彈性盒子基礎
彈性盒子(Flexible Box)是css3中盒子模型的彈性布局,在傳統的布局方式上增加了很多靈活性。
定義一個彈性盒子
在父盒子上定義display屬性:
#box{
display: -webkit-flex; //webkit內核瀏覽器的兼容設置,下同
display: flex;
}
當然還有行內布局的彈性盒子
#box{
display: -webkit-inline-flex;
display: inline-flex;
}
注意,設為Flex布局以后,子元素的float、clear和vertical-align屬性將失效。
彈性盒子兼容情況
- Chrome 29+
- Firefox 28+
- Internet Explorer 11+
- Opera 17+
- Safari 6.1+ (prefixed with -webkit-)
- Android 4.4+
- iOS 7.1+ (prefixed with -webkit-)
彈性盒子概念
彈性盒子兩個軸如圖:
- 主軸(橫軸, main axis)
- 交叉軸(縱軸, cross axis)
彈性盒子屬性
在研究具體屬性前,先建立一個基本模板,必要時修改一下部分參數:
<!-- html部分 -->
<div id="flex-box">
<div class="flex-item">1</div>
<div class="flex-item">2</div>
<div class="flex-item">3</div>
<div class="flex-item">4</div>
<div class="flex-item">5</div>
</div>
<!-- css部分 -->
#flex-box{
width: 200px;
height: 200px;
border: 1px solid #06f;
display: flex;
display: -webkit-flex;
}
.flex-item{
height: 30px;
width: 30px;
color: #f00;
font-size: 20px;
line-height: 30px;
text-align: center;
background-color: #8f0;
border: 1px solid #f00;
}
- flex-direction
排列方向設置
#flex-box{
flex-direction: row | row-reverse | column | column-reverse;
/* @value row 從左到右(默認)*/
/* @value row-reverse 從右到左*/
/* @value column 從上到下*/
/* @value column-reverse 從下到上*/
}
- flex-wrap
換行設置
.box{
flex-wrap: nowrap | wrap | wrap-reverse;
/* @value nowrap 不換行(默認)*/
/* @value wrap 換行*/
/* @value wrap-reverse 換行 層倒序*/
}
- flex-flow
flex-direction和flex-wrap的縮寫屬性
.box {
flex-flow: <flex-direction> || <flex-wrap>;
}
- justify-content
水平方向上對齊
.box {
justify-content: flex-start | flex-end | center | space-between | space-around;
}
/* value flex-start 左對齊(默認)*/
/* value flex-end:右對齊*/
/* value center: 居中*/
/* value space-between:兩端對齊,項目之間的間隔都相等*/
/* value space-around:每個項目兩側的間隔相等。所以,項目之間的間隔比項目與邊框的間隔大一倍*/
- align-items
垂直方向上對齊
.box {
align-items: flex-start | flex-end | center | baseline | stretch;
}
/* value flex-start 交叉軸的起點對齊*/
/* value flex-end 交叉軸的終點對齊*/
/* value center 交叉軸的中點對齊*/
/* value baseline 項目的第一行文字的基線對齊*/
/* value stretch 如果項目未設置高度或設為auto,將占滿整個容器的高度(默認)*/
- align-content
多根軸線的對齊方式
.box {
align-content: flex-start | flex-end | center | space-between | space-around | stretch;
}
/* value flex-start 與交叉軸的起點對齊*/
/* value flex-end 與交叉軸的終點對齊*/
/* value center 與交叉軸的中點對齊*/
/* value space-between 與交叉軸兩端對齊,軸線之間的間隔平均分布*/
/* value space-around 每根軸線兩側的間隔都相等。所以,軸線之間的間隔比軸線與邊框的間隔大一倍*/
/* value stretch 軸線占滿整個交叉軸(默認值)*/
子元素屬性
- order: 屬性定義項目的排列順序。數值越小,排列越靠前,默認為0
- flex-grow: 屬性定義項目的放大比例,默認為0,即如果存在剩余空間,也不放大
- flex-shrink: 屬性定義了項目的縮小比例,默認為1,即如果空間不足,該項目將縮小。
- flex-basis: 屬性定義了在分配多余空間之前,項目占據的主軸空間它的默認值為auto,即項目的本來大小。
- flex: 屬性是flex-grow, flex-shrink和flex-basis的簡寫。
- align-self: 屬性允許單個項目有與其他項目不一樣的對齊方式,可覆蓋align-items屬性。默認值為auto,表示繼承父元素的align-items屬性,如果沒有父元素,則等同於stretch。
多列
- column-count 規定元素應該被分隔的列數
- column-fill 規定如何填充列
- column-gap 規定列之間的間隔
- column-rule 設置所有column-rule-*屬性的簡寫屬性
- column-rule-color 規定列之間規則的顏色
- column-rule-style 規定列之間規則的樣式
- column-rule-width 規定列之間規則的寬度
- column-span 規定元素應該橫跨的列數
- column-width 規定列的寬度
- columns 規定設置column-width和column-count的簡寫屬性
實例
骰子
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>9 faces Dice</title>
</head>
<style>
body{
padding: 0;
margin: 0;
}
#demo{
display: flex;
background-color: #444;
}
.dice{
width: 90px;
height: 90px;
border-radius: 22px;
margin: 20px;
padding: 10px;
box-sizing: border-box;
border: 2px solid #aaa;
background-color: #eee;
display: flex;
flex-direction: column;
justify-content: space-between;
}
.dot{
width: 20px;
height: 20px;
background-color: #222;
border-top: 2px solid #000;
box-sizing: border-box;
/*box-shadow: 0px 0px 2px #000;*/
border-radius: 20px;
}
.line{
display: flex;
justify-content: space-between;
}
#one{
justify-content: center;
align-items: center;
}
#two{
align-items: center;
}
#three .line:nth-of-type(2){
justify-content: center;
}
#three .line:nth-of-type(3){
justify-content: flex-end;
}
#five .line:nth-of-type(2){
justify-content: center;
}
</style>
