Bootstrap 4 导航栏菜单（移动）风格像 Bootstrap 3？

Question

Bootstrap 4 个例子

Bootstrap 3 个例子

如何像 Bootstrap 3 那样获得 Bootstrap 4 菜单？

此代码来自 bootstrap 4 http://v4-alpha.getbootstrap.com/examples/navbar/:

<div class="container">
      <nav class="navbar navbar-light bg-faded">
        <button class="navbar-toggler hidden-sm-up" type="button" data-toggle="collapse" data-target="#navbar-header" aria-controls="navbar-header">
          &#9776;
        </button>
        <div class="collapse navbar-toggleable-xs" id="navbar-header">
          <a class="navbar-brand" href="#">Navbar</a>
          <ul class="nav navbar-nav">
            <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="#">Features</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="#">Pricing</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="#">About</a>
            </li>
          </ul>
          <form class="form-inline pull-xs-right">
            <input class="form-control" type="text" placeholder="Search">
            <button class="btn btn-outline-success" type="submit">Search</button>
          </form>
        </div>
      </nav> <!-- /navbar -->
</div><!-- /container -->

Answer 1

您需要在 bootstrap 4 中添加一些 css 我想他们这样做是因为您可以切换不同大小的菜单，因此您需要将媒体查询添加到您想要的任何大小希望您的菜单打开于。像这样：

这是一个 fiddle，其中包含 bootstrap 4 导航栏的一些自定义样式 Bootstrap 4 Navbar Fiddle

@media(max-width:33.9em) {
  .navbar .collapse {max-height:250px;width:100%;overflow-y:auto;overflow-x:hidden;}
  .navbar .navbar-brand {float:none;display: inline-block;}
  .navbar .navbar-nav>.nav-item { float: none; margin-left: .1rem;}
  .navbar .navbar-nav {float:none !important;}
  .nav-item{width:100%;text-align:left;}
  .navbar .collapse .dropdown-menu {
    position: relative;
    float: none;
    background:none;
    border:none;
  }
}

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