折叠弹性列导航时，折叠动画看起来很奇怪

时间：2018-12-09 14:13:22

标签： html css twitter-bootstrap flexbox bootstrap-4

我正在尝试使用引导程序4框架在侧栏中进行导航，这在小型设备的页面顶部显示。

我的方法：

.sidebar {
  background-image: linear-gradient(180deg, rgb(33, 243, 96) 0%, #077710 70%);
}

.sidebar .navbar-brand {
  font-size: 1.1rem;
}

.nav-item {
  font-size: 0.9rem;
  padding-bottom: 0.5rem;
}

.main {
  flex: 1;
}

.main .top-row {
  background-color: #e6e6e6;
  border-bottom: 1px solid #d6d5d5;
}

.nav-item:first-of-type {
  padding-top: 1rem;
}

.nav-item:last-of-type {
  padding-bottom: 1rem;
}

.nav-item a {
  color: #d7d7d7;
  border-radius: 4px;
  height: 3rem;
  display: flex;
  align-items: center;
  line-height: 3rem;
}

.nav-item a.active {
  background-color: rgba(255, 255, 255, 0.25);
  color: white;
}

.nav-item a:hover {
  background-color: rgba(255, 255, 255, 0.1);
  color: white;
}

.content {
  padding-top: 1.1rem;
}

.navbar-toggler {
  background-color: rgba(255, 255, 255, 0.1);
}


/* @media (max-width: 767.98px) { */

.main .top-row {
  display: none;
}


/* Burger-icon animation */

.navbar-toggler {
  position: relative;
}

.navbar-toggler:focus,
.navbar-toggler:active {
  outline: 0;
}

.navbar-toggler span {
  display: block;
  background-color: #444;
  height: 3px;
  width: 25px;
  margin-top: 4px;
  margin-bottom: 4px;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  position: relative;
  left: 0;
  opacity: 1;
}

.navbar-toggler span:nth-child(1),
.navbar-toggler span:nth-child(3) {
  -webkit-transition: transform .35s ease-in-out;
  -moz-transition: transform .35s ease-in-out;
  -o-transition: transform .35s ease-in-out;
  transition: transform .35s ease-in-out;
}

.navbar-toggler:not(.collapsed) span:nth-child(1) {
  position: absolute;
  left: 12px;
  top: 10px;
  -webkit-transform: rotate(135deg);
  -moz-transform: rotate(135deg);
  -o-transform: rotate(135deg);
  transform: rotate(135deg);
  opacity: 0.9;
}

.navbar-toggler:not(.collapsed) span:nth-child(2) {
  height: 12px;
  visibility: hidden;
  background-color: transparent;
}

.navbar-toggler:not(.collapsed) span:nth-child(3) {
  position: absolute;
  left: 12px;
  top: 10px;
  -webkit-transform: rotate(-135deg);
  -moz-transform: rotate(-135deg);
  -o-transform: rotate(-135deg);
  transform: rotate(-135deg);
  opacity: 0.9;
}


/* } */


/* @media (min-width: 768px) {
    contentwrapper {
        flex-direction: row;
    }
    .main{
        position: absolute;
        width: calc(100% - 250px);
        margin-left: 250px;
        float: right;
    }
    .sidebar {
        width: 250px;
        height: 100vh;
        position: fixed;
        top: 0;
        overflow-y: scroll;
    }
    .main .top-row {
        position: sticky;
        top: 0;
    }
    .main > div {
        padding-left: 2rem !important;
        padding-right: 1.5rem !important;
    }
    .navbar-toggler {
        display: none;
    }
    .sidebar .collapse {
        display: block;
    }
} */
<head>
  <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>
</head>

<body>
  <contentwrapper>
    <div class="sidebar">
      <div class="top-row pl-4 navbar navbar-dark">
        <a class="navbar-brand" href="">MyTestPage</a>
        <button class="navbar-toggler navbar-toggler-right collapsed" data-toggle="collapse" data-target="#navbarContent" aria-expanded="false" type="button">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
      </div>
      <ul class="nav flex-column collapse" id="navbarContent">
        <li class="nav-item">
          <a class="nav-link active" href="#">
                        Home
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page1
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page2
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page3
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page4
                    </a>
        </li>
      </ul>
    </div>
    <div class="main">
      <f:render section="Main" />
    </div>
  </contentwrapper>
</body>

注意：我在CSS中评论了媒体查询，以确保它像在移动设备上一样显示

如果现在单击汉堡图标以展开菜单折叠，则可以看到该菜单首先显示为水平放置而不是垂直放置每个菜单点，大约半秒钟后，它便变为原来的样子。

我的错误是什么？如果您知道解决方法，请告诉我。 预先感谢

1 个答案:

答案 0 :(得分：1)

