Boostrap 4折叠侧栏必须点击两次

Question

我正试图创建一个可折叠的左侧菜单，基于那个漂亮的例子。Codeply的例子

下面是减少的代码。

<div class="row" id="body-row">
    <!-- Sidebar -->
    <div id="sidebar-container" class="sidebar-expanded d-none d-md-block">
        <ul class="list-group">        <!-- Menu with submenu -->
            <a href="#submenu1" data-toggle="collapse" aria-expanded="false" class="bg-dark list-group-item list-group-item-action flex-column align-items-start">
                <div class="d-flex w-100 justify-content-start align-items-center">
                    <span class="menu-collapsed">Dashboard</span>
                    <span class="submenu-icon ml-auto"></span>
                </div>
            </a>
            <!-- Submenu content -->
            <div id='submenu1' class="collapse sidebar-submenu">
                <a href="#" class="list-group-item list-group-item-action bg-dark text-white">
                    <span class="menu-collapsed">Chahgag</span>
                </a>
                <a href="#" class="list-group-item list-group-item-action bg-dark text-white">
                    <span class="menu-collapsed">Reports</span>
                </a>
                <a href="#" class="list-group-item list-group-item-action bg-dark text-white">
                    <span class="menu-collapsed">Tables</span>
                </a>
            </div>
            <a href="#submenu2" data-toggle="collapse" aria-expanded="false" class="bg-dark list-group-item list-group-item-action flex-column align-items-start">
                <div class="d-flex w-100 justify-content-start align-items-center">
                    <span class="menu-collapsed">Profile</span>
                    <span class="submenu-icon ml-auto"></span>
                </div>
            </a>
            <!-- Submenu content -->
            <div id='submenu2' class="sidebar-submenu">
                <a href="#" class="list-group-item list-group-item-action bg-dark text-white">
                    <span class="menu-collapsed">Settings</span>
                </a>
                <a href="#" class="list-group-item list-group-item-action bg-dark text-white">
                    <span class="menu-collapsed">Password</span>
                </a>
            </div>
        </ul><!-- List Group END-->
    </div><!-- sidebar-container END -->
    <!-- MAIN -->
    <div class="col p-4">
        Content
    </div><!-- Main Col END -->
</div><!-- body-row END -->

CSS

/* Closed submenu icon */
#sidebar-container .list-group .list-group-item[aria-expanded="false"] .submenu-icon::after {
  content: " \f0d7";
  font-family: FontAwesome;
  display: inline;
  text-align: right;
  padding-left: 10px;
}
/* Opened submenu icon */
#sidebar-container .list-group .list-group-item[aria-expanded="true"] .submenu-icon::after {
  content: " \f0da";
  font-family: FontAwesome;
  display: inline;
  text-align: right;
  padding-left: 10px;
}

与这个例子相反，我想在页面加载时打开菜单，问题是如果我把侧边栏菜单中的 "折叠 "去掉（在submenu2上完成），子菜单就会打开，但用户必须点击两次才能折叠。

问题是，如果我把sidebar-menu中的 "collapse "去掉（在submenu2中就有），子菜单是打开了，但用户必须点击两次才能折叠。

下面是一个 减少的Codeply 显示问题。

Answer 1

在子菜单上添加 "show "类而不是删除 "collapse "类就可以了。