Vue中使用transform的translateX来实现下滑线跟随导航。

直接看代码。

1、template中的代码

<ul class="tab" :style="{height: tabheight}">
    <li
          ref="iWidth"
          v-for="(item,index) in tabList"
          :key="index"
          :class="{'on': checkindex == index}"
          @click="checkli(index)"
    >{{item}}</li>
    <i :style="{transform:`translateX(${iWidths/2+checkindex*iWidths}px) translateX(-50%)`}"></i>
 </ul>

2、css

ul.tab {
  height: 1000px;
  width: 100%;
  border-bottom: 1px solid #eeeeee;
  line-height: 1rem;
  font-size: 0.32rem;
  color: #333333;
  display: flex;
  position: relative;
  overflow: hidden;
  transition: all 0.5s;
}
.tab li {
  flex: 1;
  text-align: center;
  transition: all 0.5s;
}
.tab li.on {
  color: #da0428;
}
.tab i {
  width: 0.6rem;
  height: 0.05rem;
  border-radius: 0.03rem;
  background: #da0428;
  bottom: 0;
  position: absolute;
  transition: all 0.5s;
}

3、JS代码(实现的主要思路就是通过给元素添加ref属性通过this.$refs.xxx获取此元素的宽度，再配合transform中的translateX属性进行使用。)

<script>
export default {
  name: "orderIndex",
  data() {
    return {
      tabheight: "1rem",
      checkindex: 0,
      tabList: ["全部订单", "待付款", "待收货", "待评价"],
      iWidths: 0
    };
  },

  mounted() {
    var tab = this.$route.query.tab;
    if (tab != undefined && tab != "undefined" && tab != null && tab != "") {
      this.checkindex = tab;
    }
    this.$nextTick(function () {
        this.iWidths = this.$refs.iWidth[0].clientWidth
    })
    
  },
  methods: {
    checkli(index) {
      this.checkindex = index;
    },
  },
  components: {
  }
};
</script>