vue 类似微信通讯录格式实现网易云音乐的歌手字母查询

<div class="singer wrapper" ref="wrapperSinger">
      <div class="content singerHeight">
        <ul class="singerContent" ref="singerContent">
          <li class="singerContentLi" v-for="item in singerList" :key="item.title" ref="singerItem">    // 这个li循环就是左侧的循环
            <h3 class="singerTitle">{{item.title}}</h3>      //这个是左侧的每个字母
            <ul class="singerTitleUl">
              <li class="singerTitleItem" v-for="items in item.data" :key="items.id">   //这个是左侧字母下的歌手数据
                <img class="iconImg" v-lazy="items.avatar" alt />
                <span class="name">{{items.name}}</span>
              </li>
            </ul>
          </li>
          <li class="singerBetter"></li>
        </ul>
      </div>
</div>

<ul class="singerSort">
        <li
          :class="index == currentIndex ? ‘item current‘ : ‘item‘"
          v-for="(item,index) in listSort"
          :key="index+‘^-^‘"
          @touchstart="onTouchStart"
          @touchmove="onTouchmove"
          @touchend="onTouchEnd"
          :data-index="index"
        >{{item}}</li>
      </ul>

 // 滑动开始
    onTouchStart(e) {
      this.touch = {index:0}  // 首先 touch是一个对象，用来存放 1，点击的index 2，点击的pagey距离 3，滑动的pagey距离
      let index = this.dataIndex(e.target, "data-index");
      this.touch.index = index;
      // 起始的位置
      let y1 = e.touches[0].pageY;
      this.touch.y1 = y1;
      this.currentIndex = index
      this.onClick(index);
    },
    // 获取自定义属性
    dataIndex(el, name) {
      return el.getAttribute(name);
    },
    // 滑动中
    onTouchmove(e) {
      let index = 0
      this.touch.y2 = e.touches[0].pageY
      index =  parseInt((this.touch.y2 - this.touch.y1) / 22) + Number( this.touch.index)   // 这个主要还要考虑到从底部往上拖动
      this.currentIndex = index
      this.onClick(index);
    },
    // 滑动离开
    onTouchEnd() {},
    onClick(index) {
       // 移动中
        this.scroll.scrollToElement(this.$refs.singerItem[index], 0);
    },