function Radios::valueCallback

Overrides FormElement::valueCallback

File

core/lib/Drupal/Core/Render/Element/Radios.php, line 99

Class

Radios

Provides a form element for a set of radio buttons.

Namespace

Code

public static function valueCallback(&$element, $input, FormStateInterface $form_state) {
    if ($input !== FALSE) {
        // When there's user input (including NULL), return it as the value.
        // However, if NULL is submitted, FormBuilder::handleInputElement() will
        // apply the default value, and we want that validated against #options
        // unless it's empty. (An empty #default_value, such as NULL or FALSE, can
        // be used to indicate that no radio button is selected by default.)
        if (!isset($input) && !empty($element['#default_value'])) {
            $element['#needs_validation'] = TRUE;
        }
        return $input;
    }
    else {
        // For default value handling, simply return #default_value. Additionally,
        // for a NULL default value, set #has_garbage_value to prevent
        // FormBuilder::handleInputElement() converting the NULL to an empty
        // string, so that code can distinguish between nothing selected and the
        // selection of a radio button whose value is an empty string.
        $value = $element['#default_value'] ?? NULL;
        if (!isset($value)) {
            $element['#has_garbage_value'] = TRUE;
        }
        return $value;
    }
}