Implementing waterfall flow layout based on JavaScript (2)

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Implementing waterfall flow layout based on JavaScript (2)_javascript skills

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May 16, 2016 pm 03:18 PM

javascriptWaterfalls flow

The example in this article explains the detailed code of JavaScript implementation of waterfall flow layout, and shares it with everyone for your reference. The specific content is as follows

1. Create Html template

The idea is to first use a div container to hold all the content, then the div box is used to place the picture, and finally the div box_border is used as the picture frame. The code is as follows

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>瀑布流</title>
</head>
<body>
  <div class="container" id="container">
    <div class="box_border" id="box_border">

      <div class="box" id="box1">
        <img  src="/static/imghwm/default1.png"  data-src="image/01.jpg"  class="lazy" alt="Implementing waterfall flow layout based on JavaScript (2)_javascript skills" >
      </div>
  <!--把Box复制多份,这里因为代码重复省略了-->
    </div>
  </div>
</body>
</html>

2. Simply set styles through css

Mainly set horizontal placement, photo frame color, border, etc.

/*
边界不留空,背景黑灰
*/
body{
  margin: 0px;
  background: darkgray;
}
/*
总布局设置为相对布局
*/
.container{
  position: relative;
}
/*
设置box属性
*/
.box{
  padding: 5px;
  float: left;
}
/*设置图片边框阴影和圆角
*/
.box_border{
  padding: 5px;
  border: 1px solid #cccccc;
  box-shadow: 0px 0px 5px #ccc;
  border-radius: 5px;
}
/*设置图片格式*/
.box_border img{
  width: 150px;
  height: auto;
}

3.JS controls the number of pictures placed in each row

After the above CSS layout, the size of the browser window changes, and the number of pictures inside will also change. Now we need to use JS to fix the number of pictures in each row, which can achieve good results for screens of different sizes

/*
 用于加载其他函数
 */
window.onload = function(){
  setImgLocation("container");
}
/*
 设置图片个数
 */
function setImgLocation(parent){
  var cparent = document.getElementById(parent);//得到父节点
  var childArray = getChildNodes(cparent);//得到图片数量
  var imgWidth = childArray[0].offsetWidth;//获取照片宽度
  var screenWidth = document.documentElement.clientWidth;//获取浏览器宽度
  var count = Math.floor(screenWidth/imgWidth);//每行的个数
  cparent.style.cssText = "width:"+count*imgWidth+"px;margin: 0 auto;";//设置其宽度并居中

}


/*
 获取全部图片的个数
 */
function getChildNodes(parent){
  var childArray =[];//定义一个数组存放图片box
  var tempNodes = parent.getElementsByTagName("*");//获取父节点下的所有节点
  //循环添加class为box的节点
  for(var i = 0;i<tempNodes.length;i++){
    if(tempNodes[i].className == "box"){
      childArray.push(tempNodes[i]);
    }
  }
  return childArray;//返回所有的子节点
}
注意:针对不同屏幕大小显示的个数是不一样的

4.JS implements static waterfall flow

First implement a static layout, that is, the browser will not automatically refresh new pictures when pulling down.
Implementing the permutation algorithm is very simple

1. Save all the heights of the first row of images into an array
2. Calculate the minimum height and corresponding position of the image in the first row
3. Place the first picture after the first row at this position
4. Reset the height of the position to the sum of the two images
5. Loop all the remaining pictures in 2

Code:

/*
 用于加载其他函数
 */
window.onload = function(){
  setImgLocation("container");
}
/*
 设置图片个数及位置排列
 */
function setImgLocation(parent){
  var cparent = document.getElementById(parent);//得到父节点
  var childArray = getChildNodes(cparent);//得到图片数量
  var imgWidth = childArray[0].offsetWidth;//获取照片宽度
  var screenWidth = document.documentElement.clientWidth;//获取浏览器宽度
  var count = Math.floor(screenWidth/imgWidth);//每行的个数
  cparent.style.cssText = "width:"+count*imgWidth+"px;margin: 0 auto;";//设置其宽度并居中
  //定义数组,存放第一行照片高度
  var imgHArray = [];
  //循环遍历图片
  for(var i=0;i<childArray.length;i++){
    //如果图片在第一行则获取高度
    if(i<count){
      imgHArray[i] = childArray[i].offsetHeight;
    }else//否则把最小高度的填充剩余图片
    {
      var minHeight = Math.min.apply(null,imgHArray);//获取最小高度
      var minIndex = getMinIndex(minHeight,imgHArray);//获取最小高度对应的下标
      childArray[i].style.position = "absolute";//设置要填充的图片盒子为绝对布局,否则不能更换位置
      childArray[i].style.top = minHeight+"px";//设置要填充图片距顶高度
      childArray[i].style.left = childArray[minIndex].offsetLeft+"px";//设置要填充图片距左高度
      imgHArray[minIndex] += childArray[i].offsetHeight;//填充后把当前位置高度设为两个图片相加
      //开始下一轮循环
    }

