这是我参与更文挑战的第23天,活动详情查看: 更文挑战css
《Bootstrap5零基础到精通》 俺老刘原创,争取天天更新一节。html
下拉菜单(Dropdowns)和表单里面的下拉列表(Select)具备不少外观上的类似性,但却有着本质的不一样,下拉列表使用的是Select表单,而下拉菜单(Dropdowns)使用的是div和css实现。bootstrap
下拉列表是可切换的上下文覆盖,用于显示连接列表等。它们与附带的Bootstrap 下拉JavaScript插件交互。它们是经过点击来切换的,而不是经过悬停来切换的;这是一个有意的设计决定,若是你须要悬停切换,能够经过js实现。浏览器
将下拉菜单的切换(按钮或连接)和下拉菜单包装在dropdown中就变成了下拉菜单。markdown
能够从a或button元素触发下拉列表,以更好地知足您的潜在需求。这里显示的示例在适当的地方使用语义ul元素,可是支持自定义标记。ide
任何单个.btn均可以变成一个下拉切换,并有一些标记更改。下面是如何将它们与button元素一块儿使用:工具
<!doctype html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="keywords" content="">
<meta name="description" content="">
<link href="../bootstrap5/bootstrap.min.css" rel="stylesheet">
<title>下拉菜单</title>
</head>
<body>
<div class="container">
<br><br><br>
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false">
button下拉菜单
</button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuButton1">
<li><a class="dropdown-item" href="#">子菜单1</a></li>
<li><a class="dropdown-item" href="#">子菜单2</a></li>
<li><a class="dropdown-item" href="#">子菜单3</a></li>
<li><hr class="dropdown-divider"></li>
<li><a class="dropdown-item" href="#">子菜单4</a></li>
</ul>
</div>
<br><br><br>
<div class="dropdown">
<a class="btn btn-secondary dropdown-toggle" href="#" role="button" id="dropdownMenuLink" data-bs-toggle="dropdown" aria-expanded="false">
a 连接下拉菜单
</a>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuLink">
<li><a class="dropdown-item" href="#">子菜单1</a></li>
<li><a class="dropdown-item" href="#">子菜单2</a></li>
<li><a class="dropdown-item" href="#">子菜单3</a></li>
<li><hr class="dropdown-divider"></li>
<li><a class="dropdown-item" href="#">子菜单4</a></li>
</ul>
</div>
</div>
<script src="../bootstrap5/bootstrap.bundle.min.js" ></script>
</body>
</html>
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两种菜单从外观和体验上看是没有任何区别的。oop
按钮组就是同一行中同时存在几个按钮,默认状况下,因为菜单默认是独占一行的,两个菜单靠在一块儿不美观,故上面的例子加了几个换行。post
按钮组的使用十分简单,直接把按钮的<div class="dropdown">
换成<div class="btn-group">
,并非把单个按钮放在一个按钮组容器中,这点必定要注意。学习
<div class="btn-group">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> button下拉菜单 </button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuButton1"> <li><a class="dropdown-item" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> <li><hr class="dropdown-divider"></li> <li><a class="dropdown-item" href="#">子菜单4</a></li> </ul> </div>
<div class="btn-group"> <a class="btn btn-secondary dropdown-toggle" href="#" role="button" id="dropdownMenuLink" data-bs-toggle="dropdown" aria-expanded="false"> a 连接下拉菜单 </a> <ul class="dropdown-menu" aria-labelledby="dropdownMenuLink"> <li><a class="dropdown-item" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> <li><hr class="dropdown-divider"></li> <li><a class="dropdown-item" href="#">子菜单4</a></li> </ul> </div> 复制代码
默认状况下,点击按钮任何区域,都会弹出下拉菜单,可是经过往添加dropdown-toggle-split以在下拉插入符号作适当间隔,这插入符号的两边水平padding减小了25%,并移除了为常规按钮下拉菜单添加的margin-left。这些额外的变化使插入符号集中在分割按钮中,并在主按钮旁边提供适当的空间。
分割按钮只能用于按钮组,只有点击按钮上的三角符号,下拉菜单才会弹出,点按钮其余地方都不在弹出。 下面代码第一个是普通按钮,第二个是分割按钮
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> 普通下拉菜单 </button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuButton1"> <li><a class="dropdown-item" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> </ul>
</div>
<br>
<div class="btn-group"> <button type="button" class="btn btn-secondary">分割下拉菜单</button> <button class="btn btn-secondary dropdown-toggle dropdown-toggle-split" type="button" data-bs-toggle="dropdown" aria-expanded="false"> <span class="visually-hidden">Toggle Dropdown</span> </button> <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton1"> <li><a class="dropdown-item" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> </ul> </div>
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将或者加到button按钮类中,就能够实现按钮大小的设置,虽然例子中用的是按钮组,但对单个按钮和分割按钮一样适用。 下面是三种按钮大小比较:
<div class="btn-group">
<button class="btn btn-sm btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> sm下拉菜单 </button>
</div>
<div class="btn-group"> <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> 下拉菜单 </button> </div>
<div class="btn-group"> <button class="btn btn-lg btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> lg下拉菜单 </button> </div>
