Bootstrap 4导航栏不显示导航栏项

本文介绍了Bootstrap 4导航栏不显示导航栏项的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

导航栏显示我的品牌，但不显示菜单项. Bootstrap 4依存关系的顺序正确(Bootstrap 4 CSS-> Jquery-> Popper-> Bootstrap JS).<head>中引用的元视点.

Navbar is showing my branding, but not showing menu items. Bootstrap 4 dependencies are in right order (Bootstrap 4 CSS -> Jquery -> Popper -> Bootstrap JS).Meta viewpoint referenced in <head>.

HTML:

  <nav class="navbar navbar-light bg-faded">
    <a class="navbar-brand" onclick="goBack()">
      <img src="icon.jpg" width="30" height="30" class="d-inline-block align-top" alt="">
      Back to Course
    </a>
    <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">
          <a class="nav-link disabled" href="#">Disabled</a>
        </li>
      </ul>
    </div>
  </nav>

CSS:

@font-face {
    font-family: Helvetica;
    src: url(HelveticaNeue BlackCond.ttf);
}

@media (min-width: 992px) {
    .navbar-nav li a { line-height: 80px; }
}

@media (max-width: 991px) {
    .navbar-brand { float: none; }
}

.navbar-brand {
  font-family: 'Helvetica';
  font-weight: 500;
}

.container {
  padding-top: 2em;
}

推荐答案

这是因为代码中缺少navbar-expand-*类.

That's because the navbar-expand-* class is missing in your code.

我在下面的代码片段中添加了navbar-expand-md.此类在中等(md)或更大的屏幕上展开导航栏(从默认的折叠状态开始).

I've added navbar-expand-md in the code snippet below. This class expands the navbar (from the default collapsed state) on screens that are medium (md) or larger.

如果将其更改为navbar-expand-lg，则会从大屏幕(lg)等开始进行扩展.

If you change that to navbar-expand-lg, the expansion will happen form large (lg) screens onwards etc.

如果您想永久地扩展导航栏项，即在所有屏幕尺寸上永久扩展，请使用navbar-expand类.

And if you want your navbar items to be expanded permanently i.e. on all screen sizes, use the navbar-expand class.

您还需要 toggler ，以便在折叠导航栏时打开和关闭导航栏项目.您的代码中目前也缺少该切换器.

You also need a toggler in order to open and close the navbar items when the navbar is collapsed. That toggler is currently missing in your code as well.

点击下面的运行代码段"，然后展开到整页进行测试:

Click "run code snippet" below and expand to full page for testing:

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">

<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>

<nav class="navbar navbar-expand-md navbar-light bg-faded">
    <a class="navbar-brand" onclick="goBack()">
        <img src="https://placehold.it/30" width="30" height="30" class="d-inline-block align-top" alt="">
        Back to Course
    </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">
                <a class="nav-link disabled" href="#">Disabled</a>
            </li>
        </ul>
    </div>
</nav>

这篇关于Bootstrap 4导航栏不显示导航栏项的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！