FormTestLanguageSelectForm.php

<?php

namespace Drupal\form_test\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Language\LanguageInterface;
use Symfony\Component\HttpFoundation\JsonResponse;

/**
 * Builds a form to test the language select form element.
 *
 * @internal
 */
class FormTestLanguageSelectForm extends FormBase {
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'form_test_language_select';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $form['languages_all'] = [
            '#title' => t('Languages: All'),
            '#type' => 'language_select',
            '#languages' => LanguageInterface::STATE_ALL,
            '#default_value' => 'xx',
        ];
        $form['languages_configurable'] = [
            '#title' => t('Languages: Configurable'),
            '#type' => 'language_select',
            '#languages' => LanguageInterface::STATE_CONFIGURABLE,
            '#default_value' => 'en',
        ];
        $form['languages_locked'] = [
            '#title' => t('Languages: Locked'),
            '#type' => 'language_select',
            '#languages' => LanguageInterface::STATE_LOCKED,
        ];
        $form['languages_config_and_locked'] = [
            '#title' => t('Languages: Configurable and locked'),
            '#type' => 'language_select',
            '#languages' => LanguageInterface::STATE_CONFIGURABLE | LanguageInterface::STATE_LOCKED,
            '#default_value' => 'dummy_value',
        ];
        $form['language_custom_options'] = [
            '#title' => t('Languages: Custom'),
            '#type' => 'language_select',
            '#languages' => LanguageInterface::STATE_CONFIGURABLE | LanguageInterface::STATE_LOCKED,
            '#options' => [
                'opt1' => 'First option',
                'opt2' => 'Second option',
                'opt3' => 'Third option',
            ],
            '#default_value' => 'opt2',
        ];
        $form['submit'] = [
            '#type' => 'submit',
            '#value' => 'Submit',
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $form_state->setResponse(new JsonResponse($form_state->getValues()));
    }

}