css佈局-瀑布流的實現

1、基本思路javascript

一、先看最終的效果圖:css

二、實現原理:經過position:absolute(絕對定位)來定位每個元素的位置,而且將當前列的高度記錄下來方便下一個dom位置的計算html

2、代碼實現java

一、版本一:根據思路實現基礎版數組

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>css佈局-瀑布流的實現</title>
<style type="text/css">
.box {
  position: relative;
	width: 500px;
	min-height: 100px;
	margin: 100px auto;
	background: #eeeeee;
}
.item {
  position: absolute;
  width: 120px;
  left: 0;
  top: 0;
}
</style>
</head>
<body>
<div class="box">
    <div class="item" style="height: 40px;background: red;"></div>
    <div class="item" style="height: 50px;background: blue;"></div>
    <div class="item" style="height: 100px;background: green;"></div>
    <div class="item" style="height: 60px;background: gray;"></div>
    <div class="item" style="height: 50px;background: orange;"></div>
    <div class="item" style="height: 20px;background: yellow;"></div>
    <div class="item" style="height: 40px;background: red;"></div>
    <div class="item" style="height: 50px;background: blue;"></div>
    <div class="item" style="height: 100px;background: green;"></div>
    <div class="item" style="height: 120px;background: gray;"></div>
    <div class="item" style="height: 58px;background: orange;"></div>
    <div class="item" style="height: 36px;background: yellow;"></div>
</div>
<script type="text/javascript">
  const BOX_WIDTH = document.querySelector('.box').offsetWidth //瀑布流外層盒子的寬度
  const ITEM_WIDTH = document.querySelector('.item').offsetWidth //瀑布流內層盒子的寬度
  const COLUMN = Math.floor(BOX_WIDTH/ITEM_WIDTH)   //根據寬度計算可渲染的列數
  const MARGIN = (BOX_WIDTH - ITEM_WIDTH*COLUMN)/(COLUMN-1) // 根據寬度計算每一列的間距
  const MARGINTOP = 10 //固定設置每個小盒子上下間距是10
  let height_arr = new Array(COLUMN).fill(0)  //定義一個長度等同與列數的數組用來存儲每一列的高度,初始值均爲0
  let item = document.querySelectorAll('.item')
//遍歷每個小盒子,肯定小盒子的位置 for(let i = 0; i < item.length; i++) { let index = height_arr.indexOf(Math.min.apply(null, height_arr)) item[i].style.left = (ITEM_WIDTH + MARGIN) * index + 'px' item[i].style.top = height_arr[index] + MARGINTOP + 'px' height_arr[index] += item[i].offsetHeight + MARGINTOP }
//將數組中最大的值,即最高的那一列的高度賦給外層盒子 document.querySelector('.box').style.height = Math.max.apply(null, height_arr) + 'px' </script> </body> </html>

二、版本二:對版本一進行封裝,方便重複使用app

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>css佈局-瀑布流的實現</title>
<style type="text/css">
.box {
  position: relative;
	width: 500px;
	min-height: 100px;
	margin: 100px auto;
	background: #eeeeee;
}
.item {
  position: absolute;
  width: 120px;
  left: 0;
  top: 0;
}
</style>
</head>
<body>
<div class="box" style="">
    <div class="item" style="height: 40px;background: red;"></div>
    <div class="item" style="height: 50px;background: blue;"></div>
    <div class="item" style="height: 100px;background: green;"></div>
    <div class="item" style="height: 60px;background: gray;"></div>
    <div class="item" style="height: 50px;background: orange;"></div>
    <div class="item" style="height: 20px;background: yellow;"></div>
   <div class="item" style="height: 40px;background: red;"></div>
   <div class="item" style="height: 50px;background: blue;"></div>
   <div class="item" style="height: 100px;background: green;"></div>
   <div class="item" style="height: 120px;background: gray;"></div>
   <div class="item" style="height: 58px;background: orange;"></div>
   <div class="item" style="height: 36px;background: yellow;"></div>
</div>
<script type="text/javascript">
	function WaterFall(params) {
		this.box = (params && params.parent) || '.box'
		this.item = (params && params.child) || '.item'
		this.column = (params && params.column) || 0
		this.row_margin = (params && params.row_margin) || 0
		this.column_margin = (params && params.column_margin) || 10
		this.height_arr = []
		this._box_width = 0
		this._item_width = 0
		this._computed = function() {
			this._box_width = document.querySelector(this.box).offsetWidth
			this._item_width = document.querySelector(this.item).offsetWidth
			this.column = Math.floor((this._box_width - this.row_margin)/this._item_width) //列數
			this.row_margin = !this.row_margin ? (this._box_width - this._item_width * this.column)/(this.column-1) : this.row_margin
		}
		this.init = function() {
			this._computed()
			let item = document.querySelectorAll(this.item)
			this.height_arr = new Array(this.column).fill(0)
			for(let i = 0; i < item.length; i++) {
				let index = this.height_arr.indexOf(Math.min.apply(null, this.height_arr))
				item[i].style.left = (this._item_width + this.row_margin) * index + 'px'
				item[i].style.top = this.height_arr[index] + this.column_margin + 'px'
				this.height_arr[index] += item[i].offsetHeight + this.column_margin
			}
			document.querySelector('.box').style.height = Math.max.apply(null, this.height_arr) + 'px'
		}
	}
	var test = new WaterFall()
	test.init()
</script>
</body>
</html>

 

3、總結:瀑布流的實現並不複雜,只要清楚了原理剩下的就是耐心的計算間距以及小盒子的位置啦~dom

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