NodeFormHooks.php

<?php

declare (strict_types=1);
namespace Drupal\node\Hook;

use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Hook\Attribute\Hook;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\Core\Url;

/**
 * Form hook implementations for the node module.
 */
class NodeFormHooks {
  use StringTranslationTrait;
  public function __construct(protected readonly ConfigFactoryInterface $configFactory) {
  }
  
  /**
   * Implements hook_form_FORM_ID_alter().
   *
   * Alters the theme form to use the admin theme on node editing.
   *
   * @see self::systemThemesAdminFormSubmit()
   */
  public function formSystemThemesAdminFormAlter(&$form, FormStateInterface $form_state, $form_id) : void {
    $form['admin_theme']['use_admin_theme'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Use the administration theme when editing or creating content'),
      '#description' => $this->t('Control which roles can "View the administration theme" on the <a href=":permissions">Permissions page</a>.', [
        ':permissions' => Url::fromRoute('user.admin_permissions.module', [
          'modules' => 'system',
        ])->toString(),
      ]),
      '#default_value' => $this->configFactory
        ->getEditable('node.settings')
        ->get('use_admin_theme'),
    ];
    $form['#submit'][] = [
      self::class,
      'systemThemesAdminFormSubmit',
    ];
  }
  
  /**
   * Form submission handler for system_themes_admin_form().
   *
   * @see self::formSystemThemesAdminFormAlter
   */
  public static function systemThemesAdminFormSubmit($form, FormStateInterface $form_state) : void {
    \Drupal::configFactory()->getEditable('node.settings')
      ->set('use_admin_theme', $form_state->getValue('use_admin_theme'))
      ->save();
  }

}