How to add classes to comments?

Question

I've put the following code above print render($content['comments']); in comment-wrapper.tpl.php of our theme to add question or answer class to every comment:

    foreach($content['comments'] as &$c) {
      if(is_array($c) && array_key_exists('#entity_type', $c) && $c['#entity_type'] == 'comment') {
        $uid = $c['comment_body']['#object']->uid;
        $c['#attributes']['class'][] = $uid == 1 ? 'answer' : 'question';
      }
    }

The generated HTML however has no question or answer classes. Please help me to correct the error.

Answer 1

The following code worked for me, put it in your theme's template.php and replace theme with the name of your theme:

function theme_preprocess_comment(&$vars) {
  $element = $vars['elements'];
  $comment = $element['#comment'];

  if(array_key_exists('#entity_type', $element) && $element['#entity_type'] == 'comment') {
    $vars['classes_array'][] = $comment->uid == 1 ? 'answer' : 'question';
  }
}

Although I think the extra checks for entity type is not necessary since this theme is only applied to comments.

Answer 2

I think your ternary statement is off in that code.

I would also suggest an alternative approach. You can use hook_preprocess_comment() in a template.php file or in a custom module. With this you can hook into the comment before it's rendered to the page, run each comment through an logic test and add a class to the entire comment, or add an html chunk before or after the comment's html. See more on hook_preprocess and render arrays.