bootstrap之button样式

一、前言

现在开始介绍bootstrap的button模块样式，包括buttons.less、button-groups.less。

二、源码

1、buttons.less

1.1、buttons.less源码

 // // Buttons(按钮) // -------------------------------------------------- // Base styles(基础样式) // -------------------------------------------------- .btn {   display: inline-block;   margin-bottom: 0; // For input.btn   font-weight: @btn-font-weight;   text-align: center;   vertical-align: middle;   touch-action: manipulation;   cursor: pointer;   background-image: none; // Reset unusual Firefox-on-Android default style; see https://github.com/necolas/normalize.css/issues/214   border: 1px solid transparent;   white-space: nowrap;   .button-size(@padding-base-vertical; @padding-base-horizontal; @font-size-base; @line-height-base; @btn-border-radius-base);   .user-select(none);   &,   &:active,   &.active {     &:focus,     &.focus {       .tab-focus();     }   }   &:hover,   &:focus,   &.focus {     color: @btn-default-color;     text-decoration: none;   }   &:active,   &.active {     outline: 0;     background-image: none;     .box-shadow(inset 0 3px 5px rgba(0,0,0,.125));   }   &.disabled,   &[disabled],   fieldset[disabled] & {     cursor: @cursor-disabled;     .opacity(.65);     .box-shadow(none);   }   a& {     &.disabled,     fieldset[disabled] & {       pointer-events: none; // Future-proof disabling of clicks on `<a>` elements     }   } } // Alternate buttons(交互式按钮) // -------------------------------------------------- .btn-default {   .button-variant(@btn-default-color; @btn-default-bg; @btn-default-border); } .btn-primary {   .button-variant(@btn-primary-color; @btn-primary-bg; @btn-primary-border); } // Success appears as green .btn-success {   .button-variant(@btn-success-color; @btn-success-bg; @btn-success-border); } // Info appears as blue-green .btn-info {   .button-variant(@btn-info-color; @btn-info-bg; @btn-info-border); } // Warning appears as orange .btn-warning {   .button-variant(@btn-warning-color; @btn-warning-bg; @btn-warning-border); } // Danger and error appear as red .btn-danger {   .button-variant(@btn-danger-color; @btn-danger-bg; @btn-danger-border); } // Link buttons(链接按钮) // ------------------------- // Make a button look and behave like a link .btn-link {   color: @link-color;   font-weight: normal;   border-radius: 0;   &,   &:active,   &.active,   &[disabled],   fieldset[disabled] & {     background-color: transparent;     .box-shadow(none);   }   &,   &:hover,   &:focus,   &:active {     border-color: transparent;   }   &:hover,   &:focus {     color: @link-hover-color;     text-decoration: @link-hover-decoration;     background-color: transparent;   }   &[disabled],   fieldset[disabled] & {     &:hover,     &:focus {       color: @btn-link-disabled-color;       text-decoration: none;     }   } } // Button Sizes(按钮大小) // -------------------------------------------------- .btn-lg {   // line-height: ensure even-numbered height of button next to large input   .button-size(@padding-large-vertical; @padding-large-horizontal; @font-size-large; @line-height-large; @btn-border-radius-large); } .btn-sm {   // line-height: ensure proper height of button next to small input   .button-size(@padding-small-vertical; @padding-small-horizontal; @font-size-small; @line-height-small; @btn-border-radius-small); } .btn-xs {   .button-size(@padding-xs-vertical; @padding-xs-horizontal; @font-size-small; @line-height-small; @btn-border-radius-small); } // Block button(块状按钮) // -------------------------------------------------- .btn-block {   display: block;   width: 100%; } // Vertically space out multiple block buttons .btn-block + .btn-block {   margin-top: 5px; } // Specificity overrides input[type="submit"], input[type="reset"], input[type="button"] {   &.btn-block {     width: 100%;   } }

