我试图在函数中使用以下代码。php以显示带有类别的菜单（实际上是自定义分类法）。我只是想让它在当前页面上显示活动状态。我做错了什么？

我还看到$category = get_category($mycatid); 行不填充$category 变量

<?php
class walker_archives extends Walker_Nav_Menu
{
    public function start_el( &$output, $item, $depth, $args )
    {
        $attributes  = \'\';

        ! empty ( $item->attr_title )
            and $item->attr_title !== $item->title
            and $attributes .= \' title="\' . esc_attr( $item->attr_title ) .\'"\';

        ! empty ( $item->url )
            and $attributes .= \'href="\' . esc_attr( $item->url ) .\'"\';

        $attributes  = trim( $attributes );
        $title       = apply_filters( \'the_title\', $item->title, $item->ID );
        $item_output = "$args->before<a $attributes>$args->link_before$title</a>"
                        . "$args->link_after$args->after";

        $mycatid = $item->object_id;
        $category = get_category($mycatid);
        $mycatslug = $category->slug;
        $classes = empty( $item->classes ) ? array() : (array) $item->classes;
        $class_names .= in_array("current_page_item",$item->classes) ? \' active\' : \'\';
        $class_names = \' class="staysexy\'. esc_attr( $class_names );
        $output .= $indent . \'
                    <li id="nav-menu-item-\'. $item->ID . \'" class="genre-\'. $mycatslug . \'">\';
        $output .= apply_filters(
            \'walker_nav_menu_start_el\'
            ,   $item_output
            ,   $item
            ,   $depth
            ,   $args
        );
    }
    public function start_lvl( &$output )
    {
        $output .= \'<ul class="sub-menu">\';
    }
    public function end_lvl( &$output )
    {
        $output .= \'</ul>\';
    }
    function end_el( &$output )
    {
        $output .= \'</li>\';
    }
}?>