Wordpress wp_nav_menu walker: dynamic before content

Question

I build a navigation within a wordpress blog. the items are displayed like this:

The icon is applied by using the bootstrap classes glyhicon-glyphiconname. I add the classes dynamically. The php code for that:

function add_specific_menu_location_atts( $atts, $item, $args ) {
     // check if the item is in the primary menu
     if( $args->theme_location == 'directentries' ) {
       foreach($item as $key => $value) {
           if($key == 'title') {
             $catIcon = setCatIcon($value);
           }
       }
       // add the desired attributes:
       $atts['class'] = 'btn btn-primary btn-lg glyphicon glyphicon-'.$catIcon;
     }
     return $atts;
 }
 add_filter( 'nav_menu_link_attributes', 'add_specific_menu_location_atts', 10, 3 );

$args = array(
        'theme_location' => 'directentries',
        'depth'      => 1,
        'container'  => false,
        'menu_class'     => 'nav',
        'link_before'  => '<br>', 
        //'link_before'  => 'span class"glyphicon"',
        'walker'     => ''
    );
    wp_nav_menu($args);

The problem here is, that the font of the link text is (of course) glyhicon, otherwise the icon would not apply to the link. So: The correct way would be to apply a span using the link-before parameter when initialising the menu. But I need to apply my dynamic classname to the span then. I think I could access the link_before param within my filter class using the $args parameter..

The current markup is this: And I need it to be linke this: Does anyone have an idea how to apply a span and vary the classes?

.

Answer 1

Although a custom Nav Walker class might be a good (better?) solution as @Trix suggested, I want to answer the question how to apply a span using my filter. This code did it:

function add_specific_menu_location_atts( $atts, $item, $args ) {
     if( $args->theme_location == 'directentries' ) {
       foreach($item as $key => $value) {
           if($key == 'title') {
             $catIcon = setCatIcon($value);
           }
       }
       foreach($args as $key => $value) {
           if($key == 'link_before') {
              $args->$key = '<span class="glyphicon glyphicon-'.$catIcon.'"></span><br>';
           }
       }
       // add the desired attributes:
       $atts['class'] = 'btn btn-primary btn-lg'; 
     }
     return $atts;
 }
 add_filter( 'nav_menu_link_attributes', 'add_specific_menu_location_atts', 10, 3 );