Recursive dropdown menu not showing correctly on Bootstrap Codeigniter - php

Question

I have issues displaying a dropdown menu generated by a recursive function using a database. The parents are shown correctly below the items, but not as nav items, but just as a basic list.
Here's the image with how it actually looks:
And here's how it SHOULD look:
Some relevant code:
Model:
<?php
class New_menu_model extends CI_Model {
function get_domains() {
$result = $this->db->get ( 'domenii' );
return $result->result_array();
}
}
function recursive($parent, $result) {
$has_children = false;
foreach ( $result as $key => $value ) {
if ($value ['parent'] == $parent) {
if ($has_children === false && $parent) {
$has_children = true;
echo '<ul>' . "\n" ;
}
echo '<li>' . "\n";
echo '' . $value ['nume_domeniu'] . '' . " \n";
echo "\n";
recursive ( $key + 1, $result );
echo "</li>\n";
}
}
if ($has_children === true && $parent)
echo "</ul>\n";
}
?>
View:
<li class="dropdown"><?php echo recursive(0, $menu); ?></li>
Thanks!

Answer 1

It should be something like:
<li class="dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">
Dropdown <span class="caret"></span>
</a>
<ul class="dropdown-menu">
<?php echo recursive(0, $menu); ?>
</ul>
</li>
...and check echo '<ul>' . "\n" ; , it could be echo '<ul class="dropdown-menu">' . "\n" ; so the code should be:
<li class="dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">
Dropdown <span class="caret"></span>
</a>
<?php echo recursive(0, $menu); ?>
</li>