Bootstrap整体框架之CSS12栅格系统

1.整体架构

BootStrap框架公共六个部分：(css组件和js插件是其表现形式，其余的是基础支撑平台)

表现形式
CSS组件
JS插件
基础支撑平台
CSS12栅格系统
基础布局组件
jQuery
响应式设计

1.1 CSS12栅格系统

12栅格系统是BootStrap的核心功能，也是响应式设计核心理念的一个实现方式。

1.1.1 实现原理

栅格布局原理：定义容器大小，平分12分，在调整内外边距，最后结合媒体查询，制作出强大响应式的栅格系统。

1.最外层的边框，伴随着响应式思想，区分了四种类型浏览器，像素分界点768px、992px、1200px
2.第二层的边框，即.container样式容器，针对四种浏览器宽度不一样，值是自动、750px、970px、1170px

//源码
  .container {
   padding-right: 15px;
   padding-left: 15px;
   margin-right: auto;
   margin-left: auto;
  }
  @media (min-width: 768px) {
   .container {
    width: 750px;
   }
  }
  @media (min-width: 992px) {
   .container {
    width: 970px;
   }
  }
  @media (min-width: 1200px) {
   .container {
    width: 1170px;
   }
  }

3.1号横条，左内边距和右内边距是15px，是12个col-lg-1，没有row，则会

//源码
.col-xs-1, .col-sm-1, .col-md-1, .col-lg-1, .col-xs-2, .col-sm-2, .col-md-2, .col-lg-2, .col-xs-3, .col-sm-3, .col-md-3, .col-lg-3, .col-xs-4, .col-sm-4, .col-md-4, .col-lg-4, .col-xs-5, .col-sm-5, .col-md-5, .col-lg-5, .col-xs-6, .col-sm-6, .col-md-6, .col-lg-6, .col-xs-7, .col-sm-7, .col-md-7, .col-lg-7, .col-xs-8, .col-sm-8, .col-md-8, .col-lg-8, .col-xs-9, .col-sm-9, .col-md-9, .col-lg-9, .col-xs-10, .col-sm-10, .col-md-10, .col-lg-10, .col-xs-11, .col-sm-11, .col-md-11, .col-lg-11, .col-xs-12, .col-sm-12, .col-md-12, .col-lg-12 {
   position: relative;
   min-height: 1px;
   padding-right: 15px;
   padding-left: 15px;
  }

 <!DOCTYPE html>
  <html lang="en">
   <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- Bootstrap从3.0版本开始全面支持移动平台，贯彻移动先行宗旨 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <title>Bootstrap 101 Template</title>

    <!-- Bootstrap -->
    <link href="bootstrap-3.3.7-dist/css/bootstrap.min.css" rel="stylesheet">

   </head>
   <body>
    <div class="container" style="border:1px solid black">
        <div class="col-lg-1" style="border:1px solid black">col-lg-1</div>
        <div class="col-lg-1" style="border:1px solid black">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1" style="border:1px solid black">col-lg-1</div>
    </div>
    <!-- bootstrap是基于jQuery-->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <script src="bootstrap-3.3.7-dist/js/bootstrap.min.js"></script>
   </body>
  </html>

4.2号横条，也就是row容器的定义,margin-left和margin-right都是-15px，组合row和列后，形成3号横条的效果，也就是左右宽度用满的效果。

//源码
.row {
margin-right: -15px;
margin-left: -15px;
}

有row，则会没边距

 <!DOCTYPE html>
  <html lang="en">
   <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- Bootstrap从3.0版本开始全面支持移动平台，贯彻移动先行宗旨 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <title>Bootstrap 101 Template</title>

    <!-- Bootstrap -->
    <link href="bootstrap-3.3.7-dist/css/bootstrap.min.css" rel="stylesheet">

   </head>
   <body>
    <div class="container" style="border:1px solid black">
      <div class="row">
        <div class="col-lg-1" style="border:1px solid black">col-lg-1</div>
        <div class="col-lg-1" style="border:1px solid black">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1">col-lg-1</div>
        <div class="col-lg-1" style="border:1px solid black">col-lg-1</div>
      </div>
    </div>
    <!-- bootstrap是基于jQuery-->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
    <script src="bootstrap-3.3.7-dist/js/bootstrap.min.js"></script>
   </body>
  </html>

