可能不是你想要的，但你可以看看Bootstrap Nav Walker implementation.

在documentation, 还有一个例子manually calling your own walker 类，如果您还没有这样做的话，可能值得一读。

class Walker_Quickstart_Menu extends Walker {

    // Tell Walker where to inherit it\'s parent and id values
    var $db_fields = array(
        \'parent\' => \'menu_item_parent\', 
        \'id\'     => \'db_id\' 
    );

    /**
     * At the start of each element, output a <li> and <a> tag structure.
     * 
     * Note: Menu objects include url and title properties, so we will use those.
     */
    function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
        $output .= sprintf( "\\n<li><a href=\'%s\'%s>%s</a></li>\\n",
            $item->url,
            ( $item->object_id === get_the_ID() ) ? \' class="current"\' : \'\',
            $item->title
        );
    }
}

// 1. Fetch the menu (we\'ll assume it has an id of 2)...
$menu = wp_get_nav_menu_object(2);

// 2. Create an empty $menu_items array
$menu_items = array();

// 3. Get menu objects (this is our tree structure)
if ( $menu && ! is_wp_error($menu) && empty($menu_items) ) {
    $menu_items = wp_get_nav_menu_items( $menu );
}

// 4. Create a new instance of our walker...
$walk = new Walker_Quickstart_Menu();

// 5. Walk the tree and render the returned output as a one-dimensional array
print_r( $walk->walk( $menu_items, -1 ) );