How can I implement the multi-level list in drupal7 with theme_item_list()?

Question

Im using drupal 7, I would like to know whether i can use the function theme_item_list() to implement multi-level list items. As below:

Item 1

test
• Item 1.1
• Item 1.2
• Item 1.3

Item 2

• Item 2.1
• Item 2.2
• Item 2.3
  • Item 2.3.1
  • Item 2.3.2
  • Item 2.3.3

Item 3

If possible can anybody help me with an example.

Answer 1

Yes it's possible, if you pass in an array with keys of data and children for each item that has a sub-list, for example:

$items = array(
  array(
    'data' => 'Item 1',
    'children' => array(
      array(
        'data' => 'Item 1.1',
        'children' => array(
          'Item 1.1.1',
          'Item 1.1.2'
        )
      ),
      array(
        'data' => 'Item 1.2',
        'children' => array(
          'Item 1.2.1',
          'Item 1.2.2'
        )
      )
    )
  ),
  array(
    'data' => 'Item 2',
    'children' => array(
      // etc...
    )
  )
);

$output = theme('item_list', array('items' => $items));

The data key represents the contents of the list item, children is an array of list items to render as a separate list within that list item. The function is recursive and can handle any number of levels.