<div class="btn-group"> <button class="btn btn-secondary btn-sm" type="button"> sm分割按钮 </button> <button type="button" class="btn btn-sm btn-secondary dropdown-toggle dropdown-toggle-split" data-bs-toggle="dropdown" aria-expanded="false"> <span class="visually-hidden">Toggle Dropdown</span> </button> </div>
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注意:后面通常状况下,为了节俭代码,对于不须要弹出选项的菜单都省略菜单部分。
下拉菜单的颜色与按钮的颜色彻底一致,如下是各类颜色的下拉菜单:
<div class="btn-group">
<button class="btn btn-primary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> primary </button>
</div>
<div class="btn-group"> <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> secondary </button> </div>
<div class="btn-group"> <button class="btn btn-success dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> success </button> </div>
<div class="btn-group"> <button class="btn btn-danger dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> danger </button> </div>
<div class="btn-group"> <button class="btn btn-warning dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> warning </button> </div>
<div class="btn-group"> <button class="btn btn-info dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> info </button> </div>
<div class="btn-group"> <button class="btn btn-light dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> light </button> </div>
<div class="btn-group"> <button class="btn btn-dark dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> dark </button> </div>
<div class="btn-group"> <button class="btn btn-link dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> link </button> </div>
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选择较暗的下拉菜单以匹配深色导航栏或自定义样式,方法是将dropdown-menu-dark
添加到现有的dropdown-menu
。不须要更改下拉项。
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton2" data-bs-toggle="dropdown" aria-expanded="false"> 深色下拉菜单 </button>
<ul class="dropdown-menu dropdown-menu-dark" aria-labelledby="dropdownMenuButton2"> <li><a class="dropdown-item active" href="#">Action选项1</a></li> <li><a class="dropdown-item" href="#">选项2</a></li> <li><a class="dropdown-item" href="#">选项3</a></li> <li><hr class="dropdown-divider"></li> <li><a class="dropdown-item" href="#">选项4</a></li> </ul> </div>
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<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
<div class="container-fluid"> <a class="navbar-brand" href="#">品牌</a> <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNavDarkDropdown" aria-controls="navbarNavDarkDropdown" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> <div class="collapse navbar-collapse" id="navbarNavDarkDropdown"> <ul class="navbar-nav"> <li class="nav-item dropdown"> <a class="nav-link dropdown-toggle" href="#" id="navbarDarkDropdownMenuLink" role="button" data-bs-toggle="dropdown" aria-expanded="false"> 深色下拉菜单 </a> <ul class="dropdown-menu dropdown-menu-dark" aria-labelledby="dropdownMenuButton2"> <li><a class="dropdown-item active" href="#">Action选项1</a></li> <li><a class="dropdown-item" href="#">选项2</a></li> <li><a class="dropdown-item" href="#">选项3</a></li> <li><hr class="dropdown-divider"></li> <li><a class="dropdown-item" href="#">选项4</a></li> </ul> </li> </ul> </div> </div> </nav>
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下拉菜单默认的选项默认是向下弹出的,经过在下拉菜单的容器中添加dropup、dropstart、dropend
,能够分别设置向上、向左、向右弹出。
这几个类的用法很简单,直接加在容器上便可。须要注意的是,这几个方向设置都是在空间足够状况下说的,若是向上弹出,可是上面空间不够,则会自动改成向下弹出。向左、向右也是如此
<div class="text-center">
<br><br><br><br><br><br>
<div class="dropdown dropup"> <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> 向上 </button> <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton1"> <li><a class="dropdown-item active" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> </ul> </div> <br><br><br>
<div class="dropdown dropstart"> <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton2" data-bs-toggle="dropdown" aria-expanded="false"> 向左 </button> <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton2"> <li><a class="dropdown-item active" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> </ul> </div>
<br><br><br>
<div class="dropdown dropend"> <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton3" data-bs-toggle="dropdown" aria-expanded="false"> 向右 </button> <ul class="dropdown-menu" aria-labelledby="dropdownMenuButton3"> <li><a class="dropdown-item active" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> </ul> </div>
