在 Bootstrap 4 中折叠时如何用图标替换导航栏品牌？

Question

这里是 boostrap 的新手。那么，当导航栏在 Bootstrap 4 中进入折叠模式时，如何将导航栏品牌替换为图标（例如来自 Fontawesome 的图标）或自定义图像徽标？

我的代码如下：

<nav class="navbar navbar-expand-lg navbar-dark bg-dark fixed-top">
<!-- <div class="container">  --><!-- you can turn this container off/on-->
        <a href="#" class="navbar-brand">Anime Battlegrounds</a>
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>

    <div class="collapse navbar-collapse" id="navbarNavAltMarkup">
    <!-- collapse class will hide everything in the navbar once we hit mobile display -->
        <div class="navbar-nav">
            <a class="nav-item nav-link active" href="#">Popular</a>
            <a class="nav-item nav-link active" href="#">Anime List</a>
            <a class="nav-item nav-link active" href="#">Schedule</a>
        </div>

        <div class="navbar-nav ml-auto">
            <a class="nav-item nav-link active" href="#">Sign Up</a>
            <a class="nav-item nav-link active" href="#">Login</a>
        </div>

        <form class="form-inline my-2 my-lg-0">
            <input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
            <button class="btn btn-outline-primary my-2 my-sm-0 btn1" type="submit">Search</button>
        </form>
    </div>
<!-- </div> -->

Answer 1

使用与导航栏断点对应的 Bootstrap 4显示工具。

演示：https : //www.codeply.com/go/9KbjsZ6pGP

<a href="#" class="navbar-brand">
   <span class="d-lg-inline-block d-none">Anime Battlegrounds</span>
   <i class="fa fa-star d-inline-block d-lg-none"></i>
</a>

d-lg-inline-block d-none表示在 lg 及以上显示，在 lgd-none下方隐藏 ( )
d-inline-block d-lg-none表示在 lg 及上方隐藏，在 lgd-inline-block下方显示 ( )