标签：after status res for this list const style lis
开始时的判断代码，通过在滚动函数当中再监听一个滚动函数，然后判断前后的差值来判断是向上滚动还是向下滚动
changeIsDownStatus = () => { const listView = this.listView; const beforeScrollTop = listView.scrollTop; this.listView.addEventListener(‘scroll‘, () => { const afterScrollTop = listView.scrollTop; this.isDown = afterScrollTop > beforeScrollTop; }); };
优化后的方法，通过当前的值减去缓存的值，然后再把缓存的值更新为当前的这种方式来判断滚动的方向，这种方式的性能比上面那种更好，同时代码更加的简洁
changeIsDownStatus = () => { const listView = this.listView; this.isDown = listView.scrollTop > this.beforeScrollTop; this.beforeScrollTop = listView.scrollTop; return this.isDown; };
标签：after status res for this list const style lis
原文地址：https://www.cnblogs.com/kugeliu/p/9205299.html