</div>
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在过去下拉菜单内容必须是个连接,但Bootstrap5再也不是这样。如今您能够选择在下拉菜单中使用button元素,而不是仅使用a。
也可使用dropdown-item文本建立非交互式下拉项。您能够随意使用自定义CSS或文本工具进一步设计样式。默认状况下,使用连接和按钮选项,鼠标悬停在选项上会有阴影,文本选项五阴影效果。
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton2" data-bs-toggle="dropdown" aria-expanded="false"> 其余选项下拉菜单 </button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuButton2"> <li><button class="dropdown-item" type="button">按钮选项1</button></li> <li><button class="dropdown-item" type="button">按钮选项2</button></li> <li><span class="dropdown-item-text">文本选项</span></li> </ul>
</div>
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将active添加到下拉列表中的项以将其设置为活动样式。 将disabled添加到下拉列表中的项以将其样式设置为禁用。
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton2" data-bs-toggle="dropdown" aria-expanded="false"> 下拉菜单 </button>
<ul class="dropdown-menu" aria-labelledby="dropdownMenuButton2"> <li><a class="dropdown-item active" href="#">激活选项</a></li> <li><a class="dropdown-item" href="#">普通选项</a></li> <li><a class="dropdown-item disabled" href="#">禁用选项</a></li> </ul>
</div>
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默认状况下,下拉菜单自动定位在距父菜单顶部100%的位置,并沿父菜单的左侧。你能够将dropdown-menu-end
添加到dropdown-menu
以右对齐下拉菜单。
<div class="btn-group">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton1" data-bs-toggle="dropdown" aria-expanded="false"> 菜单项右对齐 过短了看不出 </button>
<ul class="dropdown-menu dropdown-menu-end" aria-labelledby="dropdownMenuButton1"> <li><a class="dropdown-item" href="#">子菜单1</a></li> <li><a class="dropdown-item" href="#">子菜单2</a></li> <li><a class="dropdown-item" href="#">子菜单3</a></li> <li><hr class="dropdown-divider"></li> <li><a class="dropdown-item" href="#">子菜单4</a></li> </ul> </div>
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若是要使用响应式对齐,请经过在button添加 data-bs-display="static"属性禁用动态定位,并使用响应式变量类。 在dropdown-menu添加dropdown-menu{-sm|-md|-lg|-xl|-xxl}-end。
<!doctype html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="keywords" content="">
<meta name="description" content="">
<link href="../bootstrap5/bootstrap.min.css" rel="stylesheet">
<title>下拉菜单</title>
</head>
<body>
<div class="container">
<br><br><br>
<div class="btn-group">
<button class="btn btn-secondary dropdown-toggle" type="button" data-bs-toggle="dropdown" data-bs-display="static" aria-expanded="false">
菜单项响应式右对齐,改变浏览器大小观看
</button>
<ul class="dropdown-menu dropdown-menu-lg-end" aria-labelledby="dropdownMenuButton1">
<li><a class="dropdown-item" href="#">子菜单1</a></li>
<li><a class="dropdown-item" href="#">子菜单2</a></li>
<li><a class="dropdown-item" href="#">子菜单3</a></li>
<li><hr class="dropdown-divider"></li>
<li><a class="dropdown-item" href="#">子菜单4</a></li>
</ul>
</div>
</div>
<script src="../bootstrap5/bootstrap.bundle.min.js" ></script>
</body>
</html>
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这个在lg断点前左对齐,断点后右对齐,比较简单就不演示了,提供完整代码,有兴趣的试一下。
将表单放入下拉菜单中,或将其放入下拉菜单中,而后使用边距或填充实用程序为其提供所需的负空间。
<div class="btn-group">
<button class="btn btn-secondary dropdown-toggle" type="button" data-bs-toggle="dropdown" aria-expanded="false"> 菜单项包含登陆表单 </button>
<div class="dropdown-menu">
<form class="px-4 py-3">
<div class="mb-3">
<label for="exampleDropdownFormEmail1" class="form-label">电子邮箱</label>
<input type="email" class="form-control" id="exampleDropdownFormEmail1" placeholder="email@example.com">
</div>
<div class="mb-3">
<label for="exampleDropdownFormPassword1" class="form-label">密码</label>
<input type="password" class="form-control" id="exampleDropdownFormPassword1" placeholder="Password">
</div>
<div class="mb-3">
<div class="form-check">
<input type="checkbox" class="form-check-input" id="dropdownCheck">
<label class="form-check-label" for="dropdownCheck">
记住状态
</label>
</div>
</div>
<button type="submit" class="btn btn-primary">登陆</button>
</form>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">还没帐户,点此注册</a>
<a class="dropdown-item" href="#">忘记密码</a>
</div>
</div>
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限于篇幅,本文对下拉菜单作了简要介绍,通常状况下足够日常的使用了,若是你须要更详细的了解下拉菜单用法,请参考Bootstrap中文文档 >组件 >下拉菜单相关章节。
今天的课程就到这里,请关注我,及时学习 俺老刘原创的《Bootstrap5零基础到精通》第24节 Bootstrap5分页导航Pagination组件用法,从字面也能够看出,按钮组就是多个按钮的组合。
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