vue better-scroll 实现滚动

1. npm下载 better-scroll插件
   npm install better-scroll --save
   引入import BScroll from 'better-scroll'

2. 定义data 变量
   data() {
   return {
   goods:[],
   listHeight:[],
   scrollY:0,
   }
   }
   
3. 写样式
   a.获取dom结构的父容器内添加ref="foodwrapper"
   b. :class="{'current':currentIndex == index}"
   c. class="food-list good-List-hook"
   
4. 用this.$refs.menuwrapper获取到dom。
   initScroller() {
   this.menuScroll = new BScroll(this.$refs.menuWrapper, {
   click:true
   });
   this.foodsScroll = new BScroll(this.$refs.foodsWrapper,{
   probeType:3 ,
   click:true
   });
   this.foodsScroll.on('scroll', (pos) => {
   this.scrollY = Math.abs(Math.round(pos.y)) ;
   })
   },
5. 组装高度 listHeight:[],
   calculateHeight(){
   let goodsList =this.$refs.foodsWrapper.getElementsByClassName('good-List-hook');
   let height = 0;
   this.listHeight.push(height);
   for(let i=0;i<goodsList.length;i++){
   let item = goodsList[i];
   height += item.clientHeight;
   this.listHeight.push(height);
   }
   },
   
6. 回调this.initScroller(); this.calculateHeight();事件
   created() {
   this.$nextTick(() =>{
   this.initScroller();
   this.calculateHeight();
   });
   }
   
7. 计算高度listHeight 的当前值currentIndex
   computed:{
   currentIndex(){
   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)){
   return i;
   }
   }
   return 0;
   }
   }
8. 点击事件高亮
   selectMenu(index,event){
   if(!event._constructed){
   return;
   }
   let goodsList = this.$refs.foodsWrapper.getElementsByClassName('good-List-hook');
   let el = goodsList[index];
   this.foodsScroll.scrollToElement(el,300);
   },

7.如果报错可能是要加上
scrollToElement() {
this.scroll && this.scroll.scrollToElement.apply(this.scroll, arguments)
}