-xs-4" @tap="tab3=2;tab1=2;tab2=1">        <router-link to="/my"><img :src="'img/tabIcon/tab3'+tab3+'.png'" @tap="tab3=2;tab1=2;tab2=1"/><span class="mui-tab-label" @tap="tab3=2;tab1=2;tab2=1">{{"我" | title}}</span></router-link>      </div>    </div>  </div> </template><style scoped>  .mui-row { background: #FFF; border-top:1px solid #F5F5F5; }  .mui-col-xs-12 .mui-col-xs-4 { text-align: center; height: 50px; }  img{position:relative; top:0px; width: 30px; height: 30px; padding-top: 0; padding-bottom: 0; }  .mui-tab-label{ font-size: 11px; display: block; overflow: hidden; text-overflow: ellipsis; margin-top: -7px; }  a{color:#b9b5b5;}  .mui-bar{ -webkit-box-shadow: 0 0 1px rgba(222, 219, 219, 0.85); box-shadow: 0 0 1px rgba(222, 219, 219, 0.85); }  .mui-row .router-link-exact-active.router-link-active{ color:#3FCDFF; }   .mui-col-xs-12 .mui-col-xs-4 a{height: 50px; display: inline-block; width: 100%;}</style><script> export default {    created() {     this.$route.params.tabNum=0;    },    mounted() {    if(this.$route.params.tabNum!='undefined'){     this.tabNum=this.$route.params.tabNum;//因为这个切换选项卡就path改变了      }     else{     this.tabNum=0;      }      if(this.$route.path=='/my'){     this.tab3=2;this.tab1=2;this.tab2=1     }     else if(this.$route.path=='/Broadcast/'+this.tabNum){//因为这里的path是随着选项卡切换改变的。所以要写成动态的。     this.tab2=2;this.tab1=2;this.tab3=1     }else{     this.tab1=1;this.tab2=1;this.tab3=1     }        },    beforeRouteEnter(to, from, next) {    // console.log(to)    //   if (to.params.db == null) {    //     return next({ name: "", params: { id: to.params.id } });    //   }    //   next();      },    components: {},    data() {      return {        tabNum:0,        tab1:1,        tab2:1,        tab3:1,      }    },    methods: {    },    watch:{     "$route.params"(tab){ //     this.tabNum=this.$route.params.tabNum;      },     }  }</script>