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"
.goods

position absolute
top 3.6rem
bottom .92rem
display flex
width: 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');