Extra field with wrappers sample

gistfile1.php

<?php

/**
 * Helper to prepare field renderable array for views extra fields.
 */
function _feature_commons_extra_field_view($field_name, $title, $entity, $view_mode, $langcode, $field_content, $access = TRUE, $entity_type = 'node') {
  if (empty($field_content)) {
    return '';
  }

  list($etid, $vid, $bundle) = entity_extract_ids($entity_type, $entity);
  $field = array(
    '#theme' => 'field',
    '#label_display' => empty($title) ? 'hidden' : 'above',
    '#view_mode' => $view_mode,
    '#language' => $langcode,

    '#entity_type' => $entity_type,
    '#bundle' => $bundle,
    '#entity' => $entity,

    '#field_name' => 'ef_' . $field_name,
    '#field_type' => 'extra_field',
    '#field_translatable' => FALSE,
    '#object' => $entity,
    '#formatter' => NULL,

    '#title' => $title,
    '#access' => $access,
    '#items' => array(
      0 => array(
        'value' => $field_content,
        'format' => NULL,
        'safe_value' => $field_content,
      ),
    ),
    0 => array(
      '#markup' => $field_content,
    ),
  );

  if ($entity_type == 'node') {
    $field['#node'] = $entity;
  }
  elseif ($entity_type == 'user') {
    $field['#account'] = $entity;
  }

  if (is_array($field_content)) {
    if (key($field_content) !== 0) {
      $field_content = array($field_content);
    }
    foreach ($field_content as $delta => $element) {
      $field[$delta] = $element;
      $field['#items'][$delta]['value'] = $field['#items'][$delta]['safe_value'] = drupal_render($element);
    }
  }

  return $field;
}



/**
 * Implements hook_node_view().
 */
function feature_content_projects_node_view($node, $view_mode, $langcode) {
  if ($node->type == 'project') {
    $settings = field_extra_fields_get_display('node', $node->type, $view_mode);

    if (!empty($settings['project_builder_logo']['visible'])) {
      // Get the Builder's picture
      $data = $wrapper->og_builder_ref->field_picture->value();
      $field_content = theme('image_style', array(
        'style_name' => 'project_builder',
        'path' => $data['uri'],
      ));
      $field_content = l($field_content, 'node/' . $wrapper->og_builder_ref->nid->value(), array('html' => TRUE));
      $node->content['project_builder_logo'] = _feature_commons_extra_field_view('project_builder_logo', '', $node, $view_mode, $langcode, $field_content);
    }
    if (!empty($settings['project_manager']['visible'])) {
      $manager = _feature_commons_group_get_manager('node', $node->type, $node->nid);
      if (!empty($manager)) {
        $elements = user_view($manager, 'include', $langcode);
        $field_content = drupal_render($elements);
      }
      else {
        $nid = reset(entity_get_id_by_uuid('node', array('4ae0b9cf-afdf-4f6b-b858-8222c1bd9d8b')));
        $field_content = l('Devenir Responsable de ce Programme', 'node/' . $nid, array('query' => array('gid' => $node->nid)));
      }
      $node->content['project_manager'] = _feature_commons_extra_field_view('project_manager', '', $node, $view_mode, $langcode, $field_content);
    }
    if (!empty($settings['project_team_button']['visible'])) {
      $field_content = l('Voir l\'équipe', 'node/' . $node->nid . '/team');
      $node->content['project_team_button'] = _feature_commons_extra_field_view('project_team_button', '', $node, $view_mode, $langcode, $field_content);
    }
  }
}