Bootstrap 4更改列在移动设备上的位置

Question

我有此代码：

<nav class="navbar navbar-toggleable-md navbar-light bg-faded">
  <button class="navbar-toggler navbar-toggler-right" 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>
  <a class="navbar-brand" href="#">Navbar</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>
    <form class="form-inline my-2 my-lg-0">
      <input class="form-control mr-sm-2" type="text" placeholder="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
    </form>
  </div>
</nav>

在移动设备上，我需要在第一个位置上显示表单搜索（之后：navbar-brand）。我该怎么办？我需要使用网格吗？

Answer 1

这是最新的Bootstrap 4.2的工作方式。您可以使用order-类对flexbox子项重新排序。将navbar-nav和form包装在flexbox容器（d-flex）中。这将使您能够响应地更改位置。例如，order-first order-md-last表示在md或更高版本上排在最后，而在md小于md上排在第一 ...

<nav class="navbar navbar-expand-md navbar-light bg-light">
    <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>
    <a class="navbar-brand" href="#">Navbar</a>
    <div class="collapse navbar-collapse" id="navbarSupportedContent">
        <div class="d-flex flex-column flex-md-row w-100 align-items-center">
            <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>
            <form class="form-inline flex-nowrap my-2 my-lg-0 order-first order-md-last">
                <input class="form-control mr-2" type="text" placeholder="Search">
                <button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
            </form>
        </div>
    </div>
</nav>