我已经安装了：popper.js，bootstrap和jquery。 我的角度 json 文件是：
"styles": [
"src/styles.css",
"../node_modules/bootstrap/dist/css/bootstrap.min.css"
],
"scripts": [
"../node_modules/jquery/dist/jquery.min.js",
"../node_modules/popper.js/dist/umd/popper.min.js",
"../node_modules/bootstrap/dist/js/bootstrap.min.js"
]
在我导入的styles.css文件中：@import '~bootstrap/dist/css/bootstrap.min.css';.
即使我做了这些事情，导航栏中的下拉菜单也不起作用：我的 html 代码是：
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</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>
<form class="form-inline my-2 my-lg-0">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button>
</form>
</div>
</nav>
我从以下位置获得代码：https://getbootstrap.com/docs/4.0/components/navbar/
提前谢谢你！
我认为您正在设置访问样式和脚本的路径。
节点模块位于主项目文件夹中;因此只跳过一个文件夹，您跳过/跳转两个文件夹(../)
"styles": [
"src/styles.css",
"./node_modules/bootstrap/dist/css/bootstrap.min.css"
],
"scripts": [
"./node_modules/jquery/dist/jquery.min.js",
"./node_modules/popper.js/dist/umd/popper.min.js",
"./node_modules/bootstrap/dist/js/bootstrap.min.js"
]