如何向Wordpress主题添加子菜单（下拉）功能？

Question

我正在开发自定义Wordpress主题，这是我的代码：

header.php：

          <div class="mobile-menu">
                <div class="mobile-menu-wrapper">
                    <div class="va-parent">
                        <div class="va-child">
                            <?php
                            $mobile_menu = array(
                                'theme_location'  => 'primary',
                                'container' => ""
                            );
                            wp_nav_menu( $mobile_menu );
                            ?>
                        </div>
                    </div>
                </div>
            </div>
            <!-- Navigation -->
            <nav class="navbar navbar-inverse navbar-fixed-top" role="navigation">
                <div class="container">
                    <!-- Brand and toggle get grouped for better mobile display -->
                    <div class="navbar-header">
                        <button type="button" class="mobile-menu-button">
                            <span class="sr-only">Toggle navigation</span>
                            <span class="icon-bar"></span>
                            <span class="icon-bar"></span>
                            <span class="icon-bar"></span>
                        </button>
                    </div>
                    <!-- Collect the nav links, forms, and other content for toggling -->
                    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
                        <?php
                        $main_menu = array(
                            'theme_location'  => 'main',
                            'menu_class'      => 'nav navbar-nav',
                            'menu_id'         => 'menu',
                            'echo'            => true,
                            'fallback_cb'     => 'wp_page_menu',
                            'items_wrap'      => '<ul id="wrap" class="nav navbar-nav">%3$s</ul>',
                            'depth'           => 0,
                        );
                        wp_nav_menu( $main_menu );
                        ?>
                    </div>
                    <!-- /.navbar-collapse -->
                </div>

functions.php

register_nav_menus( array(
        'main' => esc_html__( 'Main', '_s' ),
    ) );

如何向其中添加下拉子菜单功能？我应该注册另一个菜单吗？引导程序是否引起问题？

谢谢。

Answer 1

将'depth' => 0提高到'depth' => 1参数$main_menu创建中的值。