wp_nav_menu add class to child item with sub child

Question

I need your help, am trying to add class dropdown-submenu to a <li> element which has children. Not sure if I was clear enough, so here is an example:

   |-Home (Parent Item)
   |-Services (Parent Item) *class='dropdown'*
       |-Orthodontics (Child Item) *** class="dropdown-submenu" ***
          |-Invisalign (Sub Child Item)
          |-Inman Aligner (Sub Child Item)

The HTML format is:

                        <!-- Services -->
                <li class="dropdown active">
                <a href="javascript:void(0);" class="dropdown-toggle" data-toggle="dropdown">
                        Services
                    </a>
                    <ul class="dropdown-menu">
                        <!-- Service Orthodontics -->
                        <li class="dropdown-submenu active">
                            <a href="javascript:void(0);">Orthodontics</a>
                            <ul class="dropdown-menu">
                                <li><a href="invisalign.html">Invisalign</a></li>
                                <li><a href="inman_aligner.html">Inman Aligner</a></li>
                            </ul>
                        </li>
                        <!-- End Service Orthodontics -->

My walker-class gives all <li> elements which has <ul> class dropdown. It simply look if the element has child and if true it set the class name to dropdown. Here is the code of walker.php

        class Main_Walker_Nav_Menu extends Walker_Nav_Menu {

function start_lvl( &$output, $depth ){ //ul
    $indent = str_repeat("\t",$depth);
    $submenu = ($depth > 0) ? ' dropdown-menu' : '';
    $output .= "\n$indent<ul class=\"dropdown-menu$submenu depth_$depth\">\n";  }


function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ){ //li a span

    $indent = ( $depth ) ? str_repeat("\t",$depth) : '';

    $li_attributes = '';
    $class_names = $value = '';

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

    $classes[] = ($args->walker->has_children) ? 'dropdown' : '';
    $classes[] = ($item->current || $item->current_item_anchestor) ? 'active' : '';
    $classes[] = 'menu-item-' . $item->ID;
    if( $depth && $args->walker->has_children ){
        $classes[] = 'dropdown-submenu';
    }

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

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

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

    $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) . '"' : '';

    $attributes .= ( $args->walker->has_children ) ? ' class="dropdown-toggle" data-toggle="dropdown"' : '';

    $item_output = $args->before;
    $item_output .= '<a' . $attributes . '>';
    $item_output .= $args->link_before . apply_filters( 'the_title', $item->title, $item->ID ) . $args->link_after;
    $item_output .= ( $depth == 0 && $args->walker->has_children ) ? '</a>' : '</a>';
    $item_output .= $args->after;

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

}

Thanks in advance.

Answer 1

I have not tested this but it looks like you aren't testing for $depth the way you need to be.

This block:

$classes[] = ($args->walker->has_children) ? 'dropdown' : '';
$classes[] = ($item->current || $item->current_item_anchestor) ? 'active' : '';
$classes[] = 'menu-item-' . $item->ID;
if( $depth && $args->walker->has_children ){
    $classes[] = 'dropdown-submenu';
}

Should be something like:

if ($args->walker->has_children) {
  if (0 === $depth) {
    $classes[] = 'dropdown';
  } else {
    $classes[] = 'dropdown-submenu';
  }
} 
$classes[] = ($item->current || $item->current_item_anchestor) ? 'active' : '';
$classes[] = 'menu-item-' . $item->ID;

Answer 2

when we say $args->walker->has_children means $depth == 1 you can add dropdown-submenu as below

if( $depth == 1 ){
    $classes[] = 'dropdown-submenu';
}

Answer 3

I think you should try the nav_menu_submenu_css_class filter. This worked for me and it's really simple.

add_filter('nav_menu_submenu_css_class','some_function', 10, 3 );
function some_function( $classes, $args, $depth ){

    foreach ( $classes as $key => $class ) {
        if ( $class == 'sub-menu' && $depth == 0) {
            $classes[ $key ] = 'your-class';
        }elseif($class == 'sub-menu' && $depth == 1){
            $classes[ $key ] = 'your-class';
        }
    } 
    return $classes;
}