flex的基础知识
基础概念可以参考： https://www.ruanyifeng.com/blog/2015/07/flex-grammar.html
1.两列布局
效果
代码:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>两列布局</title> <style> *{ margin: 0; padding: 0; } .box { display: flex; height: 200px; } .left { background-color: yellow; /* flex-basis定义该项目在分配主轴空间之前提前获得200px的空间 */ flex-basis: 200px; /* flex-grow定义该项目不分配剩余空间 */ flex-grow: 0; } /*.center {*/ /* background-color: red;*/ /* !* flex-basis定义该项目在分配主轴空间之前提前获得200px的空间 *!*/ /* flex-basis: 500px;*/ /* !* flex-grow定义该项目不分配剩余空间 *!*/ /* flex-grow: 0;*/ /*}*/ .main { background-color: green; /* flex-grow定义main占满剩余空间 */ flex-grow: 1; } </style> </head> <body> <div class="box"> <div class="left">left</div> <!-- <div class="center">center</div>--> <div class="main">main</div> </div> </body> </html>
2.水平/垂直居中
效果:
代码:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>水平/垂直居中</title> <style> .box { display: flex; justify-content: center; align-items: center; height: 500px; width: 500px; background-color: green; } .content { height: 200px; width: 200px; background-color: yellow; line-height: 200px; text-align: center; } </style> </head> <body> <div class="box"> <div class="content">我是子元素，我要垂直居中</div> </div> </body> </html>
3.两栏/三栏布局
效果:
coding:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>两栏/三栏布局</title> </head> <style> * { padding: 0; margin: 0; } .box { display: flex; height: 200px; margin-bottom: 30px; } .left { background-color: yellow; flex-basis: 200px; /* flex-basis定义该项目在分配主轴空间之前提前获得200px的空间 */ flex-grow: 0; /* flex-grow定义该项目不分配剩余空间 */ } .main { background-color: green; flex-grow: 1; /* flex-grow定义main占满剩余空间 */ } .right { background-color: blue; flex-basis: 100px; flex-grow: 0; } </style> <body> <div class="box"> <div class="left">left</div> <div class="main">main</div> </div> <div class="box"> <div class="left">left</div> <div class="main">main</div> <div class="right">right</div> </div> </body> </html>
4.等分宽高
code:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>等分宽高</title> </head> <style> * { margin: 0; padding: 0; } nav { display: flex; } a { flex-grow: 1; font-size: 30px; text-decoration: none; text-align: center; } nav a:nth-child(odd){ background: pink; } nav a:nth-child(even){ background: goldenrod; } </style> <body> <nav> <a href="#">中</a> <a href="#">华</a> <a href="#">人</a> <a href="#">民</a> <a href="#">共</a> <a href="#">和</a> <a href="#">国</a> </nav> </body> </html>
5.圣杯布局
效果:
code:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>圣杯布局</title> </head> <style> * { margin: 0; padding: 0; } .box { display: flex; flex-direction: column; width: 100%; height: 500px; background-color: yellow; text-align: center; font-size: 30px; min-height:100vh; } header, footer { flex: 0 0 80px; line-height: 80px; background: pink; } .content { display: flex; flex: 1; } nav { order: -1; background-color: blue; flex: 0 0 80px; } aside { background-color: green; flex: 0 0 80px; } main { flex: 1; } </style> <body> <div class="box"> <header>header</header> <div class="content"> <main>main</main> <nav>nav</nav> <aside>aside</aside> </div> <footer>footer</footer> </div> </body> </html>
6.流式布局
效果:
code
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>流式布局</title> </head> <style> .box { display: flex; flex-flow: row wrap; height: 300px; width: 400px; background-color: yellow; } .content { flex: 0 0 25%; background-color: blue; border: 2px solid red; box-sizing: border-box; } </style> <body> <h1>10个</h1> <div class="box"> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> <div class="content"></div> </div> </body> </html>
7.基于flex的响应式布局
效果图
屏幕尺寸大于640px
高度不够4个盒子的总和时
屏幕尺寸小于640px时
code:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>结合响应式布局的综合运用</title> </head> <style> * { padding: 0; margin: 0; } .box div { width: 150px; padding: 20px; } .box1 { height: 120px; background-color: red; } .box2 { height: 100px; background-color: blue; } .box3 { height: 40px; background-color: pink; } .box4 { height: 200px; background-color: yellow; } @media (min-width: 640px) { .box { display: flex; flex-direction: row; justify-content: space-between; align-items: center; } } @media (max-width: 640px) { .box { display: flex; flex-direction: row; align-items: flex-start; justify-content: space-between; flex-wrap: wrap; } .box4 { order: -1; } } </style> <body> <div class="box"> <div class="box1"></div> <div class="box2"></div> <div class="box3"></div> <div class="box4"></div> </div> </body> </html>
