折叠时导航栏错误 |引导程序 4答案

【问题标题】：navbar error when collapsed | Bootstrap 4折叠时导航栏错误 |引导程序 4
【发布时间】：2018-02-21 10:19:52
【问题描述】：

导航栏切换按钮位于网页和移动模式的右上角，但是当导航栏在移动模式下折叠时出现问题（最后一张图片）。

我知道这是因为我的代码的行序，但我不知道如何修复它。

网页模式：

移动模式：

折叠移动模式：

<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
    <a class="navbar-brand" href="#">EVENT</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 dropdown">
          <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
            <?=$_SESSION['name'];?>
          </a>
          <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
            <a class="dropdown-item" href="#">Action</a>
            <a class="dropdown-item" href="#">Another action</a>
            <a class="dropdown-item" href="#">Something else here</a>
            <div class="dropdown-divider"></div>
            <a class="dropdown-item" href="login/logout.php">Logout</a>
          </div>
        </li>
      </ul>
    </div>
    <div class="nav-item" style="float:top">
      <input class="btn btn-danger" type="submit" value="Create">
      <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>
  </nav>

【问题讨论】：

标签： mobile alignment bootstrap-4 navbar

【解决方案1】：

解决这个问题的一种方法是：

将红色按钮的代码放在 HTML 中导航栏品牌项之后
给它ml-auto order-lg-last 的类。前者表示“margin-left:auto”，后者将在大屏幕 (lg) 或更大的屏幕上重新排序该按钮并将其放在最后一个位置。 ml-auto 然后实际上将其推到右侧。
给切换器（应该位于 HTML 中的红色按钮之后）ml-2 类以在它和红色按钮之间留出一点空间。

点击下方“运行代码sn-p”按钮，展开至整页：

<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-lg navbar-dark bg-dark">
    <a class="navbar-brand" href="#">EVENT</a>

    <div class="nav-item ml-auto order-lg-last">
        <input class="btn btn-danger" type="submit" value="Create">
    </div>

    <button class="navbar-toggler ml-2" 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 dropdown">
                <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                    <?=$_SESSION['name'];?>
                </a>
                <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                    <a class="dropdown-item" href="#">Action</a>
                    <a class="dropdown-item" href="#">Another action</a>
                    <a class="dropdown-item" href="#">Something else here</a>
                    <div class="dropdown-divider"></div>
                    <a class="dropdown-item" href="login/logout.php">Logout</a>
                </div>
            </li>
        </ul>
    </div>
</nav>

【讨论】：