无法创建在WordPress

Question

子菜单两个级别以上我没有经历这样的：https://www.elegantthemes.com/blog/tips-tricks/how-to-create-custom-menu-structures-in-wordpress

我没有按照上面的文章，以创建三级子菜单。但是，在前端Woocommerce（绿色苹果）的产品类别的第三级别没有显示在下拉列表中。

我还读了一个stackoverflow答案，它说它不可能创建三级子菜单。我相信这有一个解决方法。请建议我。

谢谢。

尝试按@ Rafin的回答，

如果全部置于第二级之后第三级，那么就说明了，但是这是不是哪里的应该二级菜单（苹果）的子菜单是。

在后端，全部置于第二级菜单

显示了这样的前端后，

但我需要它来安排这方式：

Answer 1

您可以使用下面沃克类，它扩展WordPress的导航菜单

<?php  
class ods_bootstrap_navwalker extends Walker_Nav_Menu { 

    /** 
    * @see Walker::start_lvl() 
    * @since 3.0.0 
    * 
    * @param string $output Passed by reference. Used to append additional content. 
    * @param int $depth Depth of page. Used for padding. 
    */ 
    public function start_lvl(&$output, $depth = 0, $args = array()) { 
     $indent = str_repeat("\t", $depth); 
     $output .= "\n$indent<div class=\"drop\"><ul role=\"menu\" class=\" dropdown-menu\">\n"; 
    } 

    /** 
    * @see Walker::start_el() 
    * @since 3.0.0 
    * 
    * @param string $output Passed by reference. Used to append additional content. 
    * @param object $item Menu item data object. 
    * @param int $depth Depth of menu item. Used for padding. 
    * @param int $current_page Menu item ID. 
    * @param object $args 
    */ 
    public function start_el(&$output, $item, $depth = 0, $args = array(), $id = 0) { 
     $indent = ($depth) ? str_repeat("\t", $depth) : ''; 

     /** 
     * Dividers, Headers or Disabled 
     * ============================= 
     * Determine whether the item is a Divider, Header, Disabled or regular 
     * menu item. To prevent errors we use the strcasecmp() function to so a 
     * comparison that is not case sensitive. The strcasecmp() function returns 
     * a 0 if the strings are equal. 
     */ 
     if (strcasecmp($item->attr_title, 'divider') == 0 && $depth === 1) { 
      $output .= $indent . '<li role="presentation" class="divider">'; 
     } else if (strcasecmp($item->title, 'divider') == 0 && $depth === 1) { 
      $output .= $indent . '<li role="presentation" class="divider">'; 
     } else if (strcasecmp($item->attr_title, 'dropdown-header') == 0 && $depth === 1) { 
      $output .= $indent . '<li role="presentation" class="dropdown-header">' . esc_attr($item->title); 
     } else if (strcasecmp($item->attr_title, 'disabled') == 0) { 
      $output .= $indent . '<li role="presentation" class="disabled"><a href="#">' . esc_attr($item->title) . '</a>'; 
     } else { 

      $class_names = $value = ''; 

      $classes = empty($item->classes) ? array() : (array) $item->classes; 
      $classes[] = 'scroll menu-item-' . $item->ID; 

      $class_names = join(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item, $args)); 

      if ($args->has_children) 
       $class_names .= ' dropdown'; 

      if (in_array('current-menu-item', $classes)) 
       $class_names .= ' active'; 

      $class_names = $class_names ? ' class="' . esc_attr($class_names) . '"' : ''; 

      $id = apply_filters('nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args); 
      $id = $id ? ' id="' . esc_attr($id) . '"' : ''; 

      $output .= $indent . '<li' . $id . $value . $class_names .'>'; 

      $atts = array(); 
      $atts['title'] = ! empty($item->title) ? $item->title : ''; 
      $atts['target'] = ! empty($item->target) ? $item->target : ''; 
      $atts['rel'] = ! empty($item->xfn)  ? $item->xfn : ''; 
      $atts['class'] = "back-top"; 

      // If item has_children add atts to a. 
      if ($args->has_children && $depth === 0) { 
       $atts['href']   = '#'; 
       $atts['data-toggle'] = 'dropdown'; 
       $atts['class']   = 'dropdown-toggle'; 
       $atts['aria-haspopup'] = 'true'; 
      } else { 
       $atts['href'] = ! empty($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; 

