WordPress 获取顶级菜单项标题

Question

我正在开发一个WP主题，我想要的是当前顶级项目的侧面导航。

• 菜单项
  • 子菜单项
    • 子菜单项
    • 子菜单项
    • 子菜单项
  • 子菜单项
    • 子菜单项
    • 子菜单项
    • 子菜单项
  • 子菜单项
    • 子菜单项
    • 子菜单项
    • 子菜单项

即下面的代码在侧边栏上可见，除了"菜单项（顶部父项）"。你知道如何实现这一点吗？

// add hook
add_filter( 'wp_nav_menu_objects', 'my_wp_nav_menu_objects_sub_menu', 10, 2 );
// filter_hook function to react on sub_menu flag
function my_wp_nav_menu_objects_sub_menu( $sorted_menu_items, $args ) {
  if ( isset( $args->sub_menu ) ) {
    $root_id = 0;
    // find the current menu item
    foreach ( $sorted_menu_items as $menu_item ) {
      if ( $menu_item->current ) {
        // set the root id based on whether the current menu item has a parent or not
        $root_id = ( $menu_item->menu_item_parent ) ? $menu_item->menu_item_parent : $menu_item->ID;
        break;
      }
    }
    // find the top level parent
    if ( ! isset( $args->direct_parent ) ) {
      $prev_root_id = $root_id;
      while ( $prev_root_id != 0 ) {
        foreach ( $sorted_menu_items as $menu_item ) {
          if ( $menu_item->ID == $prev_root_id ) {
            $prev_root_id = $menu_item->menu_item_parent;
            // don't set the root_id to 0 if we've reached the top of the menu
            if ( $prev_root_id != 0 ) $root_id = $menu_item->menu_item_parent;
            break;
          } 
        }
      }
    }
    $menu_item_parents = array();
    foreach ( $sorted_menu_items as $key => $item ) {
      // init menu_item_parents
      if ( $item->ID == $root_id ) $menu_item_parents[] = $item->ID;
      if ( in_array( $item->menu_item_parent, $menu_item_parents ) ) {
        // part of sub-tree: keep!
        $menu_item_parents[] = $item->ID;
      } else if ( ! ( isset( $args->show_parent ) && in_array( $item->ID, $menu_item_parents ) ) ) {
        // not part of sub-tree: away with it!
        unset( $sorted_menu_items[$key] );
      }
    } 
    return $sorted_menu_items;
  } else {
    return $sorted_menu_items;
  }
}

跟 回显$root_id;我能够获取根菜单项 ID，但我想显示标题。

这是我在侧边栏中的代码

<section class="widget widget_navbar">
  <?php
  if (has_nav_menu('primary_navigation')) :
    wp_nav_menu([
        'theme_location' => 'primary_navigation', 
         'sub_menu'       => true,
    ]);
  endif;
  ?>
</section>

Answer 1

这个过滤器的作者——克里斯蒂安·瓦尔加——在这里有说明：https://gist.github.com/levymetal/5547605#file-show_parent-php。原始博客文章在这里： https://christianvarga.com/how-to-get-submenu-items-from-a-wordpress-menu-based-on-parent-or-sibling/

wp_nav_menu( array(
  'theme_location' => 'primary',
  'sub_menu'       => true,
  'show_parent'    => true // this shows the parent
) );