1.2、buttons.less应用

 // 按钮动作 & 按钮大小 & 按钮状态 <!-- 标准的按钮 --> <button type="button" class="btn btn-default btn-lg active">默认大激活按钮</button> <!-- 提供额外的视觉效果，标识一组按钮中的原始动作 --> <button type="button" class="btn btn-primary disabled">原始默认大小禁用按钮</button> <!-- 表示一个成功的或积极的动作 --> <button type="button" class="btn btn-success btn-sm">成功小按钮</button> <!-- 信息警告消息的上下文按钮 --> <button type="button" class="btn btn-info btn-xs">信息特小按钮</button> <!-- 表示应谨慎采取的动作 --> <button type="button" class="btn btn-warning btn-lg btn-block">警告块级按钮</button> <!-- 表示一个危险的或潜在的负面动作 --> <button type="button" class="btn btn-danger">危险默认大小按钮</button> <!-- 并不强调是一个按钮，看起来像一个链接，但同时保持按钮的行为 --> <button type="button" class="btn btn-link">链接默认大小按钮</button>

2、button-groups.less

2.1、button-groups.less源码

 // // Button groups(按钮组) // -------------------------------------------------- // Make the div behave like a button(按钮组) .btn-group, .btn-group-vertical {   position: relative;   display: inline-block;   vertical-align: middle; // match .btn alignment given font-size hack above   > .btn {     position: relative;     float: left;     // Bring the "active" button to the front     &:hover,     &:focus,     &:active,     &.active {       z-index: 2;     }   } } // Prevent double borders when buttons are next to each other(去除按钮组间的边框) .btn-group {   .btn + .btn,   .btn + .btn-group,   .btn-group + .btn,   .btn-group + .btn-group {     margin-left: -1px;   } } // Optional: Group multiple button groups together for a toolbar(工具栏，按钮分组的父容器) .btn-toolbar {   margin-left: -5px; // Offset the first child's margin   &:extend(.clearfix all);   .btn,   .btn-group,   .input-group {     float: left;   }   > .btn,   > .btn-group,   > .input-group {     margin-left: 5px;   } } // 去除圆角，生成按钮组圆角效果 .btn-group > .btn:not(:first-child):not(:last-child):not(.dropdown-toggle) {   border-radius: 0; } // Set corners individual because sometimes a single button can be in a .btn-group and we need :first-child and :last-child to both match .btn-group > .btn:first-child {   margin-left: 0;   &:not(:last-child):not(.dropdown-toggle) {     .border-right-radius(0);   } } // Need .dropdown-toggle since :last-child doesn't apply, given that a .dropdown-menu is used immediately after it .btn-group > .btn:last-child:not(:first-child), .btn-group > .dropdown-toggle:not(:first-child) {   .border-left-radius(0); } // Custom edits for including btn-groups within btn-groups (useful for including dropdown buttons within a btn-group) .btn-group > .btn-group {   float: left; } .btn-group > .btn-group:not(:first-child):not(:last-child) > .btn {   border-radius: 0; } .btn-group > .btn-group:first-child:not(:last-child) {   > .btn:last-child,   > .dropdown-toggle {     .border-right-radius(0);   } } .btn-group > .btn-group:last-child:not(:first-child) > .btn:first-child {   .border-left-radius(0); } // On active and open, don't show outline .btn-group .dropdown-toggle:active, .btn-group.open .dropdown-toggle {   outline: 0; } // Sizing(按钮组大小设置) // // Remix the default button sizing classes into new ones for easier manipulation. .btn-group-xs > .btn { &:extend(.btn-xs); } .btn-group-sm > .btn { &:extend(.btn-sm); } .btn-group-lg > .btn { &:extend(.btn-lg); } // Split button dropdowns(嵌套分组) // ---------------------- // Give the line between buttons some depth .btn-group > .btn + .dropdown-toggle {   padding-left: 8px;   padding-right: 8px; } .btn-group > .btn-lg + .dropdown-toggle {   padding-left: 12px;   padding-right: 12px; } // The clickable button for toggling the menu // Remove the gradient and set the same inset shadow as the :active state .btn-group.open .dropdown-toggle {   .box-shadow(inset 0 3px 5px rgba(0,0,0,.125));   // Show no shadow for `.btn-link` since it has no other button styles.   &.btn-link {     .box-shadow(none);   } } // Reposition the caret .btn .caret {   margin-left: 0; } // Carets in other button sizes .btn-lg .caret {   border-width: @caret-width-large @caret-width-large 0;   border-bottom-width: 0; } // Upside down carets for .dropup .dropup .btn-lg .caret {   border-width: 0 @caret-width-large @caret-width-large; } // Vertical button groups(垂直按钮组) // ---------------------- .btn-group-vertical {   > .btn,   > .btn-group,   > .btn-group > .btn {     display: block;     float: none;     width: 100%;     max-width: 100%;   }   // Clear floats so dropdown menus can be properly placed   > .btn-group {     &:extend(.clearfix all);     > .btn {       float: none;     }   }   > .btn + .btn,   > .btn + .btn-group,   > .btn-group + .btn,   > .btn-group + .btn-group {     margin-top: -1px;     margin-left: 0;   } } .btn-group-vertical > .btn {   &:not(:first-child):not(:last-child) {     border-radius: 0;   }   &:first-child:not(:last-child) {     .border-top-radius(@btn-border-radius-base);     .border-bottom-radius(0);   }   &:last-child:not(:first-child) {     .border-top-radius(0);     .border-bottom-radius(@btn-border-radius-base);   } } .btn-group-vertical > .btn-group:not(:first-child):not(:last-child) > .btn {   border-radius: 0; } .btn-group-vertical > .btn-group:first-child:not(:last-child) {   > .btn:last-child,   > .dropdown-toggle {     .border-bottom-radius(0);   } } .btn-group-vertical > .btn-group:last-child:not(:first-child) > .btn:first-child {   .border-top-radius(0); } // Justified button groups(等分按钮) // ---------------------- .btn-group-justified {   display: table;   width: 100%;   table-layout: fixed;   border-collapse: separate;   > .btn,   > .btn-group {     float: none;     display: table-cell;     width: 1%;   }   > .btn-group .btn {     width: 100%;   }   > .btn-group .dropdown-menu {     left: auto;   } } // Checkbox and radio options // // In order to support the browser's form validation feedback, powered by the // `required` attribute, we have to "hide" the inputs via `clip`. We cannot use // `display: none;` or `visibility: hidden;` as that also hides the popover. // Simply visually hiding the inputs via `opacity` would leave them clickable in // certain cases which is prevented by using `clip` and `pointer-events`. // This way, we ensure a DOM element is visible to position the popover from. // // See https://github.com/twbs/bootstrap/pull/12794 and // https://github.com/twbs/bootstrap/pull/14559 for more information. [data-toggle="buttons"] {   > .btn,   > .btn-group > .btn {     input[type="radio"],     input[type="checkbox"] {       position: absolute;       clip: rect(0,0,0,0);       pointer-events: none;     }   } }

