Initial Drupal 8 Port by JeroenT, khaled.zaidan

name = Multiple Selects

description = Adding a possibility to use multiple select fields rather than a multiselect field.

package = Fields

dependency[] = options

core = 7.x

name: Multiple Selects

description: Adding a possibility to use multiple select fields rather than a multiselect field.

package: Fields

type: module

version: 1.0

core: 8.x

dependencies:

  - field_ui

  - options

<?php

/**

 * Implements hook_theme().

 */

function multiple_selects_theme() {

  return array(

    'multiple_selects_none' => array(

      'variables' => array('instance' => NULL, 'option' => NULL),

    ),

  );

}

/**

 * Returns HTML for the label for the empty value for options that are not required.

 *

 * The default theme will display N/A for a radio list and '- None -' for a select.

 *

 * @param $variables

 *   An associative array containing:

 *   - instance: An array representing the widget requesting the options.

 *

 * @ingroup themeable

 */

function theme_multiple_selects_none($variables) {

  $instance = $variables['instance'];

  $option = $variables['option'];

  $output = ($option == 'option_none' ? t('- None -') : t('- Select a value -'));

  return $output;

}

/**

 * Implements hook_field_widget_info().

 *

 * Field type modules willing to use those widgets should:

 * - Use hook_field_widget_info_alter() to append their field own types to the

 *   list of types supported by the widgets,

 */

function multiple_selects_field_widget_info() {

  return array(

    'multiple_selects' => array(

      'label' => t('Multiple Selects list'),

      'field types' => array(

        'entityreference',

        'node_reference',

        'user_reference',

        'taxonomy_term_reference',

        'list_integer',

        'list_float',

        'list_text',

        'list_boolean',

        'commerce_product_reference',

      ),

    ),

  );

}

/**

 * Implements hook_field_widget_form().

 */

function multiple_selects_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {

  // Abstract over the actual field columns, to allow different field types to

  // reuse those widgets.

  $value_key = key($field['columns']);

  $type = "select";

  $multiple = 1;

  $required = $element['#required'];

  $has_value = isset($items[0][$value_key]);

  $properties = _options_properties($type, $multiple, $required, $has_value);

  $entity_type = $element['#entity_type'];

  $entity = $element['#entity'];

  // Prepare the list of options.

  $options = _multiple_selects_get_options($field, $instance, $properties, $entity_type, $entity);

  // Enforcing the element to have the value of the field instance label.

  $element['#title'] = $instance['label'];

  $element['#title_display'] = 'none';

  $widget = $element;

  $widget += array(

    '#type' => 'select',

    '#default_value' => isset($items[$delta][$value_key]) ? $items[$delta][$value_key] : NULL,

    '#options' => $options,

    '#element_validate' => array('multiple_selects_widget_validate'),

    '#value_key' => $value_key,

    '#properties' => $properties,

  );

  $element[$value_key] = $widget;

  return $element;

}

/**

 * Form element validation handler for options element.

 */

function multiple_selects_widget_validate($element, &$form_state) {

  $value_key = $element['#value_key'];

  $properties = $element['#properties'];

  $value = $element['#value'];

  if ($element['#required'] && $element['#value'] === '_none') {

    form_error($element, t('!name field is required.', array('!name' => $element['#title'])));

  }

  if ($properties['empty_option']) {

    if ($value === '_none') {

      form_set_value($element, NULL, $form_state);

    }    

  }

}

/**

 * Implements hook_field_widget_error().

 */

function multiple_selects_field_widget_error($element, $error, $form, &$form_state) {

  form_error($element, $error['message']);

}

/**

 * Collects the options for a field.

 */

function _multiple_selects_get_options($field, $instance, $properties, $entity_type, $entity) {

  // Get the list of options.

  $options = (array) module_invoke($field['module'], 'options_list', $field, $instance, $entity_type, $entity);

  // Sanitize the options.

  _options_prepare_options($options, $properties);

  if (!$properties['optgroups']) {

    $options = options_array_flatten($options);

  }

  if ($properties['empty_option']) {

    $label = theme('multiple_selects_none', array('instance' => $instance, 'option' => $properties['empty_option']));

    $options = array('_none' => $label) + $options;

  }

  return $options;

}

<?php

namespace Drupal\multiple_selects\Plugin\Field\FieldWidget;

use Drupal\Core\Field\FieldItemListInterface;

use Drupal\Core\Form\FormStateInterface;

use Drupal\Core\Field\Plugin\Field\FieldWidget\OptionsSelectWidget;

use Drupal\Core\Field\WidgetInterface;

/**

 * Plugin implementation of the 'options_select' widget.

 *

 * @FieldWidget(

 *   id = "multiple_options_select",

 *   label = @Translation("Multiple select list(s)"),

 *   field_types = {

 *     "entity_reference",

 *     "list_integer",

 *     "list_float",

 *     "list_string"

 *   },

 * )

 */

class OptionsMultipleSelectWidget extends OptionsSelectWidget implements WidgetInterface {

  /**

   * {@inheritdoc}

   */

  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {

    $element = parent::formElement($items, $delta, $element, $form, $form_state);

    $element[$this->column] = $element;

    $element[$this->column]['#default_value'] = empty($items[$delta]->{$this->column}) ? '_none' : $items[$delta]->{$this->column};

    $element[$this->column]['#multiple'] = FALSE;

    unset($element['#type']);

    return $element;

  }

  /**

   * {@inheritdoc}

   */

  public static function validateElement(array $element, FormStateInterface $form_state) {

    if ($element['#required'] && $element['#value'] === '_none') {

      $form_state->setError($element, t('@name field is required.', array('@name' => $element['#title'])));

    }

    if (isset($element['#value']) && $element['#value'] === '_none') {

      $form_state->setValueForElement($element, NULL);

    }

  }

}