How to disable a field or make it readonly in Drupal 7

Question

I am trying to disable couple of fields and make them readonly via hook_page_alter(). I was able to do check if user is viewing the page edit section (the form edit)

Answer 1

Like it said in the docs

You can use attributes :

$form['#attributes'] = array('disabled' => TRUE);

Answer 2

It works for text fields^

$form['field_secured_title']['und']['0']['value']['#attributes']['disabled'] = TRUE;