class Custom_Walker_Nav_Menu extends Walker_Nav_Menu {
    // 开始输出每个菜单项
    function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0) {
        // 和默认 Walker 一样处理元素的基础部分
        $classes = empty($item->classes) ? array() : (array) $item->classes;
        $class_names = join(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item));
        $class_names = $class_names ? ' class="' . esc_attr($class_names) . '"' : '';
        $id = apply_filters('nav_menu_item_id', 'menu-item-'. $item->ID, $item);
        $id = $id ? ' id="' . esc_attr($id) . '"' : '';
        $output .= '<li' . $id . $class_names .'>';
        $atts = array();
        $atts['title']  = ! empty( $item->attr_title ) ? $item->attr_title : '';
        $atts['target'] = ! empty( $item->target )     ? $item->target     : '';
        $atts['rel']    = ! empty( $item->xfn )        ? $item->xfn        : '';
        $atts['href']   = ! empty( $item->url )        ? $item->url        : '';
        $atts = apply_filters('nav_menu_link_attributes', $atts, $item, $args);
        $attributes = '';
        foreach ( $atts as $attr => $value ) {
            if ( ! empty( $value ) ) {
                $value = ( 'href' === $attr ) ? esc_url( $value ) : esc_attr( $value );
                $attributes .= ' ' . $attr . '="' . $value . '"';
            }
        }
        $item_output = $args->before;
        $item_output .= '<a'. $attributes .'>';
        $item_output .= $args->link_before . apply_filters('the_title', $item->title, $item->ID) . $args->link_after;
        // 添加分类项的文章数量
        if ($item->object == 'category') {
            $category_id = $item->object_id;
            $category = get_category($category_id);
            if ($category) {
                $count = $category->count;
                $item_output .= ' (' . $count . ')';
            }
        }
        $item_output .= '</a>';
        $item_output .= $args->after;
        $output .= apply_filters('walker_nav_menu_start_el', $item_output, $item, $depth, $args);
    }
}

function zib_menu_items($location = 'topmenu', $echo = true)
{
    $args = array(
        'container'       => false,
        'container_class' => 'nav navbar-nav',
        'echo'            => false,
        'fallback_cb'     => false,
        'items_wrap'      => '<ul class="nav navbar-nav">%3$s</ul>',
        'theme_location'  => $location,
        'walker'          => new Custom_Walker_Nav_Menu(), // 使用自定义 Walker 类
    );
    if (!wp_is_mobile()) {
        $args['depth'] = 0;
    }
    $menu = wp_nav_menu($args);
    if (!$menu && is_super_admin()) {
        $menu = '<ul class="nav navbar-nav"><li><a href="' . admin_url('nav-menus.php') . '" class="loaderbt">添加导航菜单</a></li></ul>';
    }
    if ($echo) {
        echo $menu;
    } else {
        return $menu;
    }
}