class StateDemo

Same name in other branches
  1. 4.0.x modules/form_api_example/src/Form/StateDemo.php \Drupal\form_api_example\Form\StateDemo

Implements the state demo form controller.

This example demonstrates using the #states property to bind the visibility of a form element to the value of another element in the form. In the example, when the user checks the "Need Special Accommodation" checkbox, additional form elements are made visible.

The submit handler for this form is implemented by the \Drupal\form_api_example\Form\DemoBase class.

Hierarchy

Expanded class hierarchy of StateDemo

See also

\Drupal\Core\Form\FormBase

\Drupal\form_api_example\Form\DemoBase

drupal_process_states()

1 string reference to 'StateDemo'
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/StateDemo.php, line 22

Namespace

Drupal\form_api_example\Form
View source
class StateDemo extends DemoBase {
    
    /**
     * Build the simple form.
     *
     * @inheritdoc
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $form['description'] = [
            '#type' => 'item',
            '#markup' => $this->t('This example demonstrates the #states property. #states makes an element visibility dependent on another.'),
        ];
        $form['needs_accommodation'] = [
            '#type' => 'checkbox',
            '#title' => 'Need Special Accommodations?',
        ];
        // The #states property used here binds the visibility of the
        // container element to the value of the needs_accommodation checkbox above.
        $form['accommodation'] = [
            '#type' => 'container',
            '#attributes' => [
                'class' => 'accommodation',
            ],
            // #states is an associative array. Each key is the name of a state to
            // apply to the element, such as 'visible'. Each value is another array,
            // making a list of conditions that denote when the state should be
            // applied. Every condition is a key/value pair, whose key is a jQuery
            // selector that denotes another element on the page, and whose value is
            // an array of conditions, which must be met on in order for the state to
            // be applied.
            //
            // For additional documentation on the #states property including a list
            // of valid states and conditions see drupal_process_states().
'#states' => [
                // The state being affected is "invisible".
'invisible' => [
                    // Drupal will only apply this state when the element that satisfies
                    // the selector input[name="needs_accommodation"] is un-checked.
':input[name="needs_accommodation"]' => [
                        'checked' => FALSE,
                    ],
                ],
            ],
        ];
        $form['accommodation']['diet'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Dietary Restrictions'),
        ];
        // Add a submit button that handles the submission of the form.
        $form['actions']['submit'] = [
            '#type' => 'submit',
            '#value' => $this->t('Submit'),
        ];
        return $form;
    }
    
    /**
     * Getter method for Form ID.
     *
     * @inheritdoc
     */
    public function getFormId() {
        return 'form_api_example_state_demo';
    }
    
    /**
     * Implements submitForm callback.
     *
     * @inheritdoc
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        // Find out what was submitted.
        $values = $form_state->getValues();
        if ($values['needs_accommodation']) {
            $this->messenger()
                ->addMessage($this->t('Dietary Restriction Requested: %diet', [
                '%diet' => $values['diet'],
            ]));
        }
    }

}

Members

Title Sort descending Modifiers Object type Summary Overriden Title Overrides
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 '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.
StateDemo::buildForm public function Build the simple form. Overrides FormInterface::buildForm
StateDemo::getFormId public function Getter method for Form ID. Overrides FormInterface::getFormId
StateDemo::submitForm public function Implements submitForm callback. Overrides DemoBase::submitForm
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.