自学教程Bootstrap 4 中允许我们将按钮放在同一行上。
可以在 <div> 元素上添加 .btn-group 类来创建按钮组。
<div class="btn-group">
<button type="button" class="btn btn-primary">Apple</button>
<button type="button" class="btn btn-primary">Samsung</button>
<button type="button" class="btn btn-primary">Sony</button>
</div>提示: 我们可以使用 .btn-group-lg|sm 类来设置按钮组的大小。
<div class="btn-group btn-group-lg">
<button type="button" class="btn btn-primary">Apple</button>
<button type="button" class="btn btn-primary">Samsung</button>
<button type="button" class="btn btn-primary">Sony</button>
</div>垂直按钮组
可以使用 .btn-group-vertical 类来创建垂直的按钮组：
<div class="btn-group-vertical">
<button type="button" class="btn btn-primary">Apple</button>
<button type="button" class="btn btn-primary">Samsung</button>
<button type="button" class="btn btn-primary">Sony</button>
</div>内嵌按钮组及下拉菜单
我们可以在按钮组内设置下拉菜单：
<div class="btn-group">
<button type="button" class="btn btn-primary">Apple</button>
<button type="button" class="btn btn-primary">Samsung</button>
<div class="btn-group">
<button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
Sony
</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Tablet</a>
<a class="dropdown-item" href="#">Smartphone</a>
</div>
</div>
</div>拆分按钮下拉菜单
<div class="btn-group">
<button type="button" class="btn btn-primary">Sony</button>
<button type="button" class="btn btn-primary dropdown-toggle dropdown-toggle-split" data-toggle="dropdown">
<span class="caret"></span>
</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Tablet</a>
<a class="dropdown-item" href="#">Smartphone</a>
</div>
</div>垂直按钮组及下拉菜单
<div class="btn-group-vertical">
<button type="button" class="btn btn-primary">Apple</button>
<button type="button" class="btn btn-primary">Samsung</button>
<div class="btn-group">
<button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
Sony
</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Tablet</a>
<a class="dropdown-item" href="#">Smartphone</a>
</div>
</div>
</div>多个按钮组
按钮组可以一个个并列显示在同一行上：
<div class="btn-group">
<button type="button" class="btn btn-primary">Apple</button>
<button type="button" class="btn btn-primary">Samsung</button>
<button type="button" class="btn btn-primary">Sony</button>
</div>
<div class="btn-group">
<button type="button" class="btn btn-primary">BMW</button>
<button type="button" class="btn btn-primary">Mercedes</button>
<button type="button" class="btn btn-primary">Volvo</button>
</div>