Bootstrap4 具有.nav类，具有以下规则：

.nav {
  display: flex;
  flex-wrap: wrap;
  padding-left: 0;
  margin-bottom: 0;
  list-style: none;
}

所以我们必须使用flex-wrap:nowrap;

覆盖一个规则

我不知道您是否会在网站的另一部分中使用该Bootstrap类，因此也许最好仅在导航时覆盖它：

#navbarContent.nav{
  flex-wrap:nowrap;
}

我还删除了您的@media (max-width: 767.98px) {（^ _ ^;）...因为我认为这没有必要：我认为这是一个移动优先网站。

顺便说一句，这是代码：

<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>
<style>

.sidebar {
  background-image: linear-gradient(180deg, rgb(33, 243, 96) 0%, #077710 70%);
}

.sidebar .navbar-brand {
  font-size: 1.1rem;
}

.nav-item {
  font-size: 0.9rem;
  padding-bottom: 0.5rem;
}

.main {
  flex: 1;
}

.main .top-row {
  background-color: #e6e6e6;
  border-bottom: 1px solid #d6d5d5;
}

.nav-item:first-of-type {
  padding-top: 1rem;
}

.nav-item:last-of-type {
  padding-bottom: 1rem;
}

.nav-item a {
  color: #d7d7d7;
  border-radius: 4px;
  height: 3rem;
  display: flex;
  align-items: center;
  line-height: 3rem;
}

.nav-item a.active {
  background-color: rgba(255, 255, 255, 0.25);
  color: white;
}

.nav-item a:hover {
  background-color: rgba(255, 255, 255, 0.1);
  color: white;
}

.content {
  padding-top: 1.1rem;
}

.navbar-toggler {
  background-color: rgba(255, 255, 255, 0.1);
}



.main .top-row {
  display: none;
}


/* Burger-icon animation */

.navbar-toggler {
  position: relative;
}

.navbar-toggler:focus,
.navbar-toggler:active {
  outline: 0;
}

.navbar-toggler span {
  display: block;
  background-color: #444;
  height: 3px;
  width: 25px;
  margin-top: 4px;
  margin-bottom: 4px;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  position: relative;
  left: 0;
  opacity: 1;
}

.navbar-toggler span:nth-child(1),
.navbar-toggler span:nth-child(3) {
  -webkit-transition: transform .35s ease-in-out;
  -moz-transition: transform .35s ease-in-out;
  -o-transition: transform .35s ease-in-out;
  transition: transform .35s ease-in-out;
}

.navbar-toggler:not(.collapsed) span:nth-child(1) {
  position: absolute;
  left: 12px;
  top: 10px;
  -webkit-transform: rotate(135deg);
  -moz-transform: rotate(135deg);
  -o-transform: rotate(135deg);
  transform: rotate(135deg);
  opacity: 0.9;
}

.navbar-toggler:not(.collapsed) span:nth-child(2) {
  height: 12px;
  visibility: hidden;
  background-color: transparent;
}

.navbar-toggler:not(.collapsed) span:nth-child(3) {
  position: absolute;
  left: 12px;
  top: 10px;
  -webkit-transform: rotate(-135deg);
  -moz-transform: rotate(-135deg);
  -o-transform: rotate(-135deg);
  transform: rotate(-135deg);
  opacity: 0.9;
}

#navbarContent.nav{
  flex-wrap:nowrap;
}




 @media (min-width: 768px) {
    contentwrapper {
        flex-direction: row;
    }
    .main{
        position: absolute;
        width: calc(100% - 250px);
        margin-left: 250px;
        float: right;
    }
    .sidebar {
        width: 250px;
        height: 100vh;
        position: fixed;
        top: 0;
        overflow-y: scroll;
    }
    .main .top-row {
        position: sticky;
        top: 0;
    }
    .main > div {
        padding-left: 2rem !important;
        padding-right: 1.5rem !important;
    }
    .navbar-toggler {
        display: none;
    }
    .sidebar .collapse {
        display: block;
    }
} 

</style>

<contentwrapper>
    <div class="sidebar">
      <div class="top-row pl-4 navbar navbar-dark">
        <a class="navbar-brand" href="">MyTestPage</a>
        <button class="navbar-toggler navbar-toggler-right collapsed" data-toggle="collapse" data-target="#navbarContent" aria-expanded="false" type="button">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
      </div>
      <ul class="nav flex-column collapse" id="navbarContent">
        <li class="nav-item">
          <a class="nav-link active" href="#">
                        Home
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page1
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page2
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page3
                    </a>
        </li>
        <li class="nav-item">
          <a class="nav-link" href="#">
                        Page4
                    </a>
        </li>
      </ul>
    </div>
    <div class="main">
      <f:render section="Main" />
    </div>
  </contentwrapper>

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