【前端】响应式布局笔记—

【前端】响应式布局笔记——flex

二、Flex

Flex(FlexiableBox:弹性盒子，用于弹性布局，配合rem处理尺寸的适配问题)。

1、flex-direction:子元素在父元素盒子中的排列方式。

父级元素添加：flex-direction: row;
在这里插入图片描述
父级元素添加：flex-direction: row-reverse;

父级元素添加：flex-direction: column;

父级元素添加：flex-direction: column-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>
        .father{
            background-color: antiquewhite;
            width: 100%;
            height: 400px;
            display: flex;
            /* flex-direction: row; */
            /* flex-direction: row-reverse; */
            /* flex-direction: column; */
            flex-direction: column-reverse;
        }
        .child{
            width: 100px;
            height: 100px;
            background-color: azure;
            font-size: 30px;
            text-align: center;
            line-height: 100px;
            border: 1px solid;
        }
    </style>
</head>
<body>
    <div class="father">
        <div class="child">1</div>
        <div class="child">2</div>
        <div class="child">3</div>
        <div class="child">4</div>
    </div>
</body>
</html>

2、flex-wrap：子元素换行

已1为基础父元素设置flex-direction: row;无论我子元素设置多少个，子元素（已设置宽
、高）会被压缩。如下子元素被压缩图，添加 flex-wrap: wrap;子元素不会被压缩而且还会自动换行。
在这里插入图片描述

<!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>
        .father{
            background-color: antiquewhite;
            width: 100%;
            height: 400px;
            display: flex;
            flex-direction: row;
            /* 不换行 */
            /* flex-wrap: nowrap; */
            /* 换行 */
            flex-wrap: wrap;
            /* 换行，且子元素排列顺序相反 */
            /* flex-wrap: wrap-reverse; */

        }
        .child{
            width: 300px;
            height: 200px;
            background-color: azure;
            font-size: 30px;
            text-align: center;
            line-height: 100px;
            border: 1px solid;
        }
    </style>
</head>
<body>
    <div class="father">
        <div class="child">1</div>
        <div class="child">2</div>
        <div class="child">3</div>
        <div class="child">4</div>
        <div class="child">5</div>
        <div class="child">6</div>
        <div class="child">7</div>
    </div>
</body>
</html>

3、flex-flow 等价于flex-direction+flex-wrap；

<!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>
        .father{
            background-color: antiquewhite;
            width: 100%;
            height: 400px;
            display: flex;
            flex-flow: row wrap;
        }
        .child{
            width: 300px;
            height: 200px;
            background-color: azure;
            font-size: 30px;
            text-align: center;
            line-height: 100px;
            border: 1px solid;
        }
    </style>
</head>
<body>
    <div class="father">
        <div class="child">1</div>
        <div class="child">2</div>
        <div class="child">3</div>
        <div class="child">4</div>
        <div class="child">5</div>
        <div class="child">6</div>
        <div class="child">7</div>
    </div>
</body>
</html>

4、justify-content（常用）

justify-content: flex-start;元素从左到右排列。
在这里插入图片描述
justify-content: flex-end;元素从右到左。

justify-content: center;元素居中。

justify-content: space-around;平均分布，两边留有一半的间隔。

justify-content:space-between;平均分布，两边不留间隔。