我做的这个瀑布流放在了一个嵌套页面里,就是类似管理后台的main content中,如果要改成全屏的也很方便,其实更容易些,因为会避开一些在元素上使用onScroll的坑。
通过这个瀑布流,可以掌握以下几个知识点:
1、在元素上监听scroll事件,相对直接在window上监听麻烦一点点;
2、image.onload事件;
3、promiseAll;
4、vue 的 transition-group
这里使用了mockjs来模拟图片数据,然后通过axios来调用图片数据,也可使用其他数据源。
通过计算图片高度,判断把图片加载到哪一列。
如果屏幕还有空余,那就继续加载。
无限滚动加载。
屏幕resize这块没有做,后期可以加上去。
直接贴代码,有问题欢迎切磋。
<template> <div ref="waterfall" @scroll="onScroll"> <ul> <transition-group tag="li"> <li v-for="(item,index) in waterfallList" :key="index" :style="{top:item.top+ 'px',left:item.left+'px', width:item.width+'px', height:item.height + 'px'}" > <img :src="item.src" /> </li> </transition-group> </ul> </div> </template> <script> import { getList } from "@/api/demo"; export default { name: "Waterfall", data() { return { waterfallList: [], waterfallCol: 5, colWidth: 236, marginRight: 10, marginBottom: 10, colHeights: [], listQuery: { page: 1, limit: 5, sort: "+id" }, loading: false, show: true }; }, mounted() { this.init(); }, methods: { init() { // 初始化时,每栏高度都为0 this.colHeights = new Array(this.waterfallCol); for (let i = 0; i < this.colHeights.length; i++) { this.colHeights[i] = 0; } this.colWidth = (this.$refs.waterfall.clientWidth - (this.waterfallCol - 1) * this.marginRight) / this.waterfallCol; this.loadImgs(); }, loadImgs() { this.loading = true; // 从api获取数据 getList(this.listQuery).then(res => { let images = res.data.items; let promiseAll = [], imgs = [], total = images.length; for (let i = 0; i < total; i++) { promiseAll[i] = new Promise(resolve => { imgs[i] = new Image(); imgs[i].src = images[i].image_uri; imgs[i].onload = () => { let imgData = {}; imgData.height = (imgs[i].height * this.colWidth) / imgs[i].width; imgData.width = this.colWidth; imgData.src = images[i].image_uri; this.waterfallList.push(imgData); this.rankImgs(imgData); resolve(imgs[i]); }; }); } Promise.all(promiseAll).then(() => { this.loading = false; this.loadMore(); }); }); }, loadMore() { if ( this.$refs.waterfall.clientHeight + this.$refs.waterfall.scrollTop > this.filterMin().minHeight && this.loading == false ) { this.loading = true; setTimeout(() => { this.loadImgs(); }, 200); } }, rankImgs(imgData) { let min = this.filterMin(); imgData.top = min.minHeight; imgData.left = min.minIndex * (this.colWidth + this.marginRight); this.colHeights[min.minIndex] += imgData.height + this.marginBottom; }, filterMin() { let minHeight = Math.min.apply(null, this.colHeights); return { minHeight: minHeight, minIndex: this.colHeights.indexOf(minHeight) }; }, onScroll() { this.loadMore(); } } }; </script> <style lang="scss" scoped> ul li { list-style: none; } .wf-wrap { position: relative; width: 100%; height: 100%; overflow: scroll; } .wf-item { position: absolute; } .wf-item img { width: 100%; height: 100%; } .list-enter-active, .list-leave-active { transition: all 1s; } .list-enter, .list-leave-to /* .list-leave-active for below version 2.1.8 */ { opacity: 0; transform: translateY(30px); } </style>