select_or_other_taxonomy.module

<?php

/**
 * Select (or other) taxonomy module, for Drupal 7.
 *
 */

/**
 * Implements hook_field_widget_info
 */

function select_or_other_taxonomy_field_widget_info() {
  $settings = array(
    'available_options' => '',
    'available_options_php' => '',
    'markup_available_options_php' => t('&lt;none&gt;'),
    'other' => t('Other'),
    'other_unknown_defaults' => 'other',
  );
  return array(
    'select_or_other' => array(
      'label' => t('Select (or other) list'),
      'field types' => array('taxonomy_term_reference'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
        'default value' => FIELD_BEHAVIOR_DEFAULT,
      ),
      'settings' => $settings,
    ),
    'select_or_other_buttons' => array(
      'label' => t('Select (or other) check boxes/radio buttons'),
      'field types' => array('taxonomy_term_reference'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
        'default value' => FIELD_BEHAVIOR_DEFAULT,
      ),
      'settings' => $settings,
    ),
    'select_or_other_hierarchy' => array(
      'label' => t('Select (or other) hierarchical list'),
      'field types' => array('taxonomy_term_reference'),
      'behaviors' => array(
        'multiple values' => FIELD_BEHAVIOR_CUSTOM,
        'default value' => FIELD_BEHAVIOR_DEFAULT,
      ),
      'settings' => $settings,
    ),
  );
}

/**
 * Implements hook_field_widget_form
 */

function select_or_other_taxonomy_field_widget_form( &$form, &$form_state, $field,
  $instance, $langcode, $items, $delta, $element) {

  $element = array(
    '#type' => 'select_or_other',
    '#title' => isset($instance['label']) ? $instance['label'] : NULL,
    '#other' =>
      isset($instance['widget']['settings']['other']) ?
      $instance['widget']['settings']['other'] : t('Other'),
    '#default_value' => !empty($items[$delta]) ? $items[$delta] : NULL,
    '#options' => select_or_other_taxonomy_get_options($field, $instance['widget']['type'], $items),
    '#description' => isset($instance['description']) ? $instance['description'] : '',
    '#multiple' => $field['cardinality'] == 1 ? FALSE : $field['cardinality'],
    '#required' => $instance['required'],
    '#other_delimiter' => FALSE,
    '#other_unknown_defaults' =>
      isset($instance['widget']['settings']['other_unknown_defaults']) ?
      $instance['widget']['settings']['other_unknown_defaults'] : 'other',
    '#element_validate' => array('select_or_other_taxonomy_field_widget_validate'),
    '#field_widget' => $instance['widget']['type'],
  );

  // Set select types.
  switch ($instance['widget']['type']) {
    case 'select_or_other':
      $element['#select_type'] = 'select';
      break;
    case 'select_or_other_buttons':
      $element['#select_type'] = $field['cardinality'] == 1 ? 'radios' : 'checkboxes';
      break;
    case 'select_or_other_hierarchy':
      $element['#select_type'] = 'select';
      break;
  }

  // In situations where we handle our own multiples (checkboxes and multiple selects),
  // set defaults differently.
  if ($element['#multiple']) {
    $element['#default_value'] = array();
    foreach ($items as $delta => $item) {
      $element['#default_value'][$delta] = $item['tid'];
    }
  }

  return $element;
}

/**
 * Utility function to create the form options for a taxonomy item.
 */

function select_or_other_taxonomy_get_options($field, $widget_type, $items) {
  // get the vocabulary associated with this field (there's probably only one, but who knows...)
  $vocabularies = array();
  foreach ($field['settings']['allowed_values'] as $tree) {
    if ( $vocabulary = taxonomy_vocabulary_machine_name_load($tree['vocabulary']) ) {
      $vocabularies[] = $vocabulary->vid;
    }
  }

