Correctly using hook_form_alter on CCK fields for attributes like #disabled

Applying to one of the CCK wrappers won't work, you need to apply it to the actual Form API element that supports #disabled (http://api.drupal.org/api/file/developer/topics/forms_api_reference.html...)
Meaning the '#type' => 'textfield', 'textarea', 'select'... element

Hi Moonshine,

Where did you put that code?? I call it in hook_form_alter, but doesn´t work!!!

I can´t believe nobody needs this feature before!!!

@Moonshine : hm, of course you're right, elements are not processed yet by the time form_alter runs...
That's a little annoying I guess, not only about #disabled.

This is a difference in D6 -- the CCK fields now use FAPI and get built out in #process. The only thing that happens in form_alter() is to attach the top level, unprocessed, element to the form. This was done to allow widgets to handle their own pre- and post-processing, to make CCK's core multiple value handling easier, and to make it possible to 'nest' elements (like the nodereference field which then in turn builds out either an optionwidgets widget or a text widget).

The top level element is there during form_alter, so you can attach your own #after_build or #pre_render function to the top level of the field in form_alter(), and your custom function will be get the fully-processed form element that can be altered any way you like. I wouldn't use #process, you might still be too early at that point, depending on where and how you use it.

Since CCK widgets now use FAPI, you really need to know a little FAPI to work with them, but it's not really any harder than using form_alter.

Another alternative, if you only want to disable it, would be to do it in a custom theme or preprocess instead of in form_alter. That might be easier, and it might be a more logical place to do it.

Finally I got it working!!

The steps:

1. Add a new callback when the field is "#pre_reder"ing:

function mymodule_elements() {
return array(
'text_textarea' => array( // I need to disable a Text Area field type
'#pre_render' => array('mymodule_field_process'),
),
);
}

2. Treat the field when callback funtion will be called:

function mymodule_field_process($element) {

if ($element['#field_name'] == 'field_disabled' ){ // Change field_disabled with the real name of your field. You can add here any other conditions you want.
$element['value']['#attributes']['disabled'] = 'disabled';
}

return $element;
}

That's all folks!!

thanks for the help!!

The solution from #7 fixed this for me.

I'll admit that this is far beyond my realm of knowledge of FAPI and CCK, but it sure would be nice if we could just form_alter in a #disabled like we do for every other field type.

Spoke a little too soon - if I try to submit fields that I've disabled in that manner I get a validation error:

"Fieldname field is required."

All the same, this seems "fixed" and/or a duplicate of #336355: Unable to add '#attributes' or use '#disabled' = true via hook_form_alter() where I found a similar answer.

Try also setting ['#required'] = FALSE

I thought i'd change this since people search for this on google

Sure, great idea.

See also http://drupal.org/node/357328 in the handbook which documents how this can be achieved.

greggles: that handbook came just on time for me. It is just great when I can be reassured on some ideas.
Thanks !

I just found that someone can patch the script

see http://drupal.org/node/404974

but I still don't know how to implement the function

for me, this worked, i had to pay attention to the groups the fields were in:

<?php
function mymodule_form_alter(&$form, $form_state, $form_id) {
  $form['#after_build'][] = 'mymodule_after_build';
}

function mymodule_after_build($form, &$form_state) {
  // This is for a node reference field:
  $form['field_refref']['nid']['nid']['#value'] = $some_value;
  $form['field_refref']['nid']['nid']['#attributes']['disabled'] = true;
  // This is for an integer field:
  $form['group_something']['field_number'][0]['value']['#value'] += 1;
  return $form;
}
?>