Question

我正在使用bootstrap 4导航栏创建菜单。在我的菜单中，有一个下拉菜单。我想自定义下拉菜单的顶部边框，但是问题是顶部边框看起来像image。

我正在尝试添加带有下拉菜单的png图像，以便可以更改顶部边框，但是它看起来不像边框，并且还留有一些空白。

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.4.0/js/tether.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
</head>

<style>
.dropdown {list-style: none; background: green; display: inline-block;}
.dropdown .nav-link {color:#fff; text-decoration: none;}
.dropdown .dropdown-menu a{color: #000; text-decoration: none;}
.dropdown .dropdown-menu{background-image: url("images/arrow.png"); background-repeat: no-repeat;
    background-size: 20px 20px;
	}
.dropdown .btn {background: green; color:#fff;}
.dropdown .btn:hover {background: cyan; color:#000;}
.dropdown .btn:active {background: cyan; color:#000;}
.dropdown .btn:focus {background: cyan; color:#000;}
 .dropdown-item {display: inline-block; width: 100%; padding: 10px 5px;}
.container .dropdown .dropdown-menu a:hover
{
  color: #fff;
  background-color: #b91773;
  border-color: #fff;
}
</style>

<body>

<div class="container">
  <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true"
          aria-expanded="false">
  Dropdown link
</a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
</div>

</body>
</html>

Answer 1

我在背景大小属性中使用了100% 6px。这是所需的输出吗？

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.4.0/js/tether.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
</head>

<style>
.dropdown {list-style: none; background: green; display: inline-block; }
.dropdown .nav-link {color:#fff; text-decoration: none;}
.dropdown .dropdown-menu a{color: #000; text-decoration: none;}
.dropdown .dropdown-menu{
    background-size: 100% 6px;
    background-image: url("https://simimaging.co.uk/wp-content/themes/theme1491_RWD/images/divider.png"); 
    background-repeat: no-repeat;
	}
  .dropdown-menu{
  margin-top:20px;
  border-top:none;}
.dropdown .btn {background: green; color:#fff;}
.dropdown .btn:hover {background: cyan; color:#000;}
.dropdown .btn:active {background: cyan; color:#000;}
.dropdown .btn:focus {background: cyan; color:#000;}
 .dropdown-item {display: inline-block; width: 100%; padding: 10px 5px;}
.container .dropdown .dropdown-menu a:hover
{
  color: #fff;
  background-color: #b91773;
  border-color: #fff;
}

.dropdown-item:nth-of-type(1) {
}
</style>

<body>

<div class="container">
  <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true"
          aria-expanded="false">
  Dropdown link
</a>
        <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
          <a class="dropdown-item" href="#">Action</a>
          <a class="dropdown-item" href="#">Another action</a>
          <a class="dropdown-item" href="#">Something else here</a>
        </div>
      </li>
</div>

</body>
</html>

如何在下拉bootstrap4中放置图像以设置边框

1 个答案: