我是 css 和引导程序的新手,不知道如何解决这个问题。欢迎任何帮助。
我的代码有两个问题。
1(当我在小屏幕(移动(中单击"欢迎,用户"菜单时,下拉菜单在导航栏内打开,扭曲栏并更改其高度。我希望它的行为方式与在较大屏幕(例如台式机(上的行为方式相同。当我单击时,我希望它打开菜单项而不更改导航栏,在导航栏前面但不在里面。
2(另一个问题:即使在较大的屏幕上,我也无法完全看到菜单项。项目的某些文本隐藏在屏幕边缘。我希望菜单完全显示在屏幕上,无论是桌面还是移动设备。
为了清楚起见,我录制了一个非常小的视频来演示这个问题: https://puu.sh/Bq34w/ac56908be0.mp4
完整代码: https://jsfiddle.net/fredslz/0v7qwjdm/12/
<!doctype html>
<html lang="en">
<body class="text-center">
<nav class="navbar navbar-expand-md navbar-light fixed-top" style="background-color: #FFFFFF;">
<button class="navbar-toggler navbar-nav mr-auto" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<a class="navbar-brand mx-auto" href="#">My Brand</a>
<ul class="nav navbar-nav ml-md--auto">
<li class="dropdown">
<a href="#" class="nav-link dropdown-toggle" id="navbarDropdown" data-toggle="dropdown" aria-expanded="false">
Welcome, User <b class="caret"></b>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
</nav>
</body>
</html>
和 CSS:
.navbar {
-webkit-box-shadow: 0 8px 6px -6px #999;
-moz-box-shadow: 0 8px 6px -6px #999;
box-shadow: 0 8px 6px -6px #999;
}
如果您希望菜单项正确对齐,则需要在下拉列表中使用dropdown-menu-right
。
不清楚的是为什么使用切换器,因为您没有任何可折叠的菜单项(navbar-collapse
(。只需删除切换器并使用navbar-expand
,导航栏就不会在移动视图中折叠。
<nav class="navbar navbar-expand navbar-light fixed-top" style="background-color: #FFFFFF;">
<a class="navbar-brand mx-auto" href="#">My Brand</a>
<ul class="nav navbar-nav">
<li class="dropdown">
<a href="#" class="nav-link dropdown-toggle" id="navbarDropdown" data-toggle="dropdown" aria-expanded="false">
Welcome, User <b class="caret"></b>
</a>
<div class="dropdown-menu dropdown-menu-right">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
</nav>
https://www.codeply.com/go/j1HZLEdyrC
下拉列表将始终在移动折叠的导航栏中打开,这是设计使然。如果确实要保留移动切换器,并打算添加可折叠项目,则可以使用dropdown-menu
上的position-absolute
来覆盖默认行为。
<nav class="navbar navbar-expand-md navbar-light" style="background-color: #FFFFFF;">
<button class="navbar-toggler navbar-nav mr-auto" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<a class="navbar-brand mx-auto" href="#">My Brand</a>
<ul class="nav navbar-nav">
<li class="dropdown">
<a href="#" class="nav-link dropdown-toggle" id="navbarDropdown" data-toggle="dropdown" aria-expanded="false">
Welcome, User <b class="caret"></b>
</a>
<div class="dropdown-menu dropdown-menu-right position-absolute" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
</nav>
两个选项的演示:https://www.codeply.com/go/j1HZLEdyrC
相关: 引导 4 导航栏下拉菜单项右侧
对于移动下拉列表的问题,您也可以使用它将其绝对定位在移动视图中:
.navbar-nav .dropdown-menu {
position: absolute;
}
对于下拉列表的对齐方式,只需将类dropdown-menu-right
添加到您的dropdown-menu
。
请参阅下面的演示(我已经给出了!important
来处理代码片段中的级联顺序(并在此处工作小提琴:
.navbar {
-webkit-box-shadow: 0 8px 6px -6px #999;
-moz-box-shadow: 0 8px 6px -6px #999;
box-shadow: 0 8px 6px -6px #999;
/* the rest of your styling */
}
.navbar-nav .dropdown-menu {
position: absolute !important;
}
<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js"></script>
<link rel="stylesheet" type="text/css" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css">
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"></script>
<script type="text/javascript" src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>
<nav class="navbar navbar-expand-md navbar-light fixed-top" style="background-color: #FFFFFF;">
<button class="navbar-toggler navbar-nav mr-auto" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<a class="navbar-brand mx-auto" href="#">My Brand</a>
<ul class="nav navbar-nav ml-md--auto">
<li class="dropdown">
<a href="#" class="nav-link dropdown-toggle" id="navbarDropdown" data-toggle="dropdown" aria-expanded="false">
Welcome, User <b class="caret"></b>
</a>
<div class="dropdown-menu dropdown-menu-right" aria-labelledby="navbarDropdown">
<!-- ADDED CLASS -->
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</li>
</ul>
</nav>