2.2、button-groups.less应用

 <!--btn-toolbar: 按钮工具栏--> <div class="btn-toolbar" role="toolbar">   <!--大按钮组-->   <div class="btn-group btn-group-lg">     <button type="button" class="btn btn-default">按钮 1</button>     <button type="button" class="btn btn-default">按钮 2</button>   </div>   <!--小按钮组-->   <div class="btn-group btn-group-sm">     <button type="button" class="btn btn-default">按钮 3</button>     <button type="button" class="btn btn-default">按钮 4</button>   </div>   <!--特小按钮组-->   <div class="btn-group btn-group-xs">     <button type="button" class="btn btn-default">按钮 5</button>     <button type="button" class="btn btn-default">按钮 6</button>   </div>   <!--垂直按钮组-->   <div class="btn-group-vertical">     <button type="button" class="btn btn-default">按钮 7</button>     <button type="button" class="btn btn-default">按钮 8</button>   </div>   <!--嵌套按钮组-->   <div class="btn-group">     <button type="button" class="btn btn-default">按钮 9</button>     <button type="button" class="btn btn-default">按钮 10</button>     <div class="btn-group">       <button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown">         下列         <span class="caret"></span>       </button>       <ul class="dropdown-menu">         <li><a href="#">下拉链接 1</a></li>         <li><a href="#">下拉链接 2</a></li>       </ul>     </div>   </div> </div>