1.1.2 基本用法

1.列组合

<div class="container" style="border:1px solid black">
  <div class="row">
    <div class="col-lg-8" style="border:1px solid black">col-lg-8</div>
    <div class="col-lg-4" style="border:1px solid black">col-lg-4</div>
  </div>
  <div class="row">
    <div class="col-lg-6" style="border:1px solid black">col-lg-6</div>
    <div class="col-lg-6" style="border:1px solid black">col-lg-6</div>
  </div>
</div>

实现很简单，就是涉及了两个CSS特性：左浮动和宽度百分比

//源码
@media (min-width: 1200px) {
 .col-lg-1, .col-lg-2, .col-lg-3, .col-lg-4, .col-lg-5, .col-lg-6, .col-lg-7, .col-lg-8, .col-lg-9, .col-lg-10, .col-lg-11, .col-lg-12 {
  float: left;
 }
 .col-lg-12 {
  width: 100%;
 }
 .col-lg-11 {
  width: 91.66666667%;
 }
 .col-lg-10 {
  width: 83.33333333%;
 }
 .col-lg-9 {
  width: 75%;
 }
 .col-lg-8 {
  width: 66.66666667%;
 }
 .col-lg-7 {
  width: 58.33333333%;
 }
 .col-lg-6 {
  width: 50%;
 }
 .col-lg-5 {
  width: 41.66666667%;
 }
 .col-lg-4 {
  width: 33.33333333%;
 }
 .col-lg-3 {
  width: 25%;
 }
 .col-lg-2 {
  width: 16.66666667%;
 }
 .col-lg-1 {
  width: 8.33333333%;
 }
}

2.列偏移

我们不想让相邻的列挨在一起，则利用栅格系统的列偏移.col-xs(sm,md,lg)-offset-* 功能来实现，不必再定义margin

<div class="row">
  <div class="col-lg-8 col-lg-offset-2" style="border:1px solid black">col-lg-8 col-lg-offset-2</div>
  <div class="col-lg-2 col-lg-offset-2" style="border:1px solid black">col-lg-2 col-lg-offset-2</div>
</div>

//源码
.col-lg-offset-12 {
 margin-left: 100%;
}
.col-lg-offset-11 {
 margin-left: 91.66666667%;
}
.col-lg-offset-10 {
 margin-left: 83.33333333%;
}
.col-lg-offset-9 {
 margin-left: 75%;
}
.col-lg-offset-8 {
 margin-left: 66.66666667%;
}
.col-lg-offset-7 {
 margin-left: 58.33333333%;
}
.col-lg-offset-6 {
 margin-left: 50%;
}
.col-lg-offset-5 {
 margin-left: 41.66666667%;
}
.col-lg-offset-4 {
 margin-left: 33.33333333%;
}
.col-lg-offset-3 {
 margin-left: 25%;
}
.col-lg-offset-2 {
 margin-left: 16.66666667%;
}
.col-lg-offset-1 {
 margin-left: 8.33333333%;
}
.col-lg-offset-0 {
 margin-left: 0;
}

3.列嵌套

栅格系统也支持列嵌套，也就是一个列中可以在声明一个或者多个行.内部嵌套的row宽度是100%，就是当前外部列的宽度

<div class="row">
  <div class="col-lg-8" style="border:1px solid black">col-lg-8</div>
  <div class="col-lg-4" style="border:1px solid black">
    <div class="row">
      <div class="col-lg-6">col-lg-6</div>
      <div class="col-lg-6">col-lg-6</div>
    </div>
  </div>
</div>

4.列排序

列排序就是改变列的方向，也就是改变左右浮动，并且设置浮动的距离。可以通过.col-xs(sm,md,lg)-pull(push)-*
所有列设置的都是左浮动，通过设置left和right来实现定位显示。push则设置left，pull则设置right

