vue 实现设定规定个数列表滚动

<template>
  <div class="hot_news">
    <div class="news_list">
      <ul class="news_list_top">
        <li>新闻类别</li>
        <li>新闻标题</li>
        <li>新闻时间</li>
      </ul>
      <div class="scroll_container">
        <ul class="hot_news_scroll" id="hotNewsScroll">
          <li v-for="(item, index) in hotNews" :key="index">
            <p>【{{item.newsClassesEntity.classes}}】</p>
            <el-tooltip :content="item.title" placement="bottom" effect="light">
              <p>{{item.title}}</p>
            </el-tooltip>
            <p>{{item.publishTime ? item.publishTime.split(" ")[0] : ""}}</p>
            <i class="hot-tip iconfont icon-hot" v-if="[0,1].includes(index)"></i>
          </li>
        </ul>
      </div>
    </div>
  </div>
</template>

<script>
export default {
  props: {
    hotNews: {
      type: Array,
      default: () => {
        return [];
      }
    }
  },
  data() {
    return {
      oList: null,
      scrollTimer: null,
      speed: null,
      scrollNum: null,
      TagName: null,
      distance: null
    };
  },
  mounted() {
    this.initScroll("hotNewsScroll", "li", 1, 2000);
  },
  methods: {
    initScroll(listId, TagName, scrollNum, speed) {
      this.oList = this.$$Dom(listId);
      this.scrollTimer = null;
      this.speed = speed || 1000;
      this.scrollNum = scrollNum || 0;
      this.TagName = TagName;
      this.distance =
        this.oList.getElementsByTagName(TagName)[0].offsetHeight *
        this.scrollNum; //列表移动距离
      this.oList.style.marginTop = 0 + "px";

      this.oList.onmouseover = () => {
        this.pauseScroll();
      };
      this.oList.onmouseout = () => {
        this.scrollTimer = setTimeout(() => {
          this.playScroll();
        }, this.speed);
      };
      this.playScroll();
    },
    playScroll() {
      let options = { marginTop: "-" + this.distance };
      this.animScroll(this.oList, options, () => {
        //回调函数，移动列表元素
        for (let i = 0, j = 0; i < this.scrollNum; i++) {
          var node = this.oList.getElementsByTagName(this.TagName)[j];
          if (this.TagName == "tr") {
            this.oList.getElementsByTagName("tbody")[0].appendChild(node);
          } else {
            this.oList.appendChild(node);
          }
        }
        this.oList.style.marginTop = "0px";
      });

      this.scrollTimer = setTimeout(() => {
        this.playScroll(this.distance);
      }, this.speed);
    },
    pauseScroll() {
      clearTimeout(this.scrollTimer);
    },
    animScroll(oElement, oAttr, fnCallback) {
      var _this = this;
      clearInterval(oElement.timer);
      oElement.timer = setInterval(() => {
        let bStop = true;
        for (let property in oAttr) {
          let iCur = parseFloat(this.cssScroll(oElement, property)); //获取当前位置属性值
          let iSpeed = (oAttr[property] - iCur) / 5; //移动进度
          iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);
          if (iCur != oAttr[property]) {
            //如果当前数值不等于目标数值，则数值递增
            bStop = false;
            this.cssScroll(oElement, property, iCur + iSpeed);
          }
        }
        if (bStop) {
          clearInterval(oElement.timer);
          fnCallback && fnCallback.apply(_this, arguments);
        }
      }, 50);
    },
    cssScroll(oElement, attr, value) {
      if (arguments.length == 2) {
        return oElement.currentStyle
          ? oElement.currentStyle[attr]
          : getComputedStyle(oElement, null)[attr];
      } else if (arguments.length == 3) {
        switch (attr) {
          case "top":
          case "left":
          case "marginTop":
            oElement.style[attr] = value + "px";
            break;
          default:
            oElement.style[attr] = value;
            break;
        }
      }
    },
    $$Dom(o) {
      if (o) {
        return document.getElementById(o);
      }
    }
  }
};
</script>

<style lang="scss">
.hot_news {
  height: 100%;
  .news_list {
    height: 100%;
    box-sizing: border-box;
    padding: 50px 20px 10px;
    .news_list_top {
      height: 26px;
      line-height: 26px;
      font-size: 12px;
      background: rgba(80, 180, 255, 0.05);
      li {
        float: left;
        width: 20%;
        color: #d3f5ff;
        box-sizing: border-box;
        padding: 0 6px;
        &:nth-of-type(2) {
          width: 60%;
        }
      }
    }
    .scroll_container {
      width: 100%;
      max-height: 168px;
      height: 88%;
      overflow: hidden;
      li {
        height: 28px;
        line-height: 28px;
        border-bottom: 1px dashed rgba(67, 237, 248, 0.25);
        cursor: pointer;
        position: relative;
        .hot-tip {
          position: absolute;
          right: 10px;
          top: 50%;
          transform: translateY(-50%);
          color: #c11922;
          font-size: 24px;
        }
        p {
          float: left;
          width: 20%;
          margin: 0;
          height: 100%;
          line-height: 28px;
          font-size: 13px;
          color: #d3f5ff;
          &:nth-of-type(2) {
            width: 60%;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
            box-sizing: border-box;
            padding-right: 20px;
          }
        }
      }
    }
  }
}
</style>