导航栏下拉菜单未扩展答案

【问题标题】：Navbar Dropdown not expanding导航栏下拉菜单未扩展
【发布时间】：2020-10-03 01:10:49
【问题描述】：

我正在尝试将带有下拉菜单的导航栏集成到我的 Angular 应用程序中。为了确保一切正常，我完全复制了官方Bootstrap 页面上的说明。

由于某种原因，菜单不会展开：（单击似乎会重新加载页面）

我不知道去哪里看：-/

<!-- statisches menu anzeigen -->
<div class="row">
  <div class="col-md-9">

    <nav *ngIf="currentUser" class="navbar navbar-expand navbar-dark bg-primary">
      <a class="navbar-brand" routerLink="/home">S.GG-Community</a>

      <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
      </button>

      <div class="collapse navbar-collapse" id="navbarSupportedContent">
        <ul class="navbar-nav mr-auto">
          <li class="nav-item active">
            <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">Link</a>
          </li>
          <li class="nav-item dropdown">
            <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
              Dropdown
            </a>
            <div class="dropdown-menu" aria-labelledby="navbarDropdown">
              <a class="dropdown-item" href="#">Action</a>
              <a class="dropdown-item" href="#">Another action</a>
              <div class="dropdown-divider"></div>
              <a class="dropdown-item" href="#">Something else here</a>
            </div>
          </li>
          <li class="nav-item">
            <a class="nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Disabled</a>
          </li>
        </ul>
      </div>

    </nav>

  </div>
</div>

<!-- main app container: maximaler platz nutzen aus index.html -->
<div class="container-fluid">
  <div class="row">
    <div class="col-md-9">
      <router-outlet></router-outlet>
    </div>
  </div>
</div>

【问题讨论】：

标签： angular twitter-bootstrap bootstrap-4 navbar

【解决方案1】：

这似乎是一个问题，因为您没有正确使用 Angular Ng 模块。可能使用 [routerLink]="#" 而不是 href="#" 可以解决此问题。

为什么不考虑使用 Angular 材质库？ https://material.angular.io/components/menu/overview

它在不断发展的应用中运行良好且更易于实施。

【讨论】：

【解决方案2】：

您还必须在 html 页面的 </body> 结束标记之前添加 bootstrap JS CDN 链接，以使下拉菜单可用。

<!doctype html>
<html lang="en">

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

  <!-- Bootstrap CSS -->
  <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

  <title>Hello, world!</title>
</head>

<body>



  <!-- Your Navbar Contenr --> 
  <h1>Hello, world!</h1>





  <!-- These three script tags are required in order to make the navbar dropdown workable and many other functionality -->

  <!-- jQuery first, then Popper.js, then Bootstrap JS -->
  <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/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
  <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
</body>

</html>

【讨论】：