因此，使用bootstrap 4，我创建了一个导航栏，当屏幕太小时，该导航栏会折叠成一个按钮。当它未折叠时，导航栏将按完美顺序设置。但是，当它折叠在按钮后面时，一个项目(图标图像(居中，而其余项目位于左侧。如何使图标仅在导航栏折叠时向左移动(就像其他项目一样(。
我尝试在图标图像上执行"float-md-left"操作，但是没有进行任何更改。
<!--Navbar-->
<nav class="navbar navbar-expand-lg navbar-dark bg-dark mx-auto">
<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 mx-auto">
<li class="nav-item active">
<a class="nav-link" href="#">The Party<span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Current Stadium</a>
</li>
<a class="navbar-brand mx-auto float-sm-left" href="#"><i class="fas fa-football-ball"></i></a>
<li class="nav-item">
<a class="nav-link" href="#">RSVP</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Stadium History
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">2017 Stadium</a>
<a class="dropdown-item" href="#">2018 Stadium</a>
<a class="dropdown-item" href="#">2019 Stadium</a>
</div>
</li>
</ul>
</div>
</nav>
我明白你的意思了。 由于mx-auto类，这是令人高兴的。
申请mx-auto课程有什么具体原因吗？否则，您可以自行删除。
另外，请删除浮点类。
请查看下面的代码。
<a class="navbar-brand mx-lg-auto" href="#"><i class="fas fa-football-ball"></i></a>
<!-- <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous"> -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.11.2/css/all.css" integrity="sha256-46qynGAkLSFpVbEBog43gvNhfrOj+BmwXdxFgVK/Kvc=" crossorigin="anonymous" />
<nav class="navbar navbar-expand-lg navbar-dark bg-dark mx-auto">
<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 mx-auto">
<li class="nav-item active">
<a class="nav-link" href="#">The Party<span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Current Stadium</a>
</li>
<a class="navbar-brand mx-lg-auto" href="#"><i class="fas fa-football-ball"></i></a>
<li class="nav-item">
<a class="nav-link" href="#">RSVP</a>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Stadium History
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdown">
<a class="dropdown-item" href="#">2017 Stadium</a>
<a class="dropdown-item" href="#">2018 Stadium</a>
<a class="dropdown-item" href="#">2019 Stadium</a>
</div>
</li>
</ul>
</div>
</nav>
<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>