我花了最后一天的时间试图弄清楚为什么导航栏内的下拉菜单在视口(viewport)更改时不起作用。
如果您通过手机(或开发人员工具)查看该通用示例并将方向旋转为横向，您将看到下拉列表中的链接无法访问。
我试图通过 overflow: scroll!important 添加 scroll 到 .dropdown 但没有成功。我也尝试将它定位在固定位置的顶部，但它没有用。
我想要的结果是，如果菜单在 View 上展开，您可以滚动屏幕(甚至下拉菜单本身)以查看其他链接。
请注意，当我从导航中删除类“fixed-top”时，一切都按预期工作，所以我猜这与此有关。
代码:
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
</head>
<body style="padding-top: 70px;">
<nav class="navbar navbar-expand-lg navbar-light bg-light fixed-top">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<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>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
</div>
</li>
</ul>
</div>
</nav>
<main>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
</main>
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>
</body>
</html>
最佳答案
var fixed = document.getElementById('fixed');
fixed.addEventListener('touchmove', function(e) {
e.preventDefault();
}, false);.dropdown-menu {
max-height: 70vh;
overflow-y: auto;
}
@media (max-width: 990px) {
.navbar.fixed-top {
overflow-y: auto;
max-height: 100vh;
}
}<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.5/popper.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/js/bootstrap.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet" />
<nav id="#fixed" class="navbar navbar-expand-lg navbar-light bg-light fixed-top">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Link</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<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>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
</div>
</li>
</ul>
</div>
</nav>
<main>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
<p>Example</p>
</main>使用 css 设置导航栏的最大高度:
@media (max-width: 990px){
.navbar.fixed-top{
overflow-y: auto;
max-height: 100vh;
}
}
关于css - 导航栏固定顶部内的 Bootstrap 4 下拉问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/53215905/