respondjs-8.x-1.x-dev/src/Form/RespondjsSettingForm.php

<?php

namespace Drupal\respondjs\Form;

use Drupal\Core\Form\ConfigFormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Form handler for configuring respondjs.
 */
class RespondjsSettingForm extends ConfigFormBase {

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'respondjs_form';
  }

  /**
   * {@inheritdoc}
   */
  protected function getEditableConfigNames() {
    return [
      'respondjs.settings',
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $config = $this->configFactory->getEditable('respondjs.settings');

    $form['warn'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Do not warn me about CSS aggregation.'),
      '#description' => $this->t("Check this box if you'd rather not see the warning about CSS aggregation.<br> Disabling the warning will not make the respond.js function properly, but it will suppress the error message."),
      '#default_value' => !empty($config->get('warn')) ? $config->get('warn') : FALSE,
    ];

    return parent::buildForm($form, $form_state);
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $this->configFactory->getEditable('respondjs.settings')
      ->set('warn', (bool) $form_state->getValue('warn'))
      ->save();

    parent::submitForm($form, $form_state);
  }

}