bootstrap-4 - Bootstrap 4导航栏切换器未显示

Question

这是我第一次尝试使用Bootstrap 4 beta。我现在有一个在BS3中建立并运行的慈善团体网站。我正在使用固定的顶部导航栏和自定义CSS。当站点较小而不是全屏显示时，切换图标不会显示。你能帮助我吗？我希望它像导航链接一样为白色，并且悬停将链接更改为已读。
这是头部链接

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">    
<!-- Custom styles for this template -->
<link href="css/custombs4.css" rel="stylesheet"> `

js代码链接在页面底部

<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/1.11.0/umd/popper.min.js" integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
 <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js" integrity="sha384-h0AbiXch4ZDo7tp9hKZ4TsHbi047NrKGLO3SEJAg45jXxnGIfYzk4Si90RDIqNm1" crossorigin="anonymous"></script>

这是我的代码。

/* Navbar */

.navbar-custom {
    background-color: #3193de;
}


/* change the brand and text color */

.navbar-custom .navbar-brand,
.navbar-custom .navbar-text {
    text-decoration: none; color: #fff;
}


/* change the link color */

.navbar-custom .navbar-nav .nav-link {
   text-decoration: none; color: #fff;
}


/* change the color of active or hovered links */

.navbar-custom .nav-item.active .nav-link,
.navbar-custom  {
  text-decoration: none;  color: #fff;
}

.nav-item .nav-link:hover {
    text-decoration: none; color: #ff0000;
}

/* for dropdown only - change the color of dropdown */

.navbar-custom .dropdown-menu {
    background-color: #3193de;
}

.navbar-custom .dropdown-item {
    text-decoration: none; color: #fff;
}

.navbar-custom .dropdown-item:hover,
.navbar-custom .dropdown-item:focus {
    text-decoration: none; color: #ff0000;
    background-color:#3193de;
}
.navbar-header .navbar-toggler {
  border: 0;
}
.navbar-toggler-icon {
  color: #fff;
}
.navbar-toggler-icon:hover {
  background: #ff0000;
}

<nav class="navbar navbar-custom navbar-expand-md">
      
<a class="navbar-brand" href="#">AHEPA 215</a>


<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbar-custom" aria-controls="navbar-custom" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>
      
     
<div class="collapse navbar-collapse" id="navbarCollapse">
        
<ul class="navbar-nav mx-auto">
          
<li class="nav-item">
            
<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" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">About</a>
                
<div class="dropdown-menu dropdown-menu-right">
                    
<a class="dropdown-item" href="#">AHEPA</a>
                    
<a class="dropdown-item" href="#">Chapter 215 Brothers</a>
                    
</li>          
<li class="nav-item">
            
<a class="nav-link" href="scholarship.html">Scholarships</a>
          
</li>
   
<li class="nav-item">
            
<a class="nav-link" href="photos.html">Photos</a>
          
</li>
 
<li class="nav-item">
            
<a class="nav-link" href="join.html">Join</a>
          
</li>
 
<li class="nav-item">
            
<a class="nav-link" href="calendar.html">Calendar</a>
          
</li>
 
<li class="nav-item">
            
<a class="nav-link" href="contact.html">Contact</a>
          
</li>
      
</ul>

<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="https://www.facebook.com/portsmouth.ahepa" target="_blank"><i class="fa fa-facebook"></i></a>
</li> 
<li class="nav-item">
<a class="nav-link" href="mailto:ahepa215@gmail.com"><i class="fa fa-envelope"></i></a>
</li> 
</ul>       
</div>
    
</nav>

该页面位于此处 http://ahepa215.org/navbar-top-fixed.html

Answer 1

@mlegg，由于id属性的值与data-toggler上的button属性的值不同，因此切换器图标未切换。下面的代码显示了它应该是什么。

<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>


<div class="collapse navbar-collapse" id="navbarCollapse">

至于切换图标的样式，您可以使用以下代码:

.navbar-toggler-icon {
        background-image: url("data:image/svg+xml;charset=utf8,%3Csvg viewBox='0 0 32 32' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath stroke='rgba(255,255,255, 1)' stroke-width='2' stroke-linecap='round' stroke-miterlimit='10' d='M4 8h24M4 16h24M4 24h24'/%3E%3C/svg%3E");
}

要全面了解此处发生的情况，请在 stack overflow question中 checkout @ZimSystem的答案。最终，您必须在 background-image的URL中设置stroke属性的值，如下所示:

stroke='rgba(255,255,255, 1)'

checkout 此 codeply project