vue 封装 横向滚动 tab栏 组件

<template>
  <div class="home">
    <header-tab :listArray="list">
      <img :src="imgSrc"  slot="header_tab_img" />
    </header-tab>
  </div>
</template>

<script>
import HeaderTab from "../components/HeaderTab";
export default {
  name: "home",
  components: {
    HeaderTab,
  },
  data() {
    return {
      list: [],
      imgSrc: "",
    };
  },
  created() {
    this.getlist();
    this.imgSrc = require("../assets/img/search.png");
  },
  methods: {
    getlist() {
      this.list = [
        { id: 1, name: "关注" },
        { id: 2, name: "推荐" },
        { id: 3, name: "科技" },
        { id: 4, name: "财经" },
        { id: 5, name: "生活" },
        { id: 6, name: "职场" },
        { id: 7, name: "时尚" },
        { id: 8, name: "汽车" },
        { id: 9, name: "娱乐" },
      ];
    },
  },
};
</script>
<style lang="less"></style>

<template>
  <div class="header">
    <div class="header_tab" ref="headertab">
      <ul ref="tabitem">
        <li
          v-for="(item, index) in listArray"
          :key="index"
          :class="index == current ? ‘activeheader‘ : ‘‘"
          @click="getTab(index, $event)"
        >
          {{ item.name }}
        </li>
      </ul>
    </div>
    <div class="header_search">
      <slot name="header_tab_img"></slot>
    </div>
  </div>
</template>

<script>
export default {
  name: "HeaderTab",
  props: {
    listArray: {
      type: Array,
    },
  },
  data() {
    return {
      current:1,
    };
  },
  methods: {
    getTab(index, e) {
      this.current = index;   // 高亮当前
      let tab =this.$refs.headertab; // 包裹 ul的 div 
      let tabitem = this.$refs.tabitem;    // 包裹 li的 ul
      let winWidth = window.innerWidth;  // 当前屏幕的宽度
      let liList = e.target;   // 当前点击的li
      if (liList) {  //  当前li左偏移, li的宽度, 中间值(当前屏幕的宽度 - li的宽度) /2, 目标值 (中间值 - 当前li左偏移), 整个ul的宽度
        let liLeft = liList.offsetLeft,
          liWidth = liList.offsetWidth,
          liCenter = (winWidth - liWidth) / 2,
          liTarget = liLeft - liCenter;
        let ulWidth = tabitem.offsetWidth;
        if (liTarget < 0) {
          tab.scrollLeft = 0;
          return;
        }
        // winWidth(375) - ulWidth(436) =  -61
        if (liTarget < winWidth - ulWidth) {
          tab.scrollLeft = -(winWidth - ulWidth) + liWidth;
          return;
        }
        tab.scrollLeft = liTarget;
      }
    },
  },
};
</script>
<style lang="less">
.header {
  width: 100%;
  height: 45px;
  background-color: #fff;
  display: flex;
}
.header_tab {
  width: 90%;
  height: 45px;
  display: flex;
  flex-wrap: nowrap;
  overflow: scroll;
}
.header_tab::-webkit-scrollbar {
  display: none;
}
ul {
  display: inline-block;
  white-space: nowrap;
}
li {
  display: inline-block;
  line-height: 45px;
  padding: 0px 10px;
  font-size: 14px;
  color: #333;
  // 点击高亮某一项时,将原来的字体变大,会导致没有高亮的元素距离底部有空隙,会出现纵向滚动条
  margin-top: -1px;
}
.activeheader {
  font-size: 16px;
  font-weight: 700;
  position: relative;
}
.activeheader:after {
  position: absolute;
  content: "";
  width: 35%;
  height: 2px;
  bottom: 0;
  left: 15px;
  background-color: #333;
  border-radius: 50px;
}
.header_search {
  width: 10%;
  height: 45px;
  position: relative;
}

.header_search img {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  margin: auto;
}
</style>