public function DynamicFormSections::buildForm in Examples for Developers 3.x

Same name and namespace in other branches

1. 8 ajax_example/src/Form/DynamicFormSections.php \Drupal\ajax_example\Form\DynamicFormSections::buildForm()

Form constructor.

Parameters

array $form: An associative array containing the structure of the form.

\Drupal\Core\Form\FormStateInterface $form_state: The current state of the form.

Return value

array The form structure.

Overrides FormInterface::buildForm

File

modules/ajax_example/src/Form/DynamicFormSections.php, line 34

Class

DynamicFormSections

Dynamically-enabled form with graceful no-JS degradation.

Namespace

Drupal\ajax_example\Form

Code

public function buildForm(array $form, FormStateInterface $form_state, $nojs = NULL) {

  // Add our CSS and tiny JS to hide things when they should be hidden.
  $form['#attached']['library'][] = 'ajax_example/ajax_example.library';

  // Explanatory text with helpful links.
  $form['info'] = [
    '#markup' => $this
      ->t('<p>Like other examples in this module, this form has a path that
        can be modified with /nojs to simulate its behavior without JavaScript.
        </p><ul>
        <li>@try_it_without_ajax</li>
        <li>@try_it_with_ajax</li>
      </ul>', [
      '@try_it_without_ajax' => Link::createFromRoute($this
        ->t('Try it without AJAX'), 'ajax_example.dynamic_form_sections', [
        'nojs' => 'nojs',
      ])
        ->toString(),
      '@try_it_with_ajax' => Link::createFromRoute($this
        ->t('Try it with AJAX'), 'ajax_example.dynamic_form_sections')
        ->toString(),
    ]),
  ];
  $form['question_type_select'] = [
    // This is our select dropdown.
    '#type' => 'select',
    '#title' => $this
      ->t('Question style'),
    // We have a variety of form items you can use to get input from the user.
    '#options' => [
      'Choose question style' => 'Choose question style',
      'Multiple Choice' => 'Multiple Choice',
      'True/False' => 'True/False',
      'Fill-in-the-blanks' => 'Fill-in-the-blanks',
    ],
    // The #ajax section tells the AJAX system that whenever this dropdown
    // emits an event, it should call the callback and put the resulting
    // content into the wrapper we specify. The questions-fieldset-wrapper is
    // defined below.
    '#ajax' => [
      'wrapper' => 'questions-fieldset-wrapper',
      'callback' => '::promptCallback',
    ],
  ];

  // The CSS for this module hides this next button if JS is enabled.
  $form['question_type_submit'] = [
    '#type' => 'submit',
    '#value' => $this
      ->t('Choose'),
    '#attributes' => [
      'class' => [
        'ajax-example-inline',
      ],
    ],
    // No need to validate when submitting this.
    '#limit_validation_errors' => [],
    '#validate' => [],
  ];

  // This section allows us to demonstrate no-AJAX use without turning off
  // javascript in the browser.
  if ($nojs != 'nojs') {

    // Allow JavaScript to hide the choose button if we're using AJAX.
    $form['question_type_submit']['#attributes']['class'][] = 'ajax-example-hide';
  }
  else {

    // Remove #ajax from the above, so it won't perform AJAX behaviors.
    unset($form['question_type_select']['#ajax']);
  }

  // This fieldset just serves as a container for the part of the form
  // that gets rebuilt. It has a nice line around it so you can see it.
  $form['questions_fieldset'] = [
    '#type' => 'details',
    '#title' => $this
      ->t('Stuff will appear here'),
    '#open' => TRUE,
    // We set the ID of this fieldset to questions-fieldset-wrapper so the
    // AJAX command can replace it.
    '#attributes' => [
      'id' => 'questions-fieldset-wrapper',
    ],
  ];

  // When the AJAX request comes in, or when the user hit 'Submit' if there is
  // no JavaScript, the form state will tell us what the user has selected
  // from the dropdown. We can look at the value of the dropdown to determine
  // which secondary form to display.
  $question_type = $form_state
    ->getValue('question_type_select');
  if (!empty($question_type) && $question_type !== 'Choose question style') {
    $form['questions_fieldset']['question'] = [
      '#markup' => $this
        ->t('Who was the first president of the U.S.?'),
    ];

    // Build up a secondary form, based on the type of question the user
    // chose.
    switch ($question_type) {
      case 'Multiple Choice':
        $form['questions_fieldset']['question'] = [
          '#type' => 'radios',
          '#title' => $this
            ->t('Who was the first president of the United States'),
          '#options' => [
            'George Bush' => 'George Bush',
            'Adam McGuire' => 'Adam McGuire',
            'Abraham Lincoln' => 'Abraham Lincoln',
            'George Washington' => 'George Washington',
          ],
        ];
        break;
      case 'True/False':
        $form['questions_fieldset']['question'] = [
          '#type' => 'radios',
          '#title' => $this
            ->t('Was George Washington the first president of the United States?'),
          '#options' => [
            'George Washington' => 'True',
            0 => 'False',
          ],
          '#description' => $this
            ->t('Click "True" if you think George Washington was the first president of the United States.'),
        ];
        break;
      case 'Fill-in-the-blanks':
        $form['questions_fieldset']['question'] = [
          '#type' => 'textfield',
          '#title' => $this
            ->t('Who was the first president of the United States'),
          '#description' => $this
            ->t('Please type the correct answer to the question.'),
        ];
        break;
    }
    $form['questions_fieldset']['submit'] = [
      '#type' => 'submit',
      '#value' => $this
        ->t('Submit your answer'),
    ];
  }
  return $form;
}