我的WP主题在描述菜单功能上得到了这些通知

我的代码：

http://www49.zippyshare.com/v/89513423/file.html

/* Discription Navigation Menu, Credit to Christian Kriesi  */

class description_walker extends Walker_Nav_Menu

{

      function start_el(&$output, $item, $depth, $args)
      {
           global $wp_query;
           $indent = ( $depth ) ? str_repeat( "\\t", $depth ) : \'\';

           $class_names = $value = \'\';

           $classes = empty( $item->classes ) ? array() : (array) $item->classes;

           $class_names = join( \' \', apply_filters( \'nav_menu_css_class\', array_filter( $classes ), $item ) );
           $class_names = \' class="\'. esc_attr( $class_names ) . \'"\';

           $output .= $indent . \'<li id="menu-item-\'. $item->ID . \'"\' . $value . $class_names .\'>\';

           $attributes  = ! empty( $item->attr_title ) ? \' title="\'  . esc_attr( $item->attr_title ) .\'"\' : \'\';
           $attributes .= ! empty( $item->target )     ? \' target="\' . esc_attr( $item->target     ) .\'"\' : \'\';
           $attributes .= ! empty( $item->xfn )        ? \' rel="\'    . esc_attr( $item->xfn        ) .\'"\' : \'\';
           $attributes .= ! empty( $item->url )        ? \' href="\'   . esc_attr( $item->url        ) .\'"\' : \'\';

           $prepend = \'<span>\';
           $append = \'</span>\';
           $description  = ! empty( $item->description ) ? \'<span class="nav-sec">\'.esc_attr( $item->description ).\'</span>\' : \'\';

           if($depth != 0)
           {
                $description = $append = $prepend = "";
           }

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

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

我的wp\\U nav\\U菜单：

  $header_menu_args = array(    
      \'theme_location\' => \'main_menu\',                                
      \'container_class\' => \'menu\',
      \'container_id\' => \'dropdown\',
      \'menu_id\' => \'\', 
      \'menu_class\' => \'sf-menu\',
      \'echo\' => true,
      \'before\' => \'\',
      \'after\' => \'\',
      \'link_before\' => \'\',
      \'link_after\' => \'\',
      \'depth\' => 0,
      \'walker\' => new description_walker()                                
  );
  wp_nav_menu( $header_menu_args );
  dropdown_menu( $header_menu_args );

问题出现在第44、46、47、49行的非对象属性中。

http://multipixels.net/files/theme_function_debug.png

请帮我弄清楚。

向你问好，德克尼奥