如何在Bootstrap 4.1中的悬停上创建下拉子菜单？

时间：2018-07-19 04:31:12

标签： html css hover bootstrap-4

我正在一个网站上，想要在Bootstrap 4.1上的悬停中创建一个下拉子菜单

我用来在悬停时创建下拉菜单的HTML代码是：

<div class="navbar-collapse text-center" id="navbarResponsive">
  <ul class="navbar-nav ml-auto">

    <li class="nav-item dropdown">
      <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
      main menu
    </a>
      <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
        <a class="dropdown-item" href="#">A</a>
        <a class="dropdown-item" href="#">B</a>
        <a class="dropdown-item" href="#">C</a>
        <a class="dropdown-item" href="#">D</a>
      </div>
    </li>

    <button type="submit" onclick="location.href='/M';" class="btn btn-default">R</button>

  </ul>
</div>



问题陈述：

我想知道我应该在上面的代码中进行哪些更改，以使D悬停在D上；显示了下拉菜单项E，F，G，H 。

5 个答案:

答案 0 :(得分：11)

此 codepen 链接提供了您的答案：link

基本上创建一个这样的结构

<li>
    <a href="#" class="dropdown-toggle" data-toggle="dropdown">D <b class="caret"></b></a>
    <ul class="dropdown-menu multi-level">
        <li><a href="#">E</a></li>
        <li><a href="#">F</a></li>
        <li><a href="#">G</a></li>
        <li class="divider"></li>
        <li class="dropdown-submenu">
            <a href="#" class="dropdown-toggle" data-toggle="dropdown">H</a>
            <ul class="dropdown-menu">
                <li><a href="#">I</a></li>
                <li><a href="#">J</a></li>
                <li><a href="#">K</a></li>
            </ul>
        </li>
    </ul>
</li>

我已在此答案上方的代码笔和结帐链接中为您编写了完整代码。

答案 1 :(得分：7)

这可能会帮助您..... 

.dropdown:hover>.dropdown-menu {
  display: block;
}
.dropdown-item:hover>.dropdown-menu {
  display: block;
}
ul li{
list-style-type:none;
display: inline;
}

.navbar-nav .nav-link{display:inline-block;}
   
.ml-auto {display:inline-block!important;}

.dropdown>.dropdown-toggle:active {
  pointer-events: none;
}
<!doctype html>
<html lang="en">

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css" integrity="sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B" crossorigin="anonymous">

  <title>Dropdown submenu on hover</title>
</head>

<body>

  <div class="navbar-collapse text-center" id="navbarResponsive">
    <ul class="navbar-nav ml-auto">
 <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          Main menu
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">A</a>
          <a class="dropdown-item" href="#">B</a>
          <a class="dropdown-item" href="#">C</a>
          <a class="dropdown-item nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          D
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">E</a>
          <a class="dropdown-item" href="#">F</a>
          <a class="dropdown-item" href="#">G</a>
          <a class="dropdown-item" href="#">H</a>
        </div>
        </div>
      </li>
    </ul>
  </div>

  <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/js/bootstrap.min.js" integrity="sha384-o+RDsa0aLu++PJvFqy8fFScvbHFLtbvScb8AjopnFD+iEQ7wo/CG0xlczd+2O/em" crossorigin="anonymous"></script>
</body>

</html>

答案 2 :(得分：4)

您只需要在CSS下方添加即可。

.dropdown:hover>.dropdown-menu {
  display: block;
}

.dropdown>.dropdown-toggle:active {
  pointer-events: none;
}
<!doctype html>
<html lang="en">

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/css/bootstrap.min.css" integrity="sha384-Smlep5jCw/wG7hdkwQ/Z5nLIefveQRIY9nfy6xoR1uRYBtpZgI6339F5dgvm/e9B" crossorigin="anonymous">

  <title>Dropdown submenu on hover</title>
</head>

<body>

  <div class="navbar-collapse text-center" id="navbarResponsive">
    <ul class="navbar-nav ml-auto">
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
          main menu
        </a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">A</a>
          <a class="dropdown-item" href="#">B</a>
          <a class="dropdown-item" href="#">C</a>
          <a class="dropdown-item" href="#">D</a>
        </div>
      </li>
      <button type="submit" onclick="location.href='/M';" class="btn btn-default">R</button>
    </ul>
  </div>

  <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.2/js/bootstrap.min.js" integrity="sha384-o+RDsa0aLu++PJvFqy8fFScvbHFLtbvScb8AjopnFD+iEQ7wo/CG0xlczd+2O/em" crossorigin="anonymous"></script>
</body>

</html>

答案 3 :(得分：1)

  1. 首先，创建一个新的CSS文件，并根据需要命名。在我的情况下，该文件称为“ my_own.css”。

  2. 在链接到Bootstrap之后将其链接到您的页面。因此，到目前为止，我们有如下内容：

    <link rel="stylesheet" type="text/css" href="bootstrap.css">
<link rel="stylesheet" type="text/css" href="my_own.css">
  3. 只需将以下位添加到您的自定义css文件中，并尽量不要更改原始的引导文件，因为一旦进行引导更新，它将再次被替换。

li.dropdown:hover > .dropdown-menu {
    display: block;
}

答案 4 :(得分：0)

我建议在媒体查询中使用：hover样式。 因为在手机上它必须是可点击的。 这是例子

/* ============ desktop view ============ */
@media all and (min-width: 992px) {
    .navbar .nav-item .dropdown-menu{ display: none; }
    .navbar .nav-item:hover .nav-link{ color: #fff;  }
    .navbar .nav-item:hover .dropdown-menu{ display: block; }
    .navbar .nav-item .dropdown-menu{ margin-top:0; }
}   
/* ============ desktop view .end// ============ */

您还可以添加淡入淡出的动画，这是代码：https://bootstrap-menu.com/detail-animation.html

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