  // get the taxonomy term ids for our vocabulary (we'll just use the first one in the list)
  // the new drupal 7 method for getting taxonomy terms is via entityfieldquery.
  $query = new EntityFieldQuery;
  $result = $query->entityCondition('entity_type', 'taxonomy_term')
    ->propertyCondition('vid', $vocabularies[0])
    ->execute();

  // load the taxonomy terms
  $tids = array();
  foreach ($result['taxonomy_term'] as $tid) {
    $tids[] = $tid->tid;
  }
  $taxonomy_terms = taxonomy_get_tree($vocabulary->vid);


  $items_ids= array();
  foreach ($items as $item) {
    $items_ids[] = $item['tid'];
  }
  // create the options array
  $options = array();

  if ($widget_type == 'select_or_other_hierarchy') {
    foreach ($taxonomy_terms as $term) {
      if(!(substr($term->name, 0, strlen(t('Other')))==t('Other')) || in_array($term->tid, $items_ids)) {
        $options[$term->tid] = str_repeat('-', $term->depth) . ' ' . $term->name;
      }
    }
  } else {
    foreach ($taxonomy_terms as $term) {
      if(!(substr($term->name, 0, strlen(t('Other')))==t('Other')) || in_array($term->tid, $items_ids)) {
        $options[$term->tid] = $term->name;
      }
    }
  }

  return $options;
}

/**
 * Validation function for these form elements.
 *
 * We register this function as the validation callback in the hook above.
 * Does some error checking and sets the form value in the correct place in the form array.
 *
 */

function select_or_other_taxonomy_field_widget_validate($element, &$form_state) {

  $field_info = field_info_field($element['#field_name']);
  $other_selected = FALSE;
  $values = array();

  if (is_array($element['select']['#value'])) {
    // This is a multiselect. assoc arrays
    $value = $element['select']['#value'];

    if (in_array('select_or_other', $value)) {
      $other_selected = TRUE;
      $value = $element['select']['#value'];
      unset($value['select_or_other']);
    }

    foreach ($value as $v) {
      if ($v) {
        $values[] = array('tid' => $v);
      }
    }

    if ($other_selected) {
      if ($other_value = select_or_other_taxonomy_get_other_value($element, $field_info) ) {
        $values[] = $other_value;
      }
    }
  }
  else {
    // This is a single select

    if ($element['select']['#value'] == 'select_or_other') {
      $values[] = select_or_other_taxonomy_get_other_value($element, $field_info);
    } else {
      $values[] = array( 'tid' => $element['select']['#value'] );
    }
  }

  if ($element['#multiple'] >= 2 && count($values) > $element['#multiple']) {
    form_error($element['select'], t('%name: this field cannot hold more than @count values.',
      array('%name' => t($element['select']['#title']), '@count' => $element['#multiple'])) );
  }

  $value = $values;
  form_set_value($element, $value, $form_state);
}

/**
 * Reformats the form['other'] field in the array format needed to create a new term. Does error checking.
 */

function select_or_other_taxonomy_get_other_value($element, $form_info) {
  $value = $element['other']['#value'];
  // First do some error handling
  if (!$value) {
    form_error($element['other'], t('%name: @title is required',
      array('%name' => t($element['select']['#title']), '@title' => $element['#other'])));
    return FALSE;
  }
  elseif ( drupal_strlen($value) > 255 ) {
    form_error($element['other'], t('%name: @title may not be longer than 255 characters.',
      array('%name' => t($element['select']['#title']), '@title' => $element['#other'])));
    return FALSE;
  }
  else {
    $vocabulary_name = $form_info['settings']['allowed_values'][0]['vocabulary'];
    $vid = taxonomy_vocabulary_machine_name_load($vocabulary_name)->vid;

    return array(
      'tid' => 'autocreate',
      'vid' => $vid,
      'name' => t('Other') . ': ' . $element['other']['#value'],
      'vocabulary_machine_name' => $vocabulary_name
    );
  }
}