Drupal 7 Module Development

Chapter 7
We can, of course, have much more complex formatters. To use our map example we
have seen previously, a formatter could take a series of coordinate data and output
them on a map using a mapping service. As long as we return a renderable array
to Drupal, we can do whatever we want.
Managing non-Field fields
One of the advantages of using the Field system is that it gives us a consistent,
powerful UI for all Field data that we add to an entity. However, an entity may have
non-Field data on it as well. A node or artwork title, for instance, is not a Field. The
poll module in core doesn't use Fields for the poll configuration. An entity that is
being pulled from a third party system may have all sorts of data associated with it
that does not live in a Field module.
Fortunately, Drupal offers a way for us to integrate that data into the Field UI. Let's
go back to the artwork module from Chapter 6, Working with Content and integrate
the title into the Field system. It takes but a single hook:
function artwork_field_extra_fields() {
$extra = array();
foreach (artwork_types() as $type) {
$extra['artwork'][$type->type] = array(
'form' => array(
'title' => array(
'label' => t('Title'),
'description' => t('The name of the artwork'),
'weight' => -5,
),
),
'display' => array(
'title' => array(
'label' => t('Title'),
'description' => t('The name of the artwork'),
'weight' => -5,
),
),
);
}
return $extra;
}
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