<body>
<div id="demo">
<div id="one" class="dice">
<div class="line">
<div class="dot"></div>
</div>
</div>
<div id="two" class="dice">
<div class="line">
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
</div>
</div>
<div id="three" class="dice">
<div class="line">
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
</div>
</div>
<div id="four" class="dice">
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
</div>
<div id="five" class="dice">
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
</div>
<div id="six" class="dice">
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
</div>
<div id="seven" class="dice">
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
</div>
<div id="eight" class="dice">
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
<div class="dot"></div>
</div>
</div>
<div id="nine" class="dice">
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
<div class="dot"></div>
</div>
<div class="line">
<div class="dot"></div>
<div class="dot"></div>
<div class="dot"></div>
</div>
</div>
</div>
</body>
</html>
瀑布流圖
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<title>test</title>
<style>
ul{
width: 1000px;
margin: 0 auto;
padding: 0;
columns: 4;
list-style: none;
column-gap: 2px;
column-fill: balance;
}
ul li {
margin: 4px 0;
}
ul li img{
width:240px;
}
</style>
</head>
<body>
<ul>
<li><img src="img/1.jpeg" alt=""></li>
<li><img src="img/2.jpeg" alt=""></li>
<li><img src="img/3.jpeg" alt=""></li>
<li><img src="img/4.jpeg" alt=""></li>
<li><img src="img/5.jpeg" alt=""></li>
<li><img src="img/6.jpeg" alt=""></li>
<li><img src="img/7.jpeg" alt=""></li>
<li><img src="img/8.jpeg" alt=""></li>
<li><img src="img/9.jpeg" alt=""></li>
<li><img src="img/10.jpeg" alt=""></li>
<li><img src="img/11.jpeg" alt=""></li>
<li><img src="img/12.jpeg" alt=""></li>
<li><img src="img/13.jpeg" alt=""></li>
<li><img src="img/14.jpeg" alt=""></li>
<li><img src="img/15.jpeg" alt=""></li>
</ul>
</body>
</html>
柵格
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<title>test</title>
<style>
#grid-demo{
width: 1000px;
margin: 0 auto;
}
.grid{
display: flex;
margin: 20px 0;
height: 60px;
}
.grid .grid-item{
flex-grow: 1;
background-color: #eee;
height: 60px;
line-height: 60px;
font-size: 26px;
width: 5%;
text-align: center;
margin: 0 10px;
}
.grid .col-10{
flex-basis: 83.3333%
}
.grid .col-8{
flex-basis: 66.6666%;
}
.grid .col-6{
flex-basis: 50%;
}
.grid .col-4{
flex-basis: 33.3333%;
}
.grid .col-3{
flex-basis: 25%;
}
.grid .col-2{
flex-basis: 16.6667%;
}
</style>
</head>
<body>
<div id="grid-demo">
<div class="grid">
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
<div class="grid-item">1</div>
</div>
<div class="grid">
<div class="grid-item">2</div>
<div class="grid-item">2</div>
<div class="grid-item">2</div>
<div class="grid-item">2</div>
<div class="grid-item">2</div>
<div class="grid-item">2</div>
</div>
<div class="grid">
<div class="grid-item">3</div>
<div class="grid-item">3</div>
<div class="grid-item">3</div>
<div class="grid-item">3</div>
</div>
<div class="grid">
<div class="grid-item">4</div>
<div class="grid-item">4</div>
<div class="grid-item">4</div>
</div>
<div class="grid">
<div class="grid-item">6</div>
<div class="grid-item">6</div>
</div>
<div class="grid">
<div class="grid-item col-8">8</div>
<div class="grid-item col-4">4</div>
</div>
<div class="grid">
<div class="grid-item">12</div>
</div>
</div>
</body>
</html>
固定底欄
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<title>test</title>
<style>
body{
margin: 0;
padding: 0;
}
#demo{
display: flex;
flex-direction: column;
min-height: 100vh;
}
header, footer{
height: 100px;
background-color: darkblue;
color: white;
text-align: center;
line-height: 100px;
}
.flex-body{
flex-grow: 1;
}
</style>
</head>
<body>
<div id="demo">
<header>I am header!</header>
<div class="flex-body">I am body!</div>
<footer>I am footer!</footer>
</div>
</body>
</html>