vue导航栏刷新，选中样式不修改（选中状态刷新不消失）

for="(item,index) in list" 
     :key="item.value" :to="{path:item.path,query:{item:index}}"
     :class="{'router-link-exact-active':ind == index}"
      @click.native="changeBgc(index)"  class="topbar-item"
    > 
      {{item.label}} 
     

export default {
  data () {
    return {
      list: [
        {path:'/main',label:'处理中心'},
        {path:'/sys',label:'消息中心'},
      ],
      ind: '0'
    }
  },
  methods: {
    changeBgc(index){
      this.ind = index;
    },
  },
  mounted(){
    if(this.$route.query.item){
      this.ind = this.$route.query.item;
    }else{
      this.ind = 0;
    }
  }
}