其实只是利用了float，left，right三个属性就实现了这种效果

//源码
.col-lg-pull-12 {
 right: 100%;
}
.col-lg-pull-11 {
 right: 91.66666667%;
}
.col-lg-pull-10 {
 right: 83.33333333%;
}
.col-lg-pull-9 {
 right: 75%;
}
.col-lg-pull-8 {
 right: 66.66666667%;
}
.col-lg-pull-7 {
 right: 58.33333333%;
}
.col-lg-pull-6 {
 right: 50%;
}
.col-lg-pull-5 {
 right: 41.66666667%;
}
.col-lg-pull-4 {
 right: 33.33333333%;
}
.col-lg-pull-3 {
 right: 25%;
}
.col-lg-pull-2 {
 right: 16.66666667%;
}
.col-lg-pull-1 {
 right: 8.33333333%;
}
.col-lg-pull-0 {
 right: auto;
}
.col-lg-push-12 {
 left: 100%;
}
.col-lg-push-11 {
 left: 91.66666667%;
}
.col-lg-push-10 {
 left: 83.33333333%;
}
.col-lg-push-9 {
 left: 75%;
}
.col-lg-push-8 {
 left: 66.66666667%;
}
.col-lg-push-7 {
 left: 58.33333333%;
}
.col-lg-push-6 {
 left: 50%;
}
.col-lg-push-5 {
 left: 41.66666667%;
}
.col-lg-push-4 {
 left: 33.33333333%;
}
.col-lg-push-3 {
 left: 25%;
}
.col-lg-push-2 {
 left: 16.66666667%;
}
.col-lg-push-1 {
 left: 8.33333333%;
}
.col-lg-push-0 {
 left: auto;
}

1.1.3 响应式栅格

已知col-xs-* col-sm-* col-md-* col-lg-*

1.跨设备组合定义
一种样式（比如col-md-9）在其定义的尺寸范围以外是不起作用的，比如，在小型或者大型屏幕上，所有带有md的样式都不会生效。我们可以在一个元素上应用不同的样式，以适配不同尺寸的屏幕。

<div class="container" style="border:1px solid black">
  <div class="row">
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div1 col-xs-6 col-sm-3 qwerwrgwefhsdgfsdfg</div>
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div2 col-xs-6 col-sm-3</div>
    <div class="clearfix visible-xs"></div>
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div3 col-xs-6 col-sm-3</div>
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div4 col-xs-6 col-sm-3</div>
  </div>
</div>

如图，由于div3换行时，但div1过高，则div3就右边紧挨着显示了。
所以需要利用clearfix样式清除浮动，但前提是在超小型屏幕上才显示(用visible-xs控制)

<div class="container" style="border:1px solid black">
  <div class="row">
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div1 col-xs-6 col-sm-3 qwerwrgwefhsdgfsdfg</div>
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div2 col-xs-6 col-sm-3</div>
    <div class="clearfix visible-xs"></div>
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div3 col-xs-6 col-sm-3</div>
    <div class="col-xs-6 col-sm-3" style="border:1px solid black"> div4 col-xs-6 col-sm-3</div>
  </div>
</div>

//源代码
.clearfix:before,
.clearfix:after,
.dl-horizontal dd:before,
.dl-horizontal dd:after,
.container:before,
.container:after,
.container-fluid:before,
.container-fluid:after,
.row:before,
.row:after,
.form-horizontal .form-group:before,
.form-horizontal .form-group:after,
.btn-toolbar:before,
.btn-toolbar:after,
.btn-group-vertical > .btn-group:before,
.btn-group-vertical > .btn-group:after,
.nav:before,
.nav:after,
.navbar:before,
.navbar:after,
.navbar-header:before,
.navbar-header:after,
.navbar-collapse:before,
.navbar-collapse:after,
.pager:before,
.pager:after,
.panel-body:before,
.panel-body:after,
.modal-header:before,
.modal-header:after,
.modal-footer:before,
.modal-footer:after {
 display: table;
 content: " ";
}
.clearfix:after,
.dl-horizontal dd:after,
.container:after,
.container-fluid:after,
.row:after,
.form-horizontal .form-group:after,
.btn-toolbar:after,
.btn-group-vertical > .btn-group:after,
.nav:after,
.navbar:after,
.navbar-header:after,
.navbar-collapse:after,
.pager:after,
.panel-body:after,
.modal-header:after,
.modal-footer:after {
 clear: both;
}
//源代码
@media (max-width: 767px) {
 .visible-xs {
  display: block !important;
 }
 table.visible-xs {
  display: table !important;
 }
 tr.visible-xs {
  display: table-row !important;
 }
 th.visible-xs,
 td.visible-xs {
  display: table-cell !important;
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。