如何将下拉列表添加到浮动按钮

Question

我的 html 页面中有一个浮动按钮

.float{
  position:fixed;
  width:60px;
  height:60px;
  bottom:40px;
  right:40px;
  background-color:#0C9;
  color:#FFF;
  border-radius:50px;
  text-align:center;
  box-shadow: 2px 2px 3px #999;
}

.my-float{
  margin-top:22px;
}


.label-container{
  position:fixed;
  bottom:48px;
  right:105px;
  display:table;
  visibility: hidden;
}

.label-text{
  color:#FFF;
  background:rgba(51,51,51,0.5);
  display:table-cell;
  vertical-align:middle;
  padding:10px;
  border-radius:3px;
}

.label-arrow{
  display:table-cell;
  vertical-align:middle;
  color:#333;
  opacity:0.5;
}

.my-float{
  font-size:24px;
  margin-top:18px;
}

a.float + div.label-container {
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.5s ease;
}

a.float:hover + div.label-container{
  visibility: visible;
  opacity: 1;
}

a.float:hover .user-req-list {
  visibility: collapse;
}


.float{
  position:fixed;
  width:60px;
  height:60px;
  bottom:40px;
  right:40px;
  background-color:#0C9;
  color:#FFF;
  border-radius:50px;
  text-align:center;
  box-shadow: 2px 2px 3px #999;
}

.my-float{
  margin-top:22px;
}


.label-container{
  position:fixed;
  bottom:48px;
  right:105px;
  display:table;
  visibility: hidden;
}

.label-text{
  color:#FFF;
  background:rgba(51,51,51,0.5);
  display:table-cell;
  vertical-align:middle;
  padding:10px;
  border-radius:3px;
}

.label-arrow{
  display:table-cell;
  vertical-align:middle;
  color:#333;
  opacity:0.5;
}

.my-float{
  font-size:24px;
  margin-top:18px;
}

a.float + div.label-container {
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.5s ease;
}

a.float:hover + div.label-container{
  visibility: visible;
  opacity: 1;
}

a.float:hover .user-req-list {
  visibility: collapse;
}

<body>
  <a class="float">
    <i class="fa fa-plus my-float"></i>
  </a>
  <div class="label-container">
    <div class="label-text">User Join Requests</div>
    <i class="fa fa-play label-arrow"></i>
  </div>
</body>

我想向此按钮添加一个下拉列表，这样当我在其上 press/hover 时，该列表将出现并且用户将能够与其进行交互。我试图从 bootstrap 添加一个下拉列表，就像我在 here 中看到的那样，但是列表没有显示，你可以在这里看到

.float{
  position:fixed;
  width:60px;
  height:60px;
  bottom:40px;
  right:40px;
  background-color:#0C9;
  color:#FFF;
  border-radius:50px;
  text-align:center;
  box-shadow: 2px 2px 3px #999;
}

.my-float{
  margin-top:22px;
}


.label-container{
  position:fixed;
  bottom:48px;
  right:105px;
  display:table;
  visibility: hidden;
}

.label-text{
  color:#FFF;
  background:rgba(51,51,51,0.5);
  display:table-cell;
  vertical-align:middle;
  padding:10px;
  border-radius:3px;
}

.label-arrow{
  display:table-cell;
  vertical-align:middle;
  color:#333;
  opacity:0.5;
}

.my-float{
  font-size:24px;
  margin-top:18px;
}

a.float + div.label-container {
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.5s ease;
}

a.float:hover + div.label-container{
  visibility: visible;
  opacity: 1;
}

a.float:hover .user-req-list {
  visibility: collapse;
}

.user-req-list {
  visibility: hidden;
}

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<div class="dropdown">
    <a class="float dropdown-toggle"  role="button" id="dropdownMenuLink" data-toggle="dropdown"
       aria-haspopup="true" aria-expanded="false">
      <i class="fa fa-plus my-float"></i>
    </a>
    <div class="label-container">
      <div class="label-text">User Join Requests</div>
      <i class="fa fa-play label-arrow"></i>
    </div>
    <div class="dropdown-menu" aria-labelledby="dropdownMenuLink">
      <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>
  </div>

如您所见，它不起作用，当我将鼠标悬停在按钮上时，列表没有显示。有什么办法可以做我想做的事吗？另请注意，我的项目在 angular 6 中，因此任何 javascript 大部分都不在画面中。

Answer 1

实际上，您的代码可以正常工作。您只是没有为下拉菜单添加 JS 要求。 See documentation.

Dropdowns are built on a third party library, Popper.js, which provides dynamic positioning and viewport detection. Be sure to include popper.min.js before Bootstrap’s JavaScript or use bootstrap.bundle.min.js / bootstrap.bundle.js which contains Popper.js. Popper.js isn’t used to position dropdowns in navbars though as dynamic positioning isn’t required.

但是请注意，将鼠标悬停在按钮上将无法访问下拉菜单。根据documentation, this is an intentional design decision.

.float{
  position:fixed;
  width:60px;
  height:60px;
  bottom:40px;
  right:40px;
  background-color:#0C9;
  color:#FFF;
  border-radius:50px;
  text-align:center;
  box-shadow: 2px 2px 3px #999;
}

.my-float{
  margin-top:22px;
}


.label-container{
  position:fixed;
  bottom:48px;
  right:105px;
  display:table;
  visibility: hidden;
}

.label-text{
  color:#FFF;
  background:rgba(51,51,51,0.5);
  display:table-cell;
  vertical-align:middle;
  padding:10px;
  border-radius:3px;
}

.label-arrow{
  display:table-cell;
  vertical-align:middle;
  color:#333;
  opacity:0.5;
}

.my-float{
  font-size:24px;
  margin-top:18px;
}

a.float + div.label-container {
  visibility: hidden;
  opacity: 0;
  transition: visibility 0s, opacity 0.5s ease;
}

a.float:hover + div.label-container{
  visibility: visible;
  opacity: 1;
}

a.float:hover .user-req-list {
  visibility: collapse;
}

.user-req-list {
  visibility: hidden;
}

<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/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">


<div class="dropdown">
  <a class="float dropdown-toggle"  role="button" id="dropdownMenuButton" data-toggle="dropdown"
     aria-haspopup="true" aria-expanded="false">
    <i class="fa fa-plus my-float"></i>
  </a>
  <div class="label-container">
    <div class="label-text">User Join Requests</div>
    <i class="fa fa-play label-arrow"></i>
  </div>
  <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
    <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>
</div>

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