web页面和小程序页面实现瀑布流效果

时间：2023-03-09 04:17:08
web页面和小程序页面实现瀑布流效果

　　小程序实现瀑布流效果，和web页面差不多，都要经过以下步骤：

1)、加载图片，获取图片的宽高度；

2)、根据页面需要显示几列计算每列的宽度；

3)、根据图片真实宽度和每列的宽度比，计算出图片需要显示的高度；

4)、重新对图片进行定位

　　1、web页面瀑布流效果，先看效果图（瀑布流+无限滚动加载）：

web页面和小程序页面实现瀑布流效果

　页面代码：

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

        <meta charset=’utf-8′> <!--声明文档使用的字符编码-->

        <title>瀑布流_左浮动</title>

    <style type="text/css">

        *{margin:0;padding:0;}

        .container {

            width: 1200px; height: auto; margin: 50px auto;

            position: relative;

        }

        .box{

            padding: 5px; box-shadow: 0 0 10px purple; border-radius: 5px;

            float: left; margin: 10px;

        }

        .box img { width: 200px; height: auto; }

    </style>

</head>

<body>

    <div class="container">

        <div class="box"><img src="../img/0.jpg"/></div>

        <div class="box"><img src="../img/1.jpg"/></div>

        <div class="box"><img src="../img/2.jpg"/></div>

        <div class="box"><img src="../img/3.jpg"/></div>

        <div class="box"><img src="../img/4.jpg"/></div>

        <div class="box"><img src="../img/5.jpg"/></div>

        <div class="box"><img src="../img/6.jpg"/></div>

        <div class="box"><img src="../img/7.jpg"/></div>

        <div class="box"><img src="../img/8.jpg"/></div>

        <div class="box"><img src="../img/9.jpg"/></div>

        <div class="box"><img src="../img/10.jpg"/></div>

        <div class="box"><img src="../img/11.jpg"/></div>

        <div class="box"><img src="../img/12.jpg"/></div>

        <div class="box"><img src="../img/13.jpg"/></div>

        <div class="box"><img src="../img/14.jpg"/></div>

        <div class="box"><img src="../img/15.jpg"/></div>

        <div class="box"><img src="../img/16.jpg"/></div>

    </div>

    <script type="text/javascript">

        var boxsHeight = []; //盒子高度存储数组

        var boxWidth = 230, boxHeight = 230;

        window.onload = function(){

            var boxs = document.getElementsByClassName('box');

            var cols = Math.floor(1200.0/boxWidth); //最多几列

            //offsetWidth: 包括元素的内容宽度+padding+border宽度

            //存储第一行的每个盒子的高度到数组里面

            for (var i = 0; i < cols; i++){

                var obj = boxs[i]; //元素节点

                if (i < cols){

                    boxsHeight.push(obj.offsetHeight);

                }

            }

            updateBoxFrame(cols);  //从第二行开始更新元素的位置

            window.onscroll = pageScroll;  //设置页面滚动监听函数

            pageScroll();  //先调用一次

        }

        //获取数组中最小值的索引

        function getMinHeightIndex(arr){

            var minHeight = Math.min.apply(null, arr);

            for (var i = 0; i < arr.length; i++){

                if (arr[i] == minHeight){

                    return i;

                }

            }

        }

        //监听页面滚动

        function pageScroll(){

            var parentEle = document.getElementsByClassName('container')[0];

            var subEleCount = parentEle.childElementCount; //子元素个数

            var lastBox = parentEle.lastElementChild; //最后一个元素

            //判断是否滚动到底部

            var doc = document.documentElement||document.body;

            console.log('滚动监听', doc.scrollTop+",", lastBox.offsetTop+", " + doc.clientHeight);

            if (doc.scrollTop+doc.clientHeight > lastBox.offsetTop){

                //表示该新添加元素了

                addBox();

                //更新新添加元素的位置

                updateBoxFrame(subEleCount);

            }

        }

        //新添加子元素

        function addBox(){

            var parentEle = document.getElementsByClassName('container')[0];

            var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];

            for (var i = 0; i < arr.length; i++){

                var index = parseInt(Math.random()*100%arr.length);

                var imgNum = arr[index];

                var div = document.createElement('div');

                div.setAttribute('class', 'box');

                div.innerHTML = '<img src="../img/' + imgNum + '.jpg"/>'

                parentEle.appendChild(div);

                arr.splice(index, 1)

            }

        }

        //更新新添加元素的位置

        function updateBoxFrame(startIndex){

            var boxs = document.getElementsByClassName('box');

            for (var i = startIndex; i < boxs.length; i++){

                var obj = boxs[i];

                //获取数组中最小高度的索引

                var minHeightIndex = getMinHeightIndex(boxsHeight);

//                    console.log(boxsHeight);

//                    console.log(minHeightIndex + ", " +boxsHeight[minHeightIndex]);

                var boxTop = boxsHeight[minHeightIndex] + 20;

                var boxLeft = minHeightIndex * boxWidth;

                console.log(i + ', boxTop: ' + boxTop + ", boxLeft: " + boxLeft);

                //设置元素的定位样式

                obj.style = 'position: absolute; top:' + boxTop + "px;left:" + boxLeft+"px";

                boxsHeight[minHeightIndex] = boxTop + obj.offsetHeight;

            }

        }

    </script>

</body>

</html>

　　2、小程序实现瀑布流，大致流程差不多。只不过小程序的图片的宽高度的获取没有web页面那么方便。

大概实现过程：1）、获取图片数据，页面渲染；

　　　　　　2）、给图片绑定加载load事件，存储每个图片的宽高度；

　　　　　　3）、计算每个图片的定位，重新渲染

　　

先看小程序的效果图（瀑布流+无限循环加载）：

web页面和小程序页面实现瀑布流效果

wxml页面代码：

<scroll-view class='main' scroll-y='true' style="height:{{windowHeight}}px" bindscrolltolower='loadMoreImages'>

    <image wx:for='{{dataList}}' wx:key='item' src='{{item.src}}' style='position: absolute; top: {{item.top}}px; left: {{item.left}}px; width: {{imgWidth}}px; height: {{item.height}}px' bindload='loadImage' data-index='{{index}}' bindtap='previewImg'/>

</scroll-view>

js页面代码：

// pages/discover/waterfall_flow/waterfall_flow.js

Page({

  /**

   * 页面的初始数据

   */

  data: {

    dataList: [], //数据源

    windowWidth: 0, //页面视图宽度

    windowHeight: 0, //视图高度

    imgMargin: 6, //图片边距: 单位px

    imgWidth: 0,  //图片宽度: 单位px

    topArr: [0, 0], //存储每列的累积top

  },

  /**

   * 生命周期函数--监听页面加载

   */

  onLoad: function (options) {

    wx.showLoading({

      title: '加载中...',

    })

    var that = this;

    //获取页面宽高度

    wx.getSystemInfo({

      success: function (res) {

        console.log(res)

        var windowWidth = res.windowWidth;

        var imgMargin = that.data.imgMargin;

        //两列，每列的图片宽度

        var imgWidth = (windowWidth - imgMargin * 3) / 2;

        that.setData({

          windowWidth: windowWidth,

          windowHeight: res.windowHeight,

          imgWidth: imgWidth

        }, function () {

          that.loadMoreImages(); //初始化数据

        });

      },

    })

  },

  //加载图片

  loadImage: function (e) {

    var index = e.currentTarget.dataset.index; //图片所在索引

    var imgW = e.detail.width, imgH = e.detail.height; //图片实际宽度和高度

    var imgWidth = this.data.imgWidth; //图片宽度

    var imgScaleH = imgWidth / imgW * imgH; //计算图片应该显示的高度

    var dataList = this.data.dataList;

    var margin = this.data.imgMargin;  //图片间距

    //第一列的累积top，和第二列的累积top

    var firtColH = this.data.topArr[0], secondColH = this.data.topArr[1];

    var obj = dataList[index];

    obj.height = imgScaleH;

    if (firtColH < secondColH) { //表示新图片应该放到第一列

      obj.left = margin;

      obj.top = firtColH + margin;

      firtColH += margin + obj.height;

