前端布局之Flex布局

Posted 2021-03-09 m-littlebird

tags:

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1.内容水平排列-左对齐

需要在父节点上添加：display:flex;表示使用Flex布局。

flex-direction:row; /* 表示内容直接横排列 */

<!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>
        div{
            display:flex;
            width: 80%;
            height: 300px;
            background-color: pink;
             /* 默认的主轴是 x 轴 行 row  那么y轴就是侧轴喽 */
            /* 我们的元素是跟着主轴来排列的 */
            flex-direction:row; /* 表示内容直接横排列 */
        }
        div span{
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>
</body>
</html>

2.内容横排列-反转右对齐

flex-direction:row-reverse

<!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>
        div{
            display:flex;
            width: 80%;
            height: 300px;
            background-color: pink;
             /* 默认的主轴是 x 轴 行 row  那么y轴就是侧轴喽 */
            /* 我们的元素是跟着主轴来排列的 */
            flex-direction:row-reverse; /* 表示内容直接横排列 */
        }
        div span{
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>
</body>
</html>

3.垂直排列

flex-direction: column;

<!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>
        div{
            display:flex;
            width: 80%;
            height: 300px;
            background-color: pink;
             /* 默认的主轴是 x 轴 行 row  那么y轴就是侧轴喽 */
            /* 我们的元素是跟着主轴来排列的 */
            /* flex-direction:row; 表示内容直接横排列 */
            flex-direction: column;

        }
        div span{
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>
</body>
</html>

4.左对齐

justify-content:flex-start

<!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>
                div {
            display: flex;
            width: 800px;
            height: 300px;
            background-color: pink;
            /* 默认的主轴是 x 轴 row */
            flex-direction: row;
            /* justify-content: 是设置主轴上子元素的排列方式 */
            /* justify-content: flex-start; */
            /* justify-content: flex-end; */
            /* 让我们子元素居中对齐 */
            /* justify-content: center; */
            /* 平分剩余空间 */
            /* justify-content: space-around; */
            /* 先两边贴边， 在分配剩余的空间 */
            justify-content:flex-start
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
    </div>
</body>
</html>

5.右对齐

justify-content:flex-end

<!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>
                div {
            display: flex;
            width: 800px;
            height: 300px;
            background-color: pink;
            /* 默认的主轴是 x 轴 row */
            flex-direction: row;
            /* justify-content: 是设置主轴上子元素的排列方式 */
            /* justify-content: flex-start; */
            /* justify-content: flex-end; */
            /* 让我们子元素居中对齐 */
            /* justify-content: center; */
            /* 平分剩余空间 */
            /* justify-content: space-around; */
            /* 先两边贴边， 在分配剩余的空间 */
            justify-content:flex-end
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
    </div>
</body>
</html>

6.居中对齐

justify-content:center

<!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>
                div {
            display: flex;
            width: 800px;
            height: 300px;
            background-color: pink;
            /* 默认的主轴是 x 轴 row */
            flex-direction: row;
            /* justify-content: 是设置主轴上子元素的排列方式 */
            /* justify-content: flex-start; */
            /* justify-content: flex-end; */
            /* 让我们子元素居中对齐 */
            /* justify-content: center; */
            /* 平分剩余空间 */
            /* justify-content: space-around; */
            /* 先两边贴边， 在分配剩余的空间 */
            justify-content:center
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
    </div>
</body>
</html>

7.平均分配

justify-content:space-around

<!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>
                div {
            display: flex;
            width: 800px;
            height: 300px;
            background-color: pink;
            /* 默认的主轴是 x 轴 row */
            flex-direction: row;
            /* justify-content: 是设置主轴上子元素的排列方式 */
            /* justify-content: flex-start; */
            /* justify-content: flex-end; */
            /* 让我们子元素居中对齐 */
            /* justify-content: center; */
            /* 平分剩余空间 */
            /* justify-content: space-around; */
            /* 先两边贴边， 在分配剩余的空间 */
            justify-content:space-around
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
    </div>
</body>
</html>

8.左右对齐

justify-content:space-between

<!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>
                div {
            display: flex;
            width: 800px;
            height: 300px;
            background-color: pink;
            /* 默认的主轴是 x 轴 row */
            flex-direction: row;
            /* justify-content: 是设置主轴上子元素的排列方式 */
            /* justify-content: flex-start; */
            /* justify-content: flex-end; */
            /* 让我们子元素居中对齐 */
            /* justify-content: center; */
            /* 平分剩余空间 */
            /* justify-content: space-around; */
            /* 先两边贴边， 在分配剩余的空间 */
            justify-content:space-between
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
    </div>
</body>
</html>

