checklist_ff.module

<?php

/**
 * @file
 * Provides a checklist field formatter for list field types.
 */

/**
 * Implements hook_field_formatter_info().
 */
function checklist_ff_field_formatter_info() {
  return array(
    'checklist' => array(
      'label' => t('Displays items as checked or unchecked.'),
      'field types' => array('list_text', 'list_float', 'list_integer'),
      'settings' => array(
        'check' => 'x',
        'show_none_selected' => TRUE,
      ),
    ),
  );
}

/**
 * Implements hook_field_formatter_settings_form().
 */
function checklist_ff_field_formatter_settings_form($field, $instance, $view_mode, $form, &$form_state) {
  $display = $instance['display'][$view_mode];
  $settings = $display['settings'];
  $element = array();

  switch ($display['type']) {
    case 'checklist':
      $element['check'] = array(
        '#type' => 'textfield',
        '#title' => t('Check mark'),
        '#description' => t('Symbol displayed to indicate a checked item.'),
        '#default_value' => empty($settings['check']) ? 'x' : $settings['check'],
      );
      $element['show_none_selected'] = array(
        '#type' => 'checkbox',
        '#title' => t('Show if empty'),
        '#description' => t('Show list even if no items are selected.'),
        '#default_value' => empty($settings['show_none_selected']) ? 0 : $settings['show_none_selected'],
      );
      break;
  }

  return $element;
}

/**
 * Implements hook_field_formatter_settings_summary().
 */
function checklist_ff_field_formatter_settings_summary($field, $instance, $view_mode) {
  $display = $instance['display'][$view_mode];
  $settings = $display['settings'];
  $summary = array();

  switch ($display['type']) {
    case 'checklist':
      $summary[] = t('Check mark') . ': ' . $settings['check'];
      $summary[] = t('Show if empty') . ': ' . ($settings['show_none_selected'] == 1 ? 'yes' : 'no');
    break;
  }

  return implode('<br />', $summary) . '<br />';
}

/**
 * Implements hook_field_formatter_view().
 */
function checklist_ff_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $element = array();
  switch ($display['type']) {
    case 'checklist':
      if (function_exists('i18n_field_type_info') && ($translate = i18n_field_type_info($field['type'], 'translate_options'))) {
        $options = $translate($field);
      } else {
        $options = list_allowed_values($field);
      }
      foreach ($options as $key => $label) {
        $checklist[$key] = array('data' => $label);
      }
      $i = 0;
      if (count($items) > 0) {
        foreach ($items as $item) {
          $label = $checklist[$item['value']]['data'];
          $checked = '<span>' . check_plain($display['settings']['check']) . '</span> ' . $label;
          $checklist[$item['value']]['data'] = $checked;
          $checklist[$item['value']]['class'] = array('checked');
          $i++;
        }
      }

      if ($i == 0) {
        $checklist_class = 'checked-none';
      } elseif ($i == count($checklist)) {
        $checklist_class = 'checked-all';
      } else {
        $checklist_class = 'checked-' . $i;
      }

      $variables = array(
        'items' => $checklist,
        'title' => '',
        'type' => 'ul',
        'attributes' => array('class' => array('checklist', $checklist_class)),
      );
      $markup = theme('item_list', $variables);
      $element[] = array(
        '#markup' => $markup,
      );
      break;
  }
  return $element;
}

/**
 * Implements hook_field_attach_view_alter().
 *
 * Overrides field view to show full list, even if no items are selected.
 */
function checklist_ff_field_attach_view_alter(&$output, $context) {
  // Load all instances of the fields for the entity.
  if (isset($context['entity_type']) && isset($context['entity']->type)) {
    $instances = _field_invoke_get_instances($context['entity_type'], $context['entity']->type, array('default' => TRUE, 'deleted' => FALSE));
    foreach ($instances as $field_name => $instance) {
      // Set content for fields that are empty.
      // substituting 'default' for $context['view_mode']
      if (empty($context['entity']->{$field_name})) {
        $display = field_get_display($instance, $context['view_mode'], $context['entity']);

        // Do not add field that is hidden in current display.
        if ($display['type'] == 'hidden') {
          continue;
        }

        if ($display['type'] == 'checklist' && $display['settings']['show_none_selected'] == TRUE) {
          // Load field settings.
          $field = field_info_field($field_name);

          // Get field options
          $element = checklist_ff_field_formatter_view($context['entity_type'], $context['entity'], $field, $instance, NULL, array(), $display);

          // Set output for field.
          $output[$field_name] = array(
            '#theme' => 'field',
            '#title' => $instance['label'],
            '#label_display' => $display['label'],
            '#field_type' => $field['type'],
            '#field_name' => $field_name,
            '#bundle' => $context['entity']->type,
            '#object' => $context['entity'],
            '#items' => array(''),
            '#entity_type' => $context['entity_type'],
            '#weight' => $display['weight'],
            $element[0],
          );

        } else {
          //still getting field label printing, not sure why
          unset($output[$field_name]);
        }
      }
    }
  }
}