命令col-xs-whatever不起作用，并在移动视图或小屏幕上创建断行。
注意：我还测试了类.col-作为Bootstrap 4在文档中指定但它仍然不起作用。
它没有正确调整大小并堆积，这是相关代码：
.navbar{
background-image: cornflowerblue;
}
#mainNav{
border: 5px solid black;
margin: 3%;
background-color: white;
}
body{
background-color: grey;
}
#navContent{
background-color: white;
margin: 3%;
}
#final{
border: 5px solid black;
margin: 3%;
background-color: white;
}
#searchFormContent{
margin: auto;
width: 80%;
}
#navToggler{
float: right;
}
.navbar-toggler{
float:right;
}<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></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>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<body>
<div class="container-fluid">
<section class="row" id="mainNav">
<div class="col-12">
<nav class="navbar sticky-top navbar-expand-md">
<div class="col-xs-1 col-md-2">
<a class="navbar-brand" href="#">Brand</a>
</div>
<div class="col-xs-10 col-md-7">
<form class="form-inline" id="searchForm" role="search">
<div class="input-group" id="searchFormContent">
<input class="form-control" type="text" placeholder="Busqueda">
<div class="input-group-btn">
<button class="btn btn-secondary" type="button"><i class="fa fa-search"></i></button>
</div>
</div>
</form>
<span id="destiny1"></span>
</div>
<div class="col-xs-1 col-md-3">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navToggler" aria-controls="navToggler" aria-expanded="false" aria-label="Toggle navigation">
<i class="fa fa-bars"></i>
</button>
<div class="collapse navbar-collapse" id="navToggler">
<ul class="navbar-nav">
<li class="nav-item"><a class="nav-link" href="#">Option 1</a></li>
<li class="nav-item"><a class="nav-link" href="#">Option 2</a></li>
</ul>
</div>
<span id="destiny2"></span>
</div>
</nav>
</div>
</section>
</div>
</body>
答案 0 :(得分：4)
我不知道这是否是你想要的结果，因为你没有指明。
我已将col-xs-whatever更改为col-whatever，之后您将row上的边距和边框应用于#mainNav，这就是为什么所有列都无法放入内部的原因。
因此，我将row移到了包装导航栏中，并从row
#mainNav
以下是更改的代码：
.navbar{
background-image: cornflowerblue;
}
#mainNav{
border: 5px solid black;
margin: 3%;
background-color: white;
}
body{
background-color: grey;
}
#navContent{
background-color: white;
margin: 3%;
}
#final{
border: 5px solid black;
margin: 3%;
background-color: white;
}
#searchFormContent{
margin: auto;
width: 80%;
}
#navToggler{
float: right;
}
.navbar-toggler{
float:right;
}<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></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>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">
<div class="container-fluid">
<section id="mainNav">
<nav class="navbar sticky-top navbar-expand-md row">
<div class="col-2 col-md-2">
<a class="navbar-brand" href="#">Brand</a>
</div>
<div class="col-8 col-md-7">
<form class="form-inline" id="searchForm" role="search">
<div class="input-group" id="searchFormContent">
<input class="form-control" type="text" placeholder="Busqueda">
<div class="input-group-btn">
<button class="btn btn-secondary" type="button"><i class="fa fa-search"></i></button>
</div>
</div>
</form>
<span id="destiny1"></span>
</div>
<div class="col-2 col-md-3">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navToggler" aria-controls="navToggler" aria-expanded="false" aria-label="Toggle navigation">
<i class="fa fa-bars"></i>
</button>
<div class="collapse navbar-collapse" id="navToggler">
<ul class="navbar-nav">
<li class="nav-item"><a class="nav-link" href="#">Option 1</a></li>
<li class="nav-item"><a class="nav-link" href="#">Option 2</a></li>
</ul>
</div>
<span id="destiny2"></span>
</div>
</nav>
</section>
</div>
答案 1 :(得分：0)