使用 Bootstrap 4 将搜索栏移动到中等屏幕的第二行

Question

此导航栏使用 Bootstrap 4。对于中型屏幕（768 像素到 991 像素），我希望将搜索栏和按钮移动到第二行，因为它在大屏幕及以上屏幕上。目前，在中等屏幕上，搜索栏会紧挨着其他导航链接：

它在大/超大屏幕上的显示效果：

根据第一个答案建议更新代码：

<nav class="navbar navbar-expand-md navbar-fixed-top navbar-dark bg-navbar">
    <div class="container">
        <a class="navbar-brand" href="/" style="align-children: middle">
        <span class="" aria-hidden="true"></span>
            Example
        </a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#site-nav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="sr-only">Toggle navigation</span>
            <span class="navbar-toggler-icon"></span>
        </button>

        <div class="collapse navbar-collapse ml-auto" id="site-nav">
            <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="/agencies/">Agencies</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/meetings/">Meetings</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/agenda/">Agenda</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/documents/">Documents</a>
                </li>
            </ul>
            <form class="form-inline mt-3 mb-3" role="search" action="/search/" method="post">
                <div class="btn-group">
                    <input type="text" name="request" class="form-control" placeholder="Search Documents">
                    <button type="submit" class="btn search-button">Search</button>
                </div>
            </form>
        </div>
    </div>
</nav>

Answer 1

您可以使用响应式 flexbox 方向工具。例如，flex-column flex-xl-row 上的 navbar-collapse。

<nav class="navbar navbar-expand-md fixed-top navbar-dark bg-dark">
    <div class="container">
        <a class="navbar-brand" href="/" style="align-children: middle">
        <span class="" aria-hidden="true"></span>
            Example
        </a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#site-nav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="sr-only">Toggle navigation</span>
            <span class="navbar-toggler-icon"></span>
        </button>

        <div class="collapse navbar-collapse ml-auto align-items-start align-items-xl-center flex-column flex-xl-row" id="site-nav">
            <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="/agencies/">Agencies</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/meetings/">Meetings</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/agenda/">Agenda</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/documents/">Documents</a>
                </li>
            </ul>
            <form class="form-inline ml-2" role="search" action="/search/" method="post">
                <div class="form-group">
                    <input type="text" name="request" class="form-control" placeholder="Search Documents">
                </div>
                <button type="submit" class="btn search-button">Search</button>
            </form>
        </div>
    </div>
</nav>

https://www.codeply.com/go/ZEyl77GzA8

注意：您使用的是navbar-expand-md，因此导航栏将折叠到 sm 上的切换器中。如果您想在 md 上显示堆叠的菜单/表单，则应将导航栏扩展为 sm。

另见：Bootstrap 4 navbar with 2 rows

Answer 2

将搜索表单的内容放在一个btn-group 中，这样可以将它们放在一起：

        <form class="form-inline mt-3 mb-3" role="search" action="/search/" method="post">
            <div class="btn-group" role="group" aria-label="Basic example">
                <input type="text" name="request" class="form-control" placeholder="Search Documents">
                <button type="submit" class="btn search-button">Search</button>
            </div>
        </form>