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class AjaxAddMore in Examples for Developers 3.x

Same name and namespace in other branches
  1. 8 form_api_example/src/Form/AjaxAddMore.php \Drupal\form_api_example\Form\AjaxAddMore

Implements the ajax demo form controller.

This example demonstrates using ajax callbacks to add people's names to a list of picnic attendees.

Hierarchy

Expanded class hierarchy of AjaxAddMore

See also

\Drupal\Core\Form\FormBase

\Drupal\Core\Form\ConfigFormBase

1 string reference to 'AjaxAddMore'
form_api_example.routing.yml in modules/form_api_example/form_api_example.routing.yml
modules/form_api_example/form_api_example.routing.yml

File

modules/form_api_example/src/Form/AjaxAddMore.php, line 16

Namespace

Drupal\form_api_example\Form
View source 
class AjaxAddMore extends DemoBase {

  /**
   * Form with 'add more' and 'remove' buttons.
   *
   * This example shows a button to "add more" - add another textfield, and
   * the corresponding "remove" button.
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $form['description'] = [
      '#type' => 'item',
      '#markup' => $this
        ->t('This example shows an add-more and a remove-last button.'),
    ];

    // Gather the number of names in the form already.
    $num_names = $form_state
      ->get('num_names');

    // We have to ensure that there is at least one name field.
    if ($num_names === NULL) {
      $name_field = $form_state
        ->set('num_names', 1);
      $num_names = 1;
    }
    $form['#tree'] = TRUE;
    $form['names_fieldset'] = [
      '#type' => 'fieldset',
      '#title' => $this
        ->t('People coming to picnic'),
      '#prefix' => '<div id="names-fieldset-wrapper">',
      '#suffix' => '</div>',
    ];
    for ($i = 0; $i < $num_names; $i++) {
      $form['names_fieldset']['name'][$i] = [
        '#type' => 'textfield',
        '#title' => $this
          ->t('Name'),
      ];
    }
    $form['names_fieldset']['actions'] = [
      '#type' => 'actions',
    ];
    $form['names_fieldset']['actions']['add_name'] = [
      '#type' => 'submit',
      '#value' => $this
        ->t('Add one more'),
      '#submit' => [
        '::addOne',
      ],
      '#ajax' => [
        'callback' => '::addmoreCallback',
        'wrapper' => 'names-fieldset-wrapper',
      ],
    ];

    // If there is more than one name, add the remove button.
    if ($num_names > 1) {
      $form['names_fieldset']['actions']['remove_name'] = [
        '#type' => 'submit',
        '#value' => $this
          ->t('Remove one'),
        '#submit' => [
          '::removeCallback',
        ],
        '#ajax' => [
          'callback' => '::addmoreCallback',
          'wrapper' => 'names-fieldset-wrapper',
        ],
      ];
    }
    $form['actions']['submit'] = [
      '#type' => 'submit',
      '#value' => $this
        ->t('Submit'),
    ];
    return $form;
  }

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

  /**
   * Callback for both ajax-enabled buttons.
   *
   * Selects and returns the fieldset with the names in it.
   */
  public function addmoreCallback(array &$form, FormStateInterface $form_state) {
    return $form['names_fieldset'];
  }

  /**
   * Submit handler for the "add-one-more" button.
   *
   * Increments the max counter and causes a rebuild.
   */
  public function addOne(array &$form, FormStateInterface $form_state) {
    $name_field = $form_state
      ->get('num_names');
    $add_button = $name_field + 1;
    $form_state
      ->set('num_names', $add_button);

    // Since our buildForm() method relies on the value of 'num_names' to
    // generate 'name' form elements, we have to tell the form to rebuild. If we
    // don't do this, the form builder will not call buildForm().
    $form_state
      ->setRebuild();
  }