    }

    else { //放到第二列

      obj.left = margin * 2 + imgWidth;

      obj.top = secondColH + margin;

      secondColH += margin + obj.height;

    }

    this.setData({

      dataList: dataList,

      topArr: [firtColH, secondColH],

    });

  },

  //加载更多图片

  loadMoreImages: function () {

    var imgs = [

      'https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=1409185525,4059560780&fm=26&gp=0.jpg',

      'https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=4076355782,2436939971&fm=15&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=777075993,2126273204&fm=11&gp=0.jpg',

      'https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=57777155,3251523579&fm=11&gp=0.jpg',

      'https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=3825727093,2830650732&fm=11&gp=0.jpg',

      'https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=2379065095,654347953&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=2749679283,2472217536&fm=11&gp=0.jpg',

      'https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=677128138,409184861&fm=11&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFvHSh_Q1YnxGkpoWK1HF6hhy/it/u=1884091074,3049103326&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=1600363417,3661952978&fm=11&gp=0.jpg',

      'https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=2069544162,3090555174&fm=11&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=3328655038,3143543956&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=3953624046,2332872335&fm=26&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=717009955,687560133&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=4243037288,2388509769&fm=26&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2644451528,4180971732&fm=26&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2658655215,924706045&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=400545645,1325440240&fm=26&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFvHSh_Q1YnxGkpoWK1HF6hhy/it/u=2735743532,3162562682&fm=11&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=2357555025,1781222560&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=1604156508,3282489713&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=380663325,2271064034&fm=26&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFvHSh_Q1YnxGkpoWK1HF6hhy/it/u=174537541,3462862985&fm=26&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=1752649241,364583051&fm=26&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=2890516059,4166188770&fm=27&gp=0.jpg',

      'https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=2435144503,200941795&fm=11&gp=0.jpg',

      'https://ss0.bdstatic.com/70cFvHSh_Q1YnxGkpoWK1HF6hhy/it/u=877833827,2847590581&fm=26&gp=0.jpg',

      'https://ss3.bdstatic.com/70cFv8Sh_Q1YnxGkpoWK1HF6hhy/it/u=894452177,2810600152&fm=11&gp=0.jpg',

      'https://ss2.bdstatic.com/70cFvnSh_Q1YnxGkpoWK1HF6hhy/it/u=4053642431,248486335&fm=27&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=2914607659,905736210&fm=11&gp=0.jpg',

      'https://ss1.bdstatic.com/70cFvXSh_Q1YnxGkpoWK1HF6hhy/it/u=1629456501,1514429218&fm=26&gp=0.jpg',

    ];

    var tmpArr = [];

    for (let i = 0; i < 22; i++) {

      var index = parseInt(Math.random() * 100) % imgs.length;

      var obj = {

        src: imgs[index],

        height: 0,

        top: 0,

        left: 0,

      }

      tmpArr.push(obj);

      imgs.splice(index, 1);

    }

    var dataList = this.data.dataList.concat(tmpArr)

    this.setData({ dataList: dataList }, function(){

      wx.hideLoading()

    });

  },

  /**预览图片 */

  previewImg: function (e) {

    var index = e.currentTarget.dataset.index;

    var dataList = this.data.dataList;

    var currentSrc = dataList[index].src;

    // var srcArr = dataList.map(function (item) {

    //   return item.src;

    // });

    wx.previewImage({

      urls: [currentSrc],

    })

  },

})

wxss页面代码：

.main{ width: 100%; height: 100%; position: relative; }

.main image {

  box-shadow: 0 0 10rpx red; border-radius: 8rpx;

}

DEMO下载：https://github.com/xiaotanit/Tan_HtmlDemo

web瀑布流页面地址：https://github.com/xiaotanit/Tan_HtmlDemo/blob/master/JS/%E7%80%91%E5%B8%83%E6%B5%81_%E5%B7%A6%E6%B5%AE%E5%8A%A8.html

小程序瀑布流页面地址：https://github.com/xiaotanit/Tan_HtmlDemo/tree/master/wxMini/pages/discover/waterfall_flow

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