Example: Programmatically adding field collection entries to a node

In this example a function adds an entry to a node with a field collection named field_activity_log.

function foo_log_activity($node, $message, $uid = NULL) {
  // Load the controller class file.
  module_load_include('inc', 'entity', 'includes/entity.controller');

  // Use the currently logged in user if a $uid argument is not defined.
  global $user;
  if (empty($uid)) {
    $uid = $user->uid;
  }

  // Grab the current time in the format required by our date field. We need
  // gmdate() here to get a time in UTC which is how everything is stored
  // internally.
  $now = gmdate('Y-m-d H:i:s');

  // Setup the values in the structure expected by the field_collection entity.
  $values = array(
    'field_name' => 'field_activity_log',
    'field_activity_log_date' => array(
      LANGUAGE_NONE => array(array('value' => $now)),
    ),
    'field_activity_log_message' => array(
      LANGUAGE_NONE => array(array('value' => $message)),
    ),
    'field_activity_log_user' => array(
      LANGUAGE_NONE => array(array('uid' => $uid)),
    ),
  );
  $entity = entity_create('field_collection_item', $values);

  // Attach the field_collection entity to the application node. This has to
  // happen separately so that it actually works -- you can't just specify
  // this via the $values array.
  $entity->setHostEntity('node', $node);

  // Save the entity. Since it's attached to the right application node, this
  // will both create the field_collection entity and update the application
  // node to point to the new field_activity_log record.
  $entity->save();
}