组成
弹性盒子没有设置高，就会自动拉伸
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-组成</title>
<style>
/* 弹性容器 */
.box {
display: flex;
height: 300px;
border: 1px solid #000;
}
/* 弹性盒子：沿着主轴方向排列 */
.box div {
width: 200px;
/* height: 100px; */
background-color: pink;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
<div>1</div>
<div>2</div>
<div>3</div>
<div>1</div>
<div>2</div>
<div>3</div>
</div>
</body>
</html>
主轴对齐方式
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-主轴对齐方式</title>
<style>
.box {
display: flex;
/* justify-content: flex-start; */
/* justify-content: flex-end; */
/* 居中 */
/* justify-content: center; */
/* 父级剩余的尺寸分配成间距 */
/* 弹性盒子之间的间距相等 */
/* justify-content: space-between; */
/* 间距出现在弹性盒子两侧 */
/* 视觉效果：弹性盒子之间的间距是两端间距的2倍 */
/* justify-content: space-around; */
/* 各个间距都相等 */
justify-content: space-evenly;
height: 300px;
border: 1px solid #000;
}
.box div {
width: 200px;
height: 100px;
background-color: pink;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
</div>
</body>
</html>
侧轴对齐方式
如果没有设置侧轴对齐方式和弹性盒子的高度，默认是stretch。
这也是为什么上面有提到，高度没设置会自动拉伸的原因
<!DOCTYPE html>
<html lang="en"><head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-侧轴对齐方式</title>
<style>
.box {
display: flex;
/* 弹性盒子在侧轴方向没有尺寸才能拉伸 */
/* align-items: stretch; */
/* align-items: center; */
/* align-items: flex-start; */
align-items: flex-end;
height: 300px;
border: 1px solid #000;
}
/* 第二个div，侧轴居中对齐 */
.box div:nth-child(2) {
align-self: center;
}
.box div {
width: 200px;
height: 100px;
background-color: pink;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
</div>
</body></html>
修改主轴方向
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-修改主轴方向</title>
<style>
.box {
display: flex;
/* 修改主轴方向 垂直方向；侧轴自动变换到水平方向 */
flex-direction: column;
/* 主轴在垂直，视觉效果：垂直居中 */
justify-content: center;
/* 侧轴在水平，视觉效果：水平居中 */
align-items: center;
width: 150px;
height: 120px;
background-color: pink;
}
img {
width: 32px;
height: 32px;
}
</style>
</head>
<body>
<div class="box">
<img src="./images/1.png" alt="">
<span>媒体</span>
</div>
</body>
</html>弹性伸缩比
注意！使用弹性伸缩比，控制的是主轴方向！
<!DOCTYPE html>
<html lang="en"><head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-弹性伸缩比</title>
<style>
/* 默认情况下，主轴方向尺寸是靠内容撑开；侧轴默认拉伸 */
.box {
display: flex;
flex-direction: column;
height: 300px;
border: 1px solid #000;
}
.box div {
/* height: 100px; */
background-color: pink;
}
.box div:nth-child(1) {
width: 200px;
}
.box div:nth-child(2) {
flex: 1;
}
.box div:nth-child(3) {
flex: 2;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
</div>
</body></html>可以看到盒子3的高度是盒子2的两倍
为什么？
因为总份数 = 1+2，盒子2占了一份，盒子3占了两份
弹性盒子换行
想自动换行，在父级加wrap即可
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-弹性换行</title>
<style>
.box {
display: flex;
flex-wrap: wrap;
/* 不换行 */
/* flex-wrap: nowrap; */
justify-content: space-between;
height: 300px;
border: 1px solid #000;
}
.box div {
width: 200px;
height: 100px;
background-color: pink;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
<div>6</div>
<div>7</div>
<div>8</div>
<div>9</div>
<div>10</div>
<div>11</div>
<div>12</div>
</div>
</body>
</html>
行对齐方式
<!DOCTYPE html>
<html lang="en"><head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>flex布局-行对齐方式</title>
<style>
.box {
display: flex;
flex-wrap: wrap;
justify-content: space-between;
/* 调整 行对齐方式：对单行弹性盒子不生效 */
/* align-content: flex-start; */
/* align-content: flex-end; */
/* align-content: center; */
/* align-content: space-between; */
/* align-content: space-around; */
/* 没有代码提示 */
align-content: space-evenly;
height: 400px;
border: 1px solid #000;
}
.box div {
width: 200px;
height: 100px;
background-color: pink;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div>5</div>
<div>6</div>
<div>7</div>
<div>8</div>
</div>
</body></html>
综合案例
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
/* 盒子自动内减 */
}
li {
list-style: none;
}
.box {
border: 1px solid black;
width: 1200px;
height: 418px;
border-radius: 10px;
/* 直角变圆角 */
margin: 50px auto;
/* 和上面产生距离50px，水平居中 */
}
.box ul {
display: flex;
flex-wrap: wrap;
justify-content: space-between;
align-content: space-between;
padding: 90px 40px 90px 60px;
/* 左上右下 */
height: 418px;
}
.box li {
width: 500px;
height: 88px;
/* background-color: pink; */
display: flex;
flex-wrap: wrap;
}
.box .pic {
margin-right: 15px;
}
.box .text h4 {
/* 文字行高等于上边距+下边距+文字高 */
line-height: 40px;
font-size: 20px;
font-weight: 400;
/* 文字粗细 */
color: #333;
}
.box .text p {
font-size: 14px;
color: #666;
}
</style>
</head>
<body>
<div class="box">
<ul>
<li>
<div class="pic">
<img src="./p1.png" alt="">
</div>
<div class="text">
<h4>一键发布多端</h4>
<p>发布视频到抖音短视频、西瓜视频及今日头条</p>
</div>
</li>
<li>
<div class="pic">
<img src="./p2.png" alt="">
</div>
<div class="text">
<h4>管理视频内容</h4>
<p>支持修改已发布稿件状态和实时查询视频审核状态</p>
</div>
</li>
<li>
<div class="pic">
<img src="./p3.png" alt="">
</div>
<div class="text">
<h4>发布携带组件</h4>
<p>支持分享内容携带小程序、地理位置信息等组件
</p>
</div>
</li>
<li>
<div class="pic">
<img src="./p4.png" alt="">
</div>
<div class="text">
<h4>数据评估分析</h4>
<p>获取视频在对应产品内的数据表现、获取抖音热点</p>
</div>
</li>
</ul>
</div>
</body>
</html>
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