function hook_field_attach_form

Act on field_attach_form().

This hook is invoked after the field module has performed the operation. Implementing modules should alter the $form or $form_state parameters.

Parameters

\Drupal\Core\Entity\EntityInterface $entity: The entity for which an edit form is being built.

$form: The form structure field elements are attached to. This might be a full form structure, or a sub-element of a larger form. The $form['#parents'] property can be used to identify the corresponding part of $form_state['values']. Hook implementations that need to act on the top-level properties of the global form (like #submit, #validate...) can add a #process callback to the array received in the $form parameter, and act on the $complete_form parameter in the process callback.

$form_state: An associative array containing the current state of the form.

$langcode: The language the field values are going to be entered in. If no language is provided the default site language will be used.

Related topics

Field Attach API
Operates on Field API data attached to Drupal entities.
Hooks
Allow modules to interact with the Drupal core.
1 invocation of hook_field_attach_form()
field_attach_form in drupal/core/modules/field/field.attach.inc
Adds form elements for all fields for an entity to a form structure.

File

drupal/core/modules/field/field.api.php, line 861

Code

function hook_field_attach_form(\Drupal\Core\Entity\EntityInterface $entity, &$form, &$form_state, $langcode) {

  // Add a checkbox allowing a given field to be emptied.
  // See hook_field_attach_extract_form_values() for the corresponding
  // processing code.
  $form['empty_field_foo'] = array(
    '#type' => 'checkbox',
    '#title' => t("Empty the 'field_foo' field"),
  );
}