How to theme Nice Menus as table-based menus

NOTE: this is based on the 6.x-1.x version of Nice Menus. The 2.x version is quite different, so this example would need to be modified.

Wherever Drupal's theme() function is called, there is an opening to change the default theming. So for Nice Menus, just check out the source code of this module where we have these two functions:

function theme_nice_menu($id, $menu_name, $mlid, $direction = 'right', $menu = NULL)

and

function theme_nice_menu($id, $menu_name, $mlid, $direction = 'right', $menu = NULL)

We'll use them as our starting point. In whatever theme you're working on there's a template.php file designed specially for this kind of purpose. Open it up and insert the following two code segments:

/*
  NOTE: BEFORE YOU ACTUALLY DO THIS, PLEASE CLEAR ALL CACHES FROM YOUR DRUPAL SITE
  This is the point when Nice Menus renders a fully built tree menu to the $output variable
  We change it here to be wrapped inside a table instead of UL elements
*/
function YOURTHEMENAME_nice_menu($id, $menu_name, $mlid, $direction = 'right', $menu = NULL) {
  $output = array();
  if ($menu_tree = theme('nice_menu_tree', $menu_name, $mlid, $menu)) {
    if ($menu_tree['content']) {
      $output['content'] = '<table width="100%" class="site-menu"><tr>' .$menu_tree['content'] .'</tr></table>'."\n";
      $output['subject'] = $menu_tree['subject'];
    }
  }
  return $output;
}
}

The consequent theme function that actually builds the menu tree:

function YOURTHEMENAME_nice_menu_build($menu) {
  $output = '';
  global $is_child;
  foreach ($menu as $menu_item) {
    $mlid = $menu_item['link']['mlid'];
    // Check to see if it is a visible menu item.
    if ($menu_item['link']['hidden'] == 0) {
      // Build class name based on menu path e.g. to give each menu item individual style. Strip funny symbols.
      $clean_path = str_replace(array('http://', '<', '>', '&', '=', '?', ':'), '', $menu_item['link']['href']);
      // Convert slashes to dashes.
      $clean_path = str_replace('/', '-', $clean_path);
      $current_node = str_replace('node-', '', $clean_path);
      $path_class = 'menu-path-'. $clean_path;
      if ($current_node == $GLOBALS['active_node']) {
          $path_class.= ' active-content';
      }
      // If it has children build a nice little tree under it.
      if ((!empty($menu_item['link']['has_children'])) && (!empty($menu_item['below']))) {
        $is_child = true;
        // Keep passing children into the function 'til we get them all.
        $children = theme('nice_menu_build', $menu_item['below']);
        // Set the class to parent only of children are displayed.
        $parent_class = $children ? 'menuparent ' : '';
        if (isset($parent_class)):
          $output .= '<td id="menu-'. $mlid .'" class="'. $parent_class . $path_class .'">'. theme('menu_item_link', $menu_item['link']);
        else:
          $output .= '<li id="menu-'. $mlid .'" class="'. $parent_class . $path_class .'">'. theme('menu_item_link', $menu_item['link']);
        endif;
        // Build the child UL only if there is a child menu
        if ($children) {
          $output .= '<ul>';
          $output .= $children;
          $output .= "</ul>\n";
        }
        /* Notice that we have used <td> if we find a parent class otherwise it goes into <LI> elements. Here's why: All the parent menu items will be rendered inside table cells, so our idea is to create a menu system that can resize proportionally and horizontally to the browser's full width, the subsequent child elements can be placed into <UL><LI> elements which can be themed easily */
        if (isset($parent_class)):
          $output .= "</td>";
          //Adds some extra separators after each td
          $output .= '<td><span class="sep1"></span></td>'."\n";
        else:
          $output .= "</li>\n";
        endif;
      }
      else {
        if ($is_child == false) {
          $output .= '<td id="menu-'. $mlid .'" class="'. $path_class .'">'. theme('menu_item_link', $menu_item['link']) .'</td>'."\n";
          //Adds some extra separators after each td
          $output .= '<td><span class="sep1"></span></td>'."\n";
        }
        else
        {
          $output .= '<li id="menu-'. $mlid .'" class="'. $path_class .'">'. theme('menu_item_link', $menu_item['link']) .'</li>'."\n";
        }
      }
    }
  }
  $is_child = false;
  return $output;
}

And there you have it. The output will be a table-based menu. To read the full article with code and examples, see:

http://www.ravendevelopers.com/blog/2008/12/how-theme-nice-menus-table-b...