如何在引导4中为响应切换菜单设置自定义断点

Question

如何设置自定义断点在引导4响应切换菜单时，我将设置示例1200断点比我的切换菜单显示时，我的屏幕尺寸小于1200宽度。当我输入任何大小的屏幕设置切换菜单时，我想要断点。任何朋友都有例子请给我。

注意:请附加引导程序4js，而不是try.

​

header .navbar {
      background-color: #000;
    }
    header .navbar-light .navbar-brand {
      color: #fff;
    }
    header .navbar-light .navbar-nav .nav-link {
      color: #fff;
    }
    header .navbar-light .navbar-toggler {
      background-color: #fff;
    }

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
<header>
      <nav class="navbar navbar-expand-lg navbar-light">
        <a class="navbar-brand" href="#">Navbar</a>
        <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 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="#">About Us</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="#">Our Services</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="#">Contact</a>
            </li>
          </ul>
          <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 my-2 my-sm-0" type="submit">Search</button>
          </form>
        </div>
      </nav>
    </header>

​

Answer 1

如果您想要有一个断点，您应该使用@media查询，用于exmaple：

@media screen and (max-width: 1200px) {
    header .navbar {
      background-color: #000;
    }
    header .navbar-light .navbar-brand {
      color: #fff;
    }
    header .navbar-light .navbar-nav .nav-link {
      color: #fff;
    }
    header .navbar-light .navbar-toggler {
      background-color: #fff;
    }
}

只有当屏幕小于或等于1200 to时，才会切换，

或

如果您想更具体地了解断点：

   @media screen and (min-width: 768px) and (max-width: 1200px) {
//this will only toggle if your screen is between 1200px and 767px
    }

Answer 2

我希望这是你问题的答案。不需要自定义主资产，只需使用外部内容(可折叠导航条)进行引导。

JSfiddle：https://jsfiddle.net/fzb07qsd/

HTML：

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>

<div class="pos-f-t">
  <nav class="navbar navbar-dark bg-dark">
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarToggleExternalContent" aria-controls="navbarToggleExternalContent" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
        
  </nav>
     <div class="collapse" id="navbarToggleExternalContent">
    <div class="bg-dark p-4">
      <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="#">About Us</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="#">Our Services</a>
            </li>
            <li class="nav-item">
              <a class="nav-link" href="#">Contact</a>
            </li>
          </ul>
                     <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 my-2 my-sm-0" type="submit">Search</button>
          </form>
    </div>
  </div>
</div>