Question

Background: In Drupal 7, I have created a form with CCK (aka the Field UI). I used the Field group module to create a fieldgroup, but I need it to be conditional, meaning it will only display depending on a previous answer.

Previous research: To create a conditional field, you can use hook_form_alter() to edit the #states attribute like so:

function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'person_info_node_form') {
    // Display 'field_maiden_name' only if married
    $form['field_maiden_name']['#states'] = array(
      'visible' => array(
        ':input[name="field_married[und]"]' => array('value' => 'Yes'),
      ),
    );
  }
}

However, there seems to be no way to use the States API for fieldgroups. One thing to note is that, while fields are stored in $form, fieldgroups are stored in $form['#groups'] as well as in $form['#fieldgroups']. I don’t know how to distinguish between these, and with this in mind, I have tried to apply a #states attribute to a fieldgroup in the same manner as above. However, it only produces server errors.

Question: Is there a way to make a fieldgroup display conditionally using the States API or some alternative approach?

Answer 1

Here’s the simplest solution I came up with. There are essentially 2 parts to this: (1.) programmatically alter the display of the form, and (2.) use the GUI to alter the display of the content.

(1.) First, I used hook_form_alter() to programmatically create the conditional fieldset and add existing fields to it. The code is shown below.

function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'FORM_ID_node_form') {
    // programmatically create a conditional fieldset
    $form['MYFIELDSET'] = array( // do NOT name the same as a 'Field group' fieldset or problems will occur
      '#type' => 'fieldset',
      '#title' => t('Conditional fieldset'),
      '#weight' => intval($form['field_PARENT']['#weight'])+1, // put this fieldset right after it's "parent" field
      '#states' => array(
        'visible' => array(
          ':input[name="field_PARENT[und]"]' => array('value' => 'Yes'), // only show if field_PARENT == 'Yes'
        ),  
      ),  
    );

    // add existing fields (created with the Field UI) to the
    // conditional fieldset
    $fields = array('field_MYFIELD1', 'field_MYFIELD2', 'field_MYFIELD3');
    $form = MYMODULE_addToFieldset($form, 'MYFIELDSET', $fields);
  }
}

/**
 * Adds existing fields to the specified fieldset.
 *
 * @param  array   $form Nested array of form elements that comprise the form.
 * @param  string  $fieldset The machine name of the fieldset.
 * @param  array   $fields An array of the machine names of all fields to
 *                   be included in the fieldset.
 * @return array   $form The updated form.
 */
function MYMODULE_addToFieldSet($form, $fieldset, $fields) {
  foreach($fields as $field) {
    $form[$fieldset][$field] = $form[$field]; // copy existing field into fieldset
    unset($form[$field]); // destroy the original field or duplication will occur
  }

  return $form;
}

(2.) Then I used the Field group module to alter the display of the content. I did this by going to my content type and using the ‘Manage display’ tab to create a field group and add my fields to it. This way, the fields will appear to be apart of the same group on both the form and the saved content.