HTML基础第六课(冲浪笔记6)

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今天的主题只有一个,那就是Flex布局!!!

一、简单使用display: flex;

1、 没有任何布局的情况下代码及效果

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
        }
        .item2{
            background-color: yellow;
        }
        .item3{
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

image.png

2、 display: flex; 默认使其横向排列(注意编写位置在父级)

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
            display: flex;
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
        }
        .item2{
            background-color: yellow;
        }
        .item3{
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

image.png

二、排列方向flex-direction
1、flex-direction: row; 默认从左到右
2、flex-direction: row-reverse; 从右到左
3、flex-direction: column; 从上到下
4、flex-direction: column-reverse; 从下到上

image.png

三、换行 flex-wrap\

1、 flex-wrap: nowrap; 当内容过多,会自动缩小内容,不会自动换行(默认不换行)
2、 flex-wrap: wrap; 换行
3、 flex-wrap: wrap-reverse; 反向换行
4、 换行也放不下时就会溢出

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
            display: flex;
            /* flex-wrap: nowrap; */
            flex-wrap: wrap;
            /* flex-wrap: wrap-reverse; */
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
        }
        .item2{
            background-color: yellow;
        }
        .item3{
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

image.png

四、 主轴
1、x轴justify-content
(1)justify-content: flex-start; 默认x轴起点为开头
(2)justify-content: flex-end; x轴结尾为开头
注意:区别于flex-direction: row-reverse; 的排列顺序(色块摆放顺序的不同)

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
            display: flex;
            /* flex-direction: row-reverse; */
            /* justify-content: flex-end; */
            /* justify-content: center; */
            /* justify-content: space-around; */
            /* justify-content: space-between; */
            justify-content: space-evenly;
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
        }
        .item2{
            background-color: yellow;
        }
        .item3{
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

①justify-content: flex-end;

image.png

② flex-direction: row-reverse;

image.png (3)justify-content: center; 居中

image.png (4)justify-content: space-around; 中间缝隙是旁边缝隙的两倍

image.png

(5)justify-content: space-between; 旁边无缝隙【比较常用,有内部撑开的效果】

image.png

(6)justify-content: space-evenly; 中间旁边间隙一样

image.png

2、交叉轴(y轴)align-items
(1)在没有将标签高度写定的情况下,可以用align-items: stretch; 填满y轴(y轴拉伸至铺满)
(2)align-items: flex-start; 交叉轴方向开头
(3)align-items: flex-end; 交叉轴方向结尾
(4)align-items: center; 交叉轴方向中心

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
            display: flex;
            /* align-items: stretch; */
            /* align-items: flex-start; */
            /* align-items: flex-end; */
            align-items: center;
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
        }
        .item2{
            background-color: yellow;
        }
        .item3{
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

image.png

3、多个主轴align-content
(1)align-content: flex-start; 默认位于容器开头
(2)align-content: flex-end; 位于容器结尾
(3)align-content: center; 位于容器中心
(4)align-content: space-between; 内容之间留空白,左右对齐,剩下的空间平分为缝隙

image.png

(5)align-content: space-around; 内容之前、之间、之后留空白,容器开始和结束的缝隙宽度是项目之间缝隙的两倍

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
            display: flex;
            flex-wrap: wrap;
            /* align-content: flex-start; */
            /* align-content: flex-end; */
            /* align-content: center; */
            /* align-content: space-between; */
            align-content: space-around;
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
        }
        .item2{
            background-color: yellow;
        }
        .item3{
            background-color: skyblue;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

image.png

 五、项目\

1、 order属性:项目排列顺序,数值越小,排列越靠前,默认值为0

注意:这时候编写的位置是子级,自己的标签内

image.png

2、 flex-grow 放大比例(剩余空间按比例分配),默认值为0,不放大

<!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>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 500px;
            height: 500px;
            border: 10px solid blue;
            margin: auto;
            display: flex;
        }
        .item1,.item2,.item3{/* 同时设置多个标签相同属性 */
            height: 100px;
            width: 100px;
        }
        .item1{
            background-color: red;
            order: 3;
            flex-grow: 2;
        }
        .item2{
            background-color: yellow;
            order: 1;
            flex-grow: 2;
        }
        .item3{
            background-color: skyblue;
            order: 2;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1"></div>
        <div class="item2"></div>
        <div class="item3"></div>
    </div>
</body>
</html>

image.png

3、 flex-shrink 缩小比例,默认为1,自动缩小

4、 flex-basis 设置项目宽度,内容超出范围会自动变大

5、 align-self 允许单个项目与其他项目有不同的对齐方式