This is the code I’m using, it’s a custom nav walker for BootStrap but you could easily adapt it to your own. By the way, you could copy & paste my nav walker and be sure to change this line:
$class_names .= ' dropdown';
to
$class_names .= ' sub-menu';
Hope this helps.
/**
* Custom Bootstrap Nav Walker
*/
class macho_bootstrap_walker 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<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[] = '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 : '';
$atts['custom'] = !empty($item->custom) ? $item->custom : '';
// If item has_children add atts to a.
if ($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> ';
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="caret"></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 wp_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 $args passed from the wp_nav_menu function.
*
*/
public static function fallback($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;
}
}
}