  /**
   * Submit handler for the "remove one" button.
   *
   * Decrements the max counter and causes a form rebuild.
   */
  public function removeCallback(array &$form, FormStateInterface $form_state) {
    $name_field = $form_state
      ->get('num_names');
    if ($name_field > 1) {
      $remove_button = $name_field - 1;
      $form_state
        ->set('num_names', $remove_button);
    }

    // Since our buildForm() method relies on the value of 'num_names' to
    // generate 'name' form elements, we have to tell the form to rebuild. If we
    // don't do this, the form builder will not call buildForm().
    $form_state
      ->setRebuild();
  }

  /**
   * Final submit handler.
   *
   * Reports what values were finally set.
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $values = $form_state
      ->getValue([
      'names_fieldset',
      'name',
    ]);
    $output = $this
      ->t('These people are coming to the picnic: @names', [
      '@names' => implode(', ', $values),
    ]);
    $this
      ->messenger()
      ->addMessage($output);
  }

}

Members

Namesort descending Modifiers Type Description Overrides
AjaxAddMore::addmoreCallback public function Callback for both ajax-enabled buttons.
AjaxAddMore::addOne public function Submit handler for the "add-one-more" button.
AjaxAddMore::buildForm public function Form with 'add more' and 'remove' buttons. Overrides FormInterface::buildForm
AjaxAddMore::getFormId public function Returns a unique string identifying the form. Overrides FormInterface::getFormId
AjaxAddMore::removeCallback public function Submit handler for the "remove one" button.
AjaxAddMore::submitForm public function Final submit handler. Overrides DemoBase::submitForm
DependencySerializationTrait::$_entityStorages protected property
DependencySerializationTrait::$_serviceIds protected property
DependencySerializationTrait::__sleep public function 2
DependencySerializationTrait::__wakeup public function 2
FormBase::$configFactory protected property The config factory. 3
FormBase::$requestStack protected property The request stack. 1
FormBase::$routeMatch protected property The route match.
FormBase::config protected function Retrieves a configuration object.
FormBase::configFactory protected function Gets the config factory for this form. 3
FormBase::container private function Returns the service container.
FormBase::create public static function Instantiates a new instance of this class. Overrides ContainerInjectionInterface::create 105
FormBase::currentUser protected function Gets the current user.
FormBase::getRequest protected function Gets the request object.
FormBase::getRouteMatch protected function Gets the route match.
FormBase::logger protected function Gets the logger for a specific channel.
FormBase::redirect protected function Returns a redirect response object for the specified route.
FormBase::resetConfigFactory public function Resets the configuration factory.
FormBase::setConfigFactory public function Sets the config factory for this form.
FormBase::setRequestStack public function Sets the request stack object to use.
FormBase::validateForm public function Form validation handler. Overrides FormInterface::validateForm 72
LoggerChannelTrait::$loggerFactory protected property The logger channel factory service.
LoggerChannelTrait::getLogger protected function Gets the logger for a specific channel.
LoggerChannelTrait::setLoggerFactory public function Injects the logger channel factory.
MessengerTrait::$messenger protected property The messenger. 27
MessengerTrait::messenger public function Gets the messenger. 27
MessengerTrait::setMessenger public function Sets the messenger.
RedirectDestinationTrait::$redirectDestination protected property The redirect destination service. 1
RedirectDestinationTrait::getDestinationArray protected function Prepares a 'destination' URL query parameter for use with \Drupal\Core\Url.
RedirectDestinationTrait::getRedirectDestination protected function Returns the redirect destination service.
RedirectDestinationTrait::setRedirectDestination public function Sets the redirect destination service.
StringTranslationTrait::$stringTranslation protected property The string translation service. 4
StringTranslationTrait::formatPlural protected function Formats a string containing a count of items.
StringTranslationTrait::getNumberOfPlurals protected function Returns the number of plurals supported by a given language.
StringTranslationTrait::getStringTranslation protected function Gets the string translation service.
StringTranslationTrait::setStringTranslation public function Sets the string translation service to use. 2
StringTranslationTrait::t protected function Translates a string to the current language or to a given language.