      /* 
      * Glyphicons 
      * =========== 
      * Since the the menu item is NOT a Divider or Header we check the see 
      * if there is a value in the attr_title property. If the attr_title 
      * property is NOT null we apply it as the class name for the glyphicon. 
      */ 
      if (! empty($item->attr_title)) 
       $item_output .= '<a'. $attributes .'><span class="glyphicon ' . esc_attr($item->attr_title) . '"></span>&nbsp;'; 
      else 
       $item_output .= '<a'. $attributes .'>'; 

      $item_output .= $args->link_before . apply_filters('the_title', $item->title, $item->ID) . $args->link_after; 
      $item_output .= ($args->has_children && 0 === $depth) ? ' <span class="icon-play"></span></a>' : '</a>'; 
      $item_output .= $args->after; 

      $output .= apply_filters('walker_nav_menu_start_el', $item_output, $item, $depth, $args); 
     } 
    } 

    /** 
    * Traverse elements to create list from elements. 
    * 
    * Display one element if the element doesn't have any children otherwise, 
    * display the element and its children. Will only traverse up to the max 
    * depth and no ignore elements under that depth. 
    * 
    * This method shouldn't be called directly, use the walk() method instead. 
    * 
    * @see Walker::start_el() 
    * @since 2.5.0 
    * 
    * @param object $element Data object 
    * @param array $children_elements List of elements to continue traversing. 
    * @param int $max_depth Max depth to traverse. 
    * @param int $depth Depth of current element. 
    * @param array $args 
    * @param string $output Passed by reference. Used to append additional content. 
    * @return null Null on failure with no changes to parameters. 
    */ 
    public function display_element($element, &$children_elements, $max_depth, $depth, $args, &$output) { 
     if (! $element) 
      return; 

     $id_field = $this->db_fields['id']; 

     // Display this element. 
     if (is_object($args[0])) 
      $args[0]->has_children = ! empty($children_elements[ $element->$id_field ]); 

     parent::display_element($element, $children_elements, $max_depth, $depth, $args, $output); 
    } 

    /** 
    * Menu Fallback 
    * ============= 
    * If this function is assigned to the ods_nav_menu's fallback_cb variable 
    * and a manu has not been assigned to the theme location in the WordPress 
    * menu manager the function with display nothing to a non-logged in user, 
    * and will add a link to the WordPress menu manager if logged in as an admin. 
    * 
    * @param array $args passed from the ods_nav_menu function. 
    * 
    */ 
    public static function fallback($args) { 
     if (current_user_can('manage_options')) { 

      extract($args); 

      $fb_output = null; 

      if ($container) { 
       $fb_output = '<' . $container; 

       if ($container_id) 
        $fb_output .= ' id="' . $container_id . '"'; 

       if ($container_class) 
        $fb_output .= ' class="' . $container_class . '"'; 

       $fb_output .= '>'; 
      } 

      $fb_output .= '<ul'; 

      if ($menu_id) 
       $fb_output .= ' id="' . $menu_id . '"'; 

      if ($menu_class) 
       $fb_output .= ' class="' . $menu_class . '"'; 

      $fb_output .= '>'; 
      $fb_output .= '<li><a href="' . admin_url('nav-menus.php') . '">Add a menu</a></li>'; 
      $fb_output .= '</ul>'; 

      if ($container) 
       $fb_output .= '</' . $container . '>'; 

      echo $fb_output; 
     } 
    } 
} 

你还可以用

<?php 
        wp_nav_menu(array(
        'menu'    => your_menu_name, 
        'theme_location' => your_menu_location, 
        'depth'    => 3, 
        'container'   => '', 
        'container_class' => '', 
        'container_id'  => 'bs-example-navbar-collapse-1', 
        'menu_class'  => 'navigation', 
        'fallback_cb'  => 'ods_bootstrap_navwalker::fallback', 
        'walker'   => new ods_bootstrap_navwalker()) 
        ); 
       ?> 

显示菜单花点时间https://developer.wordpress.org/reference/classes/walker_nav_menu/