vue实现自定义滚动条

具体效果如下，这边我用的rem单位，比例是1:40，

先写下页面布局，把原生的滚动条给隐藏掉，给自定义的滑块增加transition: marginLeft 1s linear;可以使左边距过度的更顺滑

 .top-box-2::-webkit-scrollbar {
    height: 0;
  }

  <div class="wrap">
    <!-- 滚动窗口 -->
    <div
      class="top-box-2"
      @scroll="onScroll"
      ref="box1"
    >
      <div
        class="top-item"
        v-for="(item,index) in 6"
        :key="index"
      ></div>
    </div>
    <!-- 自定义滚动条 -->
    <div
      class="bar"
      ref="bar"
    >
    <!-- 滚动滑块 -->
      <span
        ref="barInner"
        :style="{
        'margin-left':barLeft+'px'
      }"
      ></span>
    </div>
  </div>

首先我们要先获取滚动窗口的滚动百分比

 this.diff = this.$refs.box1.scrollWidth - this.$refs.box1.clientWidth; //获取原生滚动条可以滚动的距离，盒子的总宽度-盒子的可视宽度
      this.barWidth =
        this.$refs.bar.clientWidth - this.$refs.barInner.clientWidth; //获取自定义滚动条可以滚动的距离，盒子的总宽度-滑块的宽度
   

然后获取滚动盒子的百分比，然后设置自定义滚动条滑块的左边距

      this.radio = Math.ceil((e.target.scrollLeft * 100) / this.diff); //获取原生滚动盒子的百分比
      this.barLeft = this.barWidth * (this.radio / 100);   //计算自定义滑块左边距

下面是完整的代码

<template>
  <div class="wrap">
    <!-- 滚动窗口 -->
    <div
      class="top-box-2"
      @scroll="onScroll"
      ref="box1"
    >
      <div
        class="top-item"
        v-for="(item,index) in 6"
        :key="index"
      ></div>
    </div>
    <!-- 自定义滚动条 -->
    <div
      class="bar"
      ref="bar"
    >
      <!-- 滚动滑块 -->
      <span
        ref="barInner"
        :style="{
        'margin-left':barLeft+'px'
      }"
      ></span>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      diff: 0,
      scrollLeft: 0,
      radio: 0,
      barLeft: 0,
      barWidth: 0,
      barInnerWidth: 0,
    };
  },
  mounted() {
    // 延迟2秒执行获取元素宽度的方法，否则原生滚动条可以滚动的距离计算出来会是0
    setTimeout(() => {
      this.$nextTick(() => {
        this.init();
      });
    }, 2000);
  },
  methods: {
    init() {
      this.diff = this.$refs.box1.scrollWidth - this.$refs.box1.clientWidth; //获取原生滚动条可以滚动的距离，盒子的总宽度-盒子的可视宽度
      this.barWidth =
        this.$refs.bar.clientWidth - this.$refs.barInner.clientWidth; //获取自定义滚动条可以滚动的距离，盒子的总宽度-滑块的宽度
    },
    onScroll(e) {
      this.radio = Math.ceil((e.target.scrollLeft * 100) / this.diff); //获取原生滚动盒子的百分比
      this.barLeft = this.barWidth * (this.radio / 100); //计算自定义滑块左边距
    },
  },
};
</script>

<style lang='scss' scoped>
.wrap {
  .top-box-2::-webkit-scrollbar {
    height: 0;
  }
  .top-box-2 {
    display: flex;
    height: 5rem;
    overflow-x: scroll;
    margin: 0 2rem;

    .top-item {
      flex-shrink: 0;
      width: 4rem;
      height: 3rem;
      border: 0.04rem solid red;
      margin: 0.5rem;
      box-sizing: border-box;
      &:first-child {
        margin: 0.5rem 0.5rem 0.5rem 0;
      }
      &:last-child {
        margin: 0.5rem 0 0.5rem 0.5rem;
      }
    }
  }
  .bar {
    width: 3rem;
    border-radius: 0.5rem;
    height: 0.5rem;
    border: 0.02rem solid red;
    margin: 0 auto;
    span {
      display: block;
      width: 0.8rem;
      height: 0.5rem;
      background: blueviolet;
      border-radius: 0.5rem;
      transition: marginLeft 1s linear;
    }
  }
}
</style>