使用 Bootstrap 4 的 Css 动画和下拉导航

Question

html代码

<section class="container-fluid">
  <div class="col">
    <div class="row justify-content-md-center">
      <div class="col nav-color card-border">
        <ul class="nav nav-pills">
          <li class="container-custom topBotomBordersIn dropdown">
            <button class="btn-custom-animated dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">nav1dropdown</button>
            <div class="dropdown-menu">
              <button class="btn-custom-animated">dropdown1</button> 
              <button class="btn-custom-animated">dropdown2</button> 
              <button class="btn-custom-animated">dropdown3</button> 
            </div>                
          </li>
          <li class="container-custom topBotomBordersIn">
            <button class="btn-custom-animated">nav2</button> 
            <button class="btn-custom-animated">nav3</button> 
          </li>
        </ul>
      </div>
    </div>
  </div>
</section>

CSS 代码

.center-pills {
  display: flex;
  justify-content: center;
}
.nav-color {
  background-color:deepskyblue;
}
.dropdown-menu {
  background-color: deepskyblue !important;
}
.btn-custom-animated {
  background-color: transparent;
  border: none;
  box-shadow: none;
  outline: none;
}
.btn-custom-animated.active.focus,
.btn-custom-animated.active:focus,
.btn-custom-animated.focus,
.btn-custom-animated.focus:active,
.btn-custom-animated:active:focus,
.btn-custom-animated:focus {
  outline: 0 !important;
  outline-offset: 0 !important;
  background-image: none !important;
  -webkit-box-shadow: none !important;
  box-shadow: none !important;
  background-color: transparent;
  border: none;
  box-shadow: none;
  outline: none;
}
li.container-custom {
  font-family: Raleway;
  margin: 0 auto;
  /*padding: 10em 3em;*/
  text-align: center;
}
li.container-custom button {
  color: #FFF;
  text-decoration: none;
  font: 20px Raleway;
  margin: 0px 10px;
  padding: 10px 10px;
  position: relative;
  z-index: 0;
  cursor: pointer;
}
/* Top and Bottom borders come in */
li.topBotomBordersIn button:before, li.topBotomBordersIn button:after {
  position: absolute;
  left: 0px;
  width: 100%;
  height: 2px;
  background: #FFF;
  content: "";
  opacity: 0;
  transition: all 0.3s;
}
li.topBotomBordersIn button:before {
  top: 0px;
  transform: translateY(-10px);
}
li.topBotomBordersIn button:after {
  bottom: 0px;
  transform: translateY(10px);
}
li.topBotomBordersIn button:hover:before, li.topBotomBordersIn button:hover:after {
  opacity: 1;
  transform: translateY(0px);
}

jsfiddle.net

在这个元素中，我使用的是 Bootstrap 4 和所有 js 插件。

我无法弄清楚第一个按钮(下拉菜单)在动画期间有不同底线的原因。在 jsfiddle 中，下拉菜单中的导航按钮也不起作用，但在元素中它们可以正确设置动画。

Answer 1

问题是按钮有一个类 .dropdown-toggle，它有自己的 css 添加到它的伪元素 .dropdown-toggle:after，只需覆盖它它将正常工作。

.center-pills {
  display: flex;
  justify-content: center;
}
.nav-color {
  background-color:deepskyblue;
}
.dropdown-menu {
  background-color: deepskyblue;
}
.btn-custom-animated {
  background-color: transparent;
  border: none;
  box-shadow: none;
  outline: none;
}
.btn-custom-animated.active.focus,
.btn-custom-animated.active:focus,
.btn-custom-animated.focus,
.btn-custom-animated.focus:active,
.btn-custom-animated:active:focus,
.btn-custom-animated:focus {
  outline: 0 !important;
  outline-offset: 0 !important;
  background-image: none !important;
  -webkit-box-shadow: none !important;
  box-shadow: none !important;
  background-color: transparent;
  border: none;
  box-shadow: none;
  outline: none;
}
li.container-custom {
  font-family: Raleway;
  margin: 0 auto;
  /*padding: 10em 3em;*/
  text-align: center;
}
li.container-custom button {
  color: #FFF;
  text-decoration: none;
  font: 20px Raleway;
  margin: 0px 10px;
  padding: 10px 10px;
  position: relative;
  z-index: 0;
  cursor: pointer;
}
/* Top and Bottom borders come in */
li.topBotomBordersIn button:before, li.topBotomBordersIn button:after {
  position: absolute;
  left: 0px;
  width: 100%;
  height: 2px;
  background: #FFF;
  content: "";
  opacity: 0;
  transition: all 0.3s;
  border: none; /* Added to override css added by class `.dropdown-toggle` */
  margin: 0; /* Added to override css added by class `.dropdown-toggle` */
}
li.topBotomBordersIn button:before {
  top: 0px;
  transform: translateY(-10px);
}
li.topBotomBordersIn button:after {
  bottom: 0px;
  transform: translateY(10px);
}
li.topBotomBordersIn button:hover:before, li.topBotomBordersIn button:hover:after {
  opacity: 1;
  transform: translateY(0px);
}
li.container-custom .dropdown-menu button.btn-custom-animated {
  color: #000;
}

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
<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/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

<section class="container-fluid">
  <div class="col">
    <div class="row justify-content-md-center">
      <div class="col nav-color card-border">
        <ul class="nav nav-pills">
          <li class="container-custom topBotomBordersIn dropdown">
            <button class="btn-custom-animated dropdown-toggle" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">nav1dropdown</button>
            <div class="dropdown-menu">
              <button class="btn-custom-animated">dropdown1</button> 
              <button class="btn-custom-animated">dropdown2</button> 
              <button class="btn-custom-animated">dropdown3</button> 
            </div>                
          </li>
          <li class="container-custom topBotomBordersIn">
            <button class="btn-custom-animated">nav2</button> 
            <button class="btn-custom-animated">nav3</button> 
          </li>
        </ul>
      </div>
    </div>
  </div>
</section>

<script type="text/javascript">
  $('.dropdown-toggle').dropdown();
</script>