Cant make postal code only required

Question

I am using the adress field module and like to make only the postal code field required. The rest of the fields i like to hide.

The hiding of the fields are no problem however i am having problems with making only the postalcode field required. I can hide the whole field with:

<?php
 function my_form_user_profile_form_alter(&$form, $form_state,  $form_id) {                

  if ($form_id == 'user_profile_form') {

  $form['field_adress']['und'][0]['#required'] = TRUE;
      }
    }
      ?>

but then this is not working

$form['field_adress']['und'][0]['locality_block']['postal_code']['#required'] = TRUE;

What am i missing? Without succes i have tried solutions as: In here and here

Answer 1

You can make the address field not-required and write a custom validate function to check for the postal code. Like this:

<?php
function my_form_user_profile_form_alter(&$form, $form_state,  $form_id) {                
  if ($form_id == 'user_profile_form') {
      $form['field_adress']['und'][0]['#required'] = FALSE;
      array_unshift($form['#validate'], '_my_postal_validate');
  } 
}

function _my_postal_validate(&$form, &$form_state) {
    if (strlen($form_state['values']['field_adress']['und'][0]['postal_code']) < 2) {
        form_set_error('field_address', t('You must enter a postal code'));
    }
}
?>

See form_set_error to set better form errors.

If you support non US addresses (without a postal code), make sure the postal_code is available or you'll get warnings.