Print the secondary links as expanded in a template file

Question

I'm trying to print the secondary links for the main menu as expanded in my template node--products.tpl.php. In my menu I have three levels.

-Products

--Product category

---Product

-Another menu link

The result should be a menu with all product categories with the child items. I don't want to print the root level in the menu; I only want the secondary level, and its children to appear.

I have tried to print the secondary menu like this, but the child items doesn't appear. Any help appreciated.

$secondary_menu = theme_get_setting('toggle_secondary_menu') ? menu_secondary_menu() : array();
print theme('links__system_main_menu', array(
    'links' => $secondary_menu,
    'attributes' => array(
    'id' => 'main-menu-links',
    'class' => array('links', 'clearfix'),
  ),
    'heading' => array(
    'text' => t('Main menu'),
    'level' => 'h2',
    'class' => array('element-invisible'),
  ),
));

Answer 1

In your themes template.php add the following:

function THEMENAME_preprocess_page(&$variables) {

  // Get the entire menu tree (you can replace this string with any menu you want)
  $main_menu_tree = menu_tree_all_data('main-menu');

  // Generate structure for rendering the menu.
  $menu = menu_tree_output($tree);

  // Replace the $menu array with the #below array beloning to the first top 
  // level menu item.
  $menu = $menu[key($menu)]['#below'];

  // Add $main_menu_no_top as a variable to use in our theme
  $variables['main_menu_no_top'] = $menu;
}

Then, in page.tpl.php, you can just use:

<?php print render($main_menu_no_top); ?>