Vue项目中使用better-scroll实现菜单映射功能方法

<template><div class="goods">  <!--左侧区域-->  <div class="menu-wrapper" ref="left">    <ul class="menu">      <li class="menu-item border-bottom"        :class="{'current':currentIndex===index}"        v-for="(item,index) in dataLlist.goods"        :key="index"        @click="selectIndex(index,$event)"        ref="menuList"      >        <div class="text">          <goods-icon v-show="item.type>0" :index="item.type" class="text-ico"></goods-icon>          {{item.name}}        </div>      </li>    </ul>  </div>  <!--右侧区域-->  <div class="foods-wrapper" ref="right">    <ul>      <li class="food-list food-list-hook"        v-for="(item,index) in dataLlist.goods"        :key="index">        <!--标题区域-->        <h1 class="border-left">{{item.name}}</h1>        <ul>          <li class="food-item border-bottom"            v-for="(foodItem,index) in item.foods"          >            <div class="food-image">              <img :src="foodItem.icon" alt="foodItem.name">            </div>            <div class="food-desc">              <div class="title">{{foodItem.name}}</div>              <div class="desc">{{foodItem.description}}</div>              <div class="num">                <div class="sellCount">月售{{foodItem.sellCount}}份</div>                <div class="rating">好评率{{foodItem.rating}}%</div>              </div>              <div class="price">                <div class="new-price">￥{{foodItem.price}}</div>                <div class="old-price border-bottom" v-show="foodItem.oldPrice">￥{{foodItem.oldPrice}}</div>              </div>            </div>          </li>        </ul>      </li>    </ul>  </div></div></template><script>import Icon from '../../common/iconType/Icon';import BScroll from 'better-scroll'export default {  name: "Goods",  props:['dataLlist'],  data(){    return{      listHeight:[],      scrollY:0 ,//为了实现左右区域映射    }  },  computed:{    currentIndex(){ //这个返回的是下标，当这个currentIndex的值与goods的下标一致的时候，      // 左侧区域就会呈现高亮现象      for (let i = 0; i < this.listHeight.length; i++) {        let height1 = this.listHeight[i];        let height2 = this.listHeight[i + 1];        if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {          this._followScroll(i) //实现当滑动的时候，左侧隐藏的食物类型显示          return i;        }      }      return 0;    }  },  created(){    //dataLlist数据是异步加载，直接用new BScroll时，dom可能还没有更新    this.$nextTick(()=>{ //this.$nextTick()将回调延迟到下次 DOM 更新循环之后执行，使用$nextTick异步初始化Bscroll      this.meunScroll=new BScroll(this.$refs.left,{        click:true      });      this.foodScroll=new BScroll(this.$refs.right,{        probeType: 3 //可以派发scroll事件，检测到实时滚动的位置      });      this.foodScroll.on('scroll',(pos) =>{        //参数pos就是在右侧区域滑动的实时位置        //Math.round()取整数,Math.abs取绝对值        this.scrollY =Math.abs( Math.round(pos.y));      });      this._calculateHeight(); //这个方法为了获取每个商品类的最大区间的高度    })  },  methods:{    _followScroll(index) {      if(index > 0 ){        let menuList = this.$refs.menuList;        let el = menuList[index];        this.meunScroll.scrollToElement(el, 300, 0, -100);//better-scroll的scrollToElement方法滚动到指定位置      }      },    _calculateHeight(){ //这个方法为了获取每个商品类的最大区间的高度     let height = 0;     let foodLsit = this.$refs.right.getElementsByClassName('food-list-hook');     this.listHeight.push(height); //listHeight这个数组是用来存放右侧商品中每个类型商品的最大区间高度的集合     for(var i=0;i<foodLsit.length;i++){       let item = foodLsit[i];       //clientHeight代表元素的高度       height += item.clientHeight; //每个元素的高度等于自身高度加上上一个元素的高度       this.listHeight.push(height); //最终listHeight集合了所有li[类为food-list-hook]到最顶部的高度     }    },    selectIndex(index,ele){      //better-scroll 会禁止移动端的点击事件，需要重新派发，同时在PC端会点击两次，此处需要做判断      if(!ele._constructed){        //better-scroll的派发事件scroll的event和pc端浏览器的点击事件的event有个        // 属性区别_constructed，pc端浏览器的点击事件的event中是没有这个属性的        return;      }      let rightItem =this.$refs.right.getElementsByClassName('food-list-hook');      let item = rightItem[index]; //找到相应的li      this.foodScroll.scrollToElement(item, 250) //better-scroll的scrollToElement方法滚动到指定位置    }   // scrollToElement(el, time, offsetX, offsetY, easing) //第一个值接收目标元素，第二个是滚动时间，第三第四个是相对于目标元素的偏移量。},  components:{    'goods-icon': Icon  }}</script><style scoped lang="stylus">@import "../../assets/stylus/mixin.styl".goodsposition absolutetop 3.6rembottom .92remdisplay flexwidth: 100%overflow: hidden.menu-wrapper  flex 0 0 1.6rem  width 1.6rem  background-color #f3f5f7  .menu-item    height 1.08rem    display flex    align-items center    justify-content left    &.border-bottom::before       color rgba(7,17,27,.1)    .text      font-weight 200      font-size .24rem      line-height .28rem      margin 0 .24rem      .text-ico         margin-right -.08rem         vertical-align top;    &.current      font-size .24rem      line-height .28rem      color rgb(240,20,20)      background-color #ffffff.foods-wrapper  flex 1  .food-list    h1      width 100%      height .52rem      line-height .52rem      padding-left .28rem      background-color #f3f5f7      font-size .24rem      color rgb(147,153,159)      &.border-left::before        border-color #d9dde1        border-width .1rem    .food-item      display flex      padding .36rem      &:last-child.border-bottom        border none      .food-desc        margin-left .2rem        font-size .2rem        color rgb(147,153,159)        .title          font-size:.28rem          color rgb(7,17,27)          margin-top .04rem          line-height .28rem        .desc          margin .15rem auto          line-height:.28rem        .num          display flex          margin 0 0 .16rem 0          .sellCount             margin-right .24rem        .price          display flex          align-items center          .new-price            color rgb(220,20,60)            font-weight 700            line-height .48rem            margin-right .16rem            font-size .28rem          .old-price            &.border-bottom::before              position absolute              top: 25%;              border-width: 0.08rem;</style>