  }

}
/*
 获取最小高度对应的下标
 */
function getMinIndex(minHeight,imgHArray){
  for(var i in imgHArray){
    if(imgHArray[i] == minHeight){
      return i;
    }
  }
}
/*
 获取全部图片的个数
 */
function getChildNodes(parent){
  var childArray =[];//定义一个数组存放图片box
  var tempNodes = parent.getElementsByTagName("*");//获取父节点下的所有节点
  //循环添加class为box的节点
  for(var i = 0;i<tempNodes.length;i++){
    if(tempNodes[i].className == "box"){
      childArray.push(tempNodes[i]);
    }
  }
  return childArray;//返回所有的子节点
}

5.js realizes dynamic loading

Dynamic loading means that the scroll bar never slides to the bottom. To solve dynamic loading we need to consider two issues:
1). When to load?
Sliding distance + browser height>Distance between the last picture and the top
2). How to load?
By creating a new node, add the created node to it
Final code:

/*
 用于加载其他函数
 */
window.onload = function() {
  var cparent = document.getElementById("container");//得到父节点
  setImgLocation(cparent);
  //设置加载的图片
  var data = ["image/01.jpg", "image/02.jpg", "image/03.jpg", "image/04.jpg", "image/05.jpg", "image/06.jpg", "image/07.jpg", "image/08.jpg", "image/09.jpg",
    "image/11.jpg", "image/12.jpg", "image/13.jpg", "image/14.jpg", "image/15.jpg", "image/16.jpg", "image/17.jpg"];
  //滑动监听
  window.onscroll = function () {
    if (checkLoad(cparent)) {
      for (var i = 0; i < data.length; i++) {
        //创建新的节点
        var div1 = document.createElement("div");
        div1.className = "box";
        var div2 = document.createElement("div");
        div2.className = "box_border";
        var img = document.createElement("img");
        img.className = ".box_border img";
        img.src = data[i];
        div2.appendChild(img);
        div1.appendChild(div2);
        cparent.appendChild(div1);
      }
      setImgLocation(cparent);//创建节点后重新排列
    }
  }
}


/*
检查是否应该加载
 */
function checkLoad(cparent){
  var childArray = getChildNodes(cparent);//得到图片个数
  var lastImgHight = childArray[childArray.length-1].offsetTop;//得到最后一张图片距离顶部高度
  var scrollHeight = document.documentElement.scrollTop||document.body.scrollTop;//获得滑动距离(浏览器兼容性真烦人)
  var browserHeight = document.documentElement.clientHeight;//获得浏览器高度
  if(lastImgHight < scrollHeight+browserHeight){//判断是否加载
    return true;
  }else {
    return false;
  }
}
/*
 设置图片个数及位置排列
 */
function setImgLocation(cparent){

  var childArray = getChildNodes(cparent);//得到图片数量
  var imgWidth = childArray[0].offsetWidth;//获取照片宽度
  var browserWidth = document.documentElement.clientWidth;//获取浏览器宽度
  var count = Math.floor(browserWidth/imgWidth);//每行的个数
  cparent.style.cssText = "width:"+count*imgWidth+"px;margin: 0 auto;";//设置其宽度并居中
  //定义数组,存放第一行照片高度
  var imgHArray = [];
  //循环遍历图片
  for(var i=0;i<childArray.length;i++){
    //如果图片在第一行则获取高度
    if(i<count){
      imgHArray[i] = childArray[i].offsetHeight;
    }else//否则把最小高度的填充剩余图片
    {
      var minHeight = Math.min.apply(null,imgHArray);//获取最小高度
      var minIndex = getMinIndex(minHeight,imgHArray);//获取最小高度对应的下标
      childArray[i].style.position = "absolute";//设置要填充的图片盒子为绝对布局,否则不能更换位置
      childArray[i].style.top = minHeight+"px";//设置要填充图片距顶高度
      childArray[i].style.left = childArray[minIndex].offsetLeft+"px";//设置要填充图片距左高度
      imgHArray[minIndex] += childArray[i].offsetHeight;//填充后把当前位置高度设为两个图片相加
      //开始下一轮循环
    }

  }

}
/*
 获取最小高度对应的下标
 */
function getMinIndex(minHeight,imgHArray){
  for(var i in imgHArray){
    if(imgHArray[i] == minHeight){
      return i;
    }
  }
}
/*
 获取全部图片的个数
 */
function getChildNodes(parent){
  var childArray =[];//定义一个数组存放图片box
  var tempNodes = parent.getElementsByTagName("*");//获取父节点下的所有节点
  //循环添加class为box的节点
  for(var i = 0;i<tempNodes.length;i++){
    if(tempNodes[i].className == "box"){
      childArray.push(tempNodes[i]);
    }
  }
  return childArray;//返回所有的子节点
}

I hope this article will be helpful to everyone learning JavaScript programming.

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