/**
* {@inheritdoc}
*/
protected function formMultipleElements(FieldItemListInterface $items, array &$form, FormStateInterface $form_state) {
$field_name = $this->fieldDefinition->getName();
$cardinality = $this->fieldDefinition->getFieldStorageDefinition()->getCardinality();
$parents = $form['#parents'];
// Assign a unique identifier to each widget.
$id_prefix = implode('-', array_merge($parents, [$field_name]));
$wrapper_id = Html::getUniqueId($id_prefix . '-add-more-wrapper');
$this->setWrapperId($wrapper_id);
// Load the items for form rebuilds from the field state as they might not
// be in $form_state->getValues() because of validation limitations. Also,
// they are only passed in as $items when editing existing entities.
$field_state = static::getWidgetState($parents, $field_name, $form_state);
if (isset($field_state['items'])) {
$items->setValue($field_state['items']);
}
// Lower the 'items_count' field state property in order to prevent the
// parent implementation to append an extra empty item.
if ($cardinality == FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED) {
$field_state['items_count'] = (count($items) > 1) ? count($items) - 1 : 0;
static::setWidgetState($parents, $field_name, $form_state, $field_state);
}
$elements = parent::formMultipleElements($items, $form, $form_state);
if ($elements) {
if (isset($elements['add_more'])) {
// Update the HTML wrapper ID with the one generated by us.
$elements['#prefix'] = '<div id="' . $this->getWrapperId() . '">';
$add_more_button = $elements['add_more'];
$add_more_button['#value'] = $this->t('Add item');
$add_more_button['#ajax']['callback'] = [get_class($this), 'getWidgetElementAjax'];
$add_more_button['#ajax']['wrapper'] = $this->getWrapperId();
$elements['add_more'] = [
'#type' => 'container',
'#tree' => TRUE,
'#attributes' => ['class' => ['form--inline']],
'new_item' => parent::formElement($items, -1, [], $form, $form_state),
'submit' => $add_more_button,
];
}
}
return $elements;
}
