FormTestVerticalTabsWithSummaryForm.php

<?php

declare (strict_types=1);
namespace Drupal\form_test\Form;

use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Builds a simple form to test vertical-tabs form element with tab summaries.
 *
 * @internal
 */
class FormTestVerticalTabsWithSummaryForm extends FormBase {
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return '_form_test_vertical_tabs_with_summary_form';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $form['information'] = [
            '#type' => 'vertical_tabs',
            '#default_tab' => 'edit-tab1',
        ];
        $form['tab1'] = [
            '#type' => 'details',
            '#title' => $this->t('Tab 1'),
            '#group' => 'information',
        ];
        $form['tab1']['field1'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Field 1'),
        ];
        $form['tab2'] = [
            '#type' => 'details',
            '#title' => $this->t('Tab 2'),
            '#group' => 'information',
        ];
        $form['tab2']['field2'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Field 2'),
        ];
        $form['actions']['#type'] = 'actions';
        $form['actions']['submit'] = [
            '#type' => 'submit',
            '#value' => $this->t('Save'),
            '#button_type' => 'primary',
        ];
        // Attach the library that sets the vertical tab summaries.
        $form['#attached']['library'][] = 'form_test/form_test';
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) : void {
        $this->messenger()
            ->addStatus($this->t('Form submitted.'));
    }

}