Bootstrap 4 - 网格系统

描述

Bootstrap 4 网格系统使用Flexbox构建，完全响应式，通过在页面上创建行和列的布局，可扩展到 12 列（根据设备的大小）。它提供响应式、移动优先的流体网格系统，可随着设备或视口尺寸的增加而缩放列。

网格系统的工作

  • 行必须放置在.container类中，以便正确对齐和填充。

  • 对于响应式宽度，请使用.container类；对于所有视口的固定宽度，请使用.container-fluid类。

  • 使用行创建水平列组。

  • 内容应放置在列内，并且只有列可以是行的直接子级。

  • 列包含用于控制列之间空间的填充。

  • 如果一行中放置的列超过 12 列，则这些列将放置在新行中。

  • 列通过填充在列内容之间创建间隙。因此，您可以使用行上的.no-gutters类删除行中的边距和列中的填充。

  • 您可以通过使用五个网格断点（例如超小、小、中、大和特大）使网格系统具有响应能力。

  • 预定义的网格类（如 .col-4）可用于快速制作网格布局。LESS mixin 也可用于更多语义布局。

网格选项

下表总结了 Bootstrap 4 网格系统如何跨多个设备工作的各个方面 -

超小型设备 (<576px) 小型设备（≥576px） 中型设备（≥768px） 大型设备（≥992px） 超大设备（≥1200px）
网格Behave 始终水平 折叠开始，水平位于断点上方 折叠开始，水平位于断点上方 折叠开始，水平位于断点上方 折叠开始，水平位于断点上方
最大集装箱宽度 无（自动） 540像素 720像素 960像素 1140像素
班级班级 .col- .col-sm- .col-md- .col-lg- .col-xl-
列数 12 12 12 12 12
天沟宽度

30像素

（列每边 15 像素）

30像素

（列每边 15 像素）

30像素

（列每边 15 像素）

30像素

（列每边 15 像素）

30像素

（列每边 15 像素）
可嵌套 是的 是的 是的 是的 是的
列排序 是的 是的 是的 是的 是的

基本网格结构

以下是 Bootstrap 4 网格的基本结构 -

<div class = "container">
   <div class = "row">
      <div class = "col-*-*"></div>
      <div class = "col-*-*"></div>
   </div>
   
   <div class = "row">
      <div class = "col-*-*"></div>
      <div class = "col-*-*"></div>
      <div class = "col-*-*"></div>	  
   </div>
   
   <div class = "row">...</div>
</div>

网格系统示例

以下是 Bootstrap 4 网格系统的示例 -

例子

现场演示 
<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = "stylesheet" 
         href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" 
         crossorigin = "anonymous">
      <title>Bootstrap 4 Example</title>
      </style>
         .grid_system  div[class^="col"] {
            border: 1px solid white;
            background: #e4dcdc;
            text-align: center;
            padding-top: 5px;
            padding-bottom: 5px
         }
      </style>
   </head>
   
   <body>
      <div class = "grid_system">
         <div class = "row">
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
            <div class = "col-sm-1">.col-sm-1</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-3">.col-sm-3</div>
            <div class = "col-sm-3">.col-sm-3</div>
            <div class = "col-sm-3">.col-sm-3</div>
            <div class = "col-sm-3">.col-sm-3</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-4">.col-sm-4</div>
            <div class = "col-sm-4">.col-sm-4</div>
            <div class = "col-sm-4">.col-sm-4</div>
         </div>
         
         <div class = "row">
            <div class =" col-sm-3">.col-sm-3</div>
            <div class = "col-sm-3">.col-sm-3</div>
            <div class = "col-sm-6">.col-sm-6</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-5">.col-sm-5</div>
            <div class = "col-sm-7">.col-sm-7</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-6">.col-sm-6</div>
            <div class = "col-sm-6">.col-sm-6</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-12">.col-sm-12</div>
         </div>
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js"
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它将产生以下结果 -

输出

创建两列布局

以下示例描述了为小型、中型和大型设备创建两个列布局。在手机等小型设备上，默认情况下，列将自动变为水平。

例子

现场演示 
<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = "stylesheet" href = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" 
         crossorigin = "anonymous">
      <title>Bootstrap 4 Example</title>
   </head>
   
   <body>
      <div class = "grid_system">
         <div class = "row">
            <div class = "col-sm-6">.col-sm-6</div>
            <div class = "col-sm-6">.col-sm-6</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-7">.col-sm-7</div>
            <div class = "col-sm-5">.col-sm-5</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-4">.col-sm-4</div>
            <div class = "col-sm-8">.col-sm-8</div>
         </div>
		 
         <div class = "row">
            <div class = "col-sm-9">.col-sm-9</div>
            <div class = "col-sm-3">.col-sm-3</div>
         </div>
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js" 
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它将产生以下结果 -

输出

创建三列布局

以下示例描述了为中型和大型设备创建三列布局。如果屏幕分辨率大于或等于 992 像素，那么它将在平板电脑中以横向模式显示，并且像往常一样，它将以纵向模式显示。

例子

现场演示 
<html lang = "en">
   <head>
      <!-- Meta tags -->
      <meta charset = "utf-8">
      <meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
      
      <!-- Bootstrap CSS -->
      <link rel = " stylesheet" href = " https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" 
         integrity = "sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO"
         crossorigin = "anonymous">
      <title>Bootstrap 4 Example</title>
   </head>
   
   <body>
      <div class = "grid_system">
         <div class = "row">
            <div class = "col-sm-4">.col-sm-4</div>
            <div class = "col-sm-4">.col-sm-4</div>
            <div class = "col-sm-4">.col-sm-4</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-3">.col-sm-3</div>
            <div class = "col-sm-4">.col-sm-4</div>
            <div class = "col-sm-5">.col-sm-5</div>
         </div>
         
         <div class = "row">
            <div class = "col-sm-2">.col-sm-2</div>
            <div class = "col-sm-8">.col-sm-8</div>
            <div class = "col-sm-2">.col-sm-2</div>
         </div>
		
         <div class = "row">
            <div class = "col-sm-2">.col-sm-2</div>
            <div class = "col-sm-3">.col-sm-3</div>
            <div class = "col-sm-7">.col-sm-7</div>
         </div>
      </div>
      
      <!-- jQuery first, then Popper.js, then Bootstrap JS -->
      <script src = "https://code.jquery.com/jquery-3.3.1.slim.min.js" 
         integrity = "sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" 
         integrity = "sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" 
         crossorigin = "anonymous">
      </script>
      
      <script src = "https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" 
         integrity = "sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" 
         crossorigin = "anonymous">
      </script>
      
   </body>
</html>

它将产生以下结果 -

输出