npm install better-scroll --save

this.meunScroll=new BScroll(this.$refs.left);this.foodScroll=new BScroll(this.$refs.right);

 this.$nextTick(()=>{ //this.$nextTick()将回调延迟到下次 DOM 更新循环之后执行，使用$nextTick异步初始化Bscroll      this.meunScroll=new BScroll(this.$refs.left,{        click:true //左侧菜单可以进行点击事件      });      this.foodScroll=new BScroll(this.$refs.right,{        probeType: 3 //可以派发scroll事件，检测到实时滚动的位置      });      【this.foodScroll中必须有 probeType: 3后才能进行下面的scroll事件】      this.foodScroll.on('scroll',(pos) =>{        //参数pos就是在右侧区域滑动的实时位置        //Math.round()取整数,Math.abs取绝对值        this.scrollY =Math.abs( Math.round(pos.y));      });      this._calculateHeight(); //这个方法为了获取每个商品类的最大区间的高度    })

     let height = 0;     let foodLsit = this.$refs.right.getElementsByClassName('food-list-hook');     this.listHeight.push(height); //listHeight这个数组是用来存放右侧商品中每个类型商品的最大区间高度的集合     for(var i=0;i<foodLsit.length;i++){       let item = foodLsit[i];       //clientHeight代表元素的高度       height += item.clientHeight; //每个元素的高度等于自身高度加上上一个元素的高度       this.listHeight.push(height); //最终listHeight集合了所有li[类为food-list-hook]到最顶部的高度     }    },let foodLsit = this.$refs.right.getElementsByClassName('food-list-hook');