class AjaxAddMore

Same name in other branches
  1. 4.0.x modules/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

Title Sort descending Modifiers Object type Summary Overriden Title Overrides
AjaxAddMore::addmoreCallback public function Callback for both ajax-enabled buttons.
AjaxAddMore::addOne public function Submit handler for the &quot;add-one-more&quot; button.
AjaxAddMore::buildForm public function Form with &#039;add more&#039; and &#039;remove&#039; 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 &quot;remove one&quot; button.
AjaxAddMore::submitForm public function Final submit handler. Overrides DemoBase::submitForm
DependencySerializationTrait::$_entityStorages protected property
DependencySerializationTrait::$_serviceIds protected property
DependencySerializationTrait::__sleep public function 1
DependencySerializationTrait::__wakeup public function 2
FormBase::$configFactory protected property The config factory. 3
FormBase::$requestStack protected property The request stack. 1
FormBase::$routeMatch protected property The route match.
FormBase::config protected function Retrieves a configuration object.
FormBase::configFactory protected function Gets the config factory for this form. 3
FormBase::container private function Returns the service container.
FormBase::create public static function Instantiates a new instance of this class. Overrides ContainerInjectionInterface::create 105
FormBase::currentUser protected function Gets the current user.
FormBase::getRequest protected function Gets the request object.
FormBase::getRouteMatch protected function Gets the route match.
FormBase::logger protected function Gets the logger for a specific channel.
FormBase::redirect protected function Returns a redirect response object for the specified route.
FormBase::resetConfigFactory public function Resets the configuration factory.
FormBase::setConfigFactory public function Sets the config factory for this form.
FormBase::setRequestStack public function Sets the request stack object to use.
FormBase::validateForm public function Form validation handler. Overrides FormInterface::validateForm 73
LoggerChannelTrait::$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::$messenger protected property The messenger. 17
MessengerTrait::messenger public function Gets the messenger. 17
MessengerTrait::setMessenger public function Sets the messenger.
RedirectDestinationTrait::$redirectDestination protected property The redirect destination service. 1
RedirectDestinationTrait::getDestinationArray protected function Prepares a &#039;destination&#039; 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. 3
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.