9.垂直均分

/* 我们现在的主轴是y轴 */

flex-direction: column;

/* justify-content: center; */

justify-content: space-between;

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div {
            display: flex;
            width: 800px;
            height: 400px;
            background-color: pink;
            /* 我们现在的主轴是y轴 */
            flex-direction: column;
            /* justify-content: center; */
            justify-content: space-between;
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>

<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>
</body>

</html>

10.换行设置

flex-wrap: wrap; 默认是不换行的 /* flex-wrap: nowrap; */

<!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>
        div{
            display:flex;
            width: 600px;
            height: 400px;
            background-color: pink;
            /* flex布局中，默认的子元素是不换行的， 如果装不开，会缩小子元素的宽度，放到父元素里面  */
            /* flex-wrap: nowrap; */
            flex-wrap: wrap;
        }
        div span{
            width: 150px;
            height: 100px;
            background-color: purple;
            color: #fff;
            margin: 10px;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
        <span>5</span>
    </div>
</body>
</html>

11.内容水平垂直居中

flex-direction: column;

justify-content: center;

/* 我们需要一个侧轴居中 */

/* 拉伸，但是子盒子不要给高度 */

/* align-items: stretch; */

align-items:center;

/* align-content: center; */

主要用来设置在侧抽上的对齐方式

<!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>
                div {
            display: flex;
            width: 800px;
            height: 400px;
            background-color: pink;
            /* 默认的主轴是 x 轴 row */
            flex-direction: column;
            justify-content: center;
            /* 我们需要一个侧轴居中 */
            /* 拉伸，但是子盒子不要给高度 */
            /* align-items: stretch; */
            align-items:center;
            /* align-content: center; */
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
            color: #fff;
            margin: 10px;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </div>
</body>
</html>

12.多行对齐方式

align-content:center;

主要是多行对齐方式：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div {
            display: flex;
            width: 800px;
            height: 400px;
            background-color: pink;
            /* 换行 */
            flex-wrap: wrap;
            /* 因为有了换行，此时我们侧轴上控制子元素的对齐方式我们用 align-content */
            /* align-content: flex-start; */
            /* align-content: center; */
            /* align-content: space-between; */
            align-content:center;
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
            color: #fff;
            margin: 10px;
        }
    </style>
</head>

<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
        <span>5</span>
        <span>6</span>
    </div>
</body>

</html>

13.复合属性

/* flex-direction: column;

flex-wrap: wrap; */

/* 把设置主轴方向和是否换行（换列）简写 */

flex-flow: column wrap;

主要用于简写是有 flex-direction flex-wrap 两个属性

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div {
            display: flex;
            width: 600px;
            height: 300px;
            background-color: pink;
            /* flex-direction: column;
            flex-wrap: wrap; */
            /* 把设置主轴方向和是否换行（换列）简写 */
            flex-flow: column wrap;
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
        }
    </style>
</head>

<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
        <span>5</span>
    </div>
</body>

</html>

14.flex子元素属性

flex: 1; 主要表示该元素占几份

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        section {
            display: flex;
            width: 60%;
            height: 150px;
            background-color: pink;
            margin: 0 auto;
        }

        section div:nth-child(1) {
            width: 100px;
            height: 150px;
            background-color: red;
        }

        section div:nth-child(2) {
            flex: 1;
            background-color: green;
        }

        section div:nth-child(3) {
            width: 100px;
            height: 150px;
            background-color: blue;
        }

        p {
            display: flex;
            width: 60%;
            height: 150px;
            background-color: pink;
            margin: 100px auto;
        }

        p span {
            flex: 1;
        }

        p span:nth-child(2) {
            flex: 2;
            background-color: purple;
        }
    </style>
</head>

<body>
    <section>
        <div></div>
        <div></div>
        <div></div>
    </section>
    <p>
        <span>1</span>
        <span>2</span>
        <span>3</span>
    </p>
</body>

</html>

15.子元素order和align-self

order: -1;表示交换位置跟之间的几个原型进行位置交换。

align-self: flex-end; 当前元素的位置。

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div {
            display: flex;
            width: 80%;
            height: 300px;
            background-color: pink;
            /* 让三个子盒子沿着侧轴底侧对齐 */
            /* align-items: flex-end; */
            /* 我们想只让3号盒子下来底侧 */
        }

        div span {
            width: 150px;
            height: 100px;
            background-color: purple;
            margin-right: 5px;
        }

        div span:nth-child(2) {
            /* 默认是0   -1比0小所以在前面 */
            order: -1;
        }

        div span:nth-child(3) {
            align-self: flex-end;
        }
    </style>
</head>

<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>4</span>
    </div>
</body>

</html>

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