class Radio in Drupal 8

Provides a form element for a single radio button.

This is an internal element that is primarily used to render the radios form element. Refer to \Drupal\Core\Render\Element\Radios for more documentation.

Plugin annotation

@FormElement("radio");

Hierarchy

• class \Drupal\Component\Plugin\PluginBase implements DerivativeInspectionInterface, PluginInspectionInterface
  • class \Drupal\Core\Plugin\PluginBase uses DependencySerializationTrait, MessengerTrait, StringTranslationTrait
    • class \Drupal\Core\Render\Element\RenderElement implements ElementInterface
      • class \Drupal\Core\Render\Element\FormElement implements FormElementInterface
        • class \Drupal\Core\Render\Element\Radio

See also

\Drupal\Core\Render\Element\Radios

\Drupal\Core\Render\Element\Checkbox

7 #type uses of Radio

ArgumentPluginBase::processContainerRadios in core/modules/views/src/Plugin/views/argument/ArgumentPluginBase.php

Custom form radios process function.

FormElementsRenderTest::testDrupalRenderFormElements in core/modules/system/tests/src/Kernel/Common/FormElementsRenderTest.php

Tests rendering form elements without passing through \Drupal::formBuilder()->doBuildForm().

LanguageListBuilder::buildRow in core/modules/language/src/LanguageListBuilder.php

Builds a row for an entity in the entity listing.

Radios::processRadios in core/lib/Drupal/Core/Render/Element/Radios.php

Expands a radios element into individual radio elements.

Table::buildOptionsForm in core/modules/views/src/Plugin/views/style/Table.php

Render the given style.

... See full list

File

core/lib/Drupal/Core/Render/Element/Radio.php, line 18

Namespace

Drupal\Core\Render\Element

class Radio extends FormElement {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = get_class($this);
    return [
      '#input' => TRUE,
      '#default_value' => NULL,
      '#process' => [
        [
          $class,
          'processAjaxForm',
        ],
      ],
      '#pre_render' => [
        [
          $class,
          'preRenderRadio',
        ],
      ],
      '#theme' => 'input__radio',
      '#theme_wrappers' => [
        'form_element',
      ],
      '#title_display' => 'after',
    ];
  }

  /**
   * Prepares a #type 'radio' render element for input.html.twig.
   *
   * @param array $element
   *   An associative array containing the properties of the element.
   *   Properties used: #required, #return_value, #value, #attributes, #title,
   *   #description. The #name property will be sanitized before output. This is
   *   currently done by initializing Drupal\Core\Template\Attribute with all
   *   the attributes.
   *
   * @return array
   *   The $element with prepared variables ready for input.html.twig.
   */
  public static function preRenderRadio($element) {
    $element['#attributes']['type'] = 'radio';
    Element::setAttributes($element, [
      'id',
      'name',
      '#return_value' => 'value',
    ]);

    // To avoid auto-casting during '==' we convert $element['#value'] and
    // $element['#return_value'] to strings. It will prevent wrong true-checking
    // for both cases: 0 == 'string' and 'string' == 0, this will occur because
    // all numeric array values will be integers and all submitted values will
    // be strings. Array values are never valid for radios and are skipped. To
    // account for FALSE and empty string values in the #return_value, we will
    // consider any #value that evaluates to empty to be the same as any
    // #return_value that evaluates to empty.
    if (isset($element['#return_value']) && $element['#value'] !== FALSE && !is_array($element['#value']) && (empty($element['#value']) && empty($element['#return_value']) || (string) $element['#value'] === (string) $element['#return_value'])) {
      $element['#attributes']['checked'] = 'checked';
    }
    static::setAttributes($element, [
      'form-radio',
    ]);
    return $element;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
DependencySerializationTrait::$_entityStorages	protected	property	An array of entity type IDs keyed by the property name of their storages.
DependencySerializationTrait::$_serviceIds	protected	property	An array of service IDs keyed by property name used for serialization.
DependencySerializationTrait::__sleep	public	function		1
DependencySerializationTrait::__wakeup	public	function		2
FormElement::processAutocomplete	public static	function	Adds autocomplete functionality to elements.
FormElement::processPattern	public static	function	#process callback for #pattern form element property.
FormElement::validatePattern	public static	function	#element_validate callback for #pattern form element property.
FormElement::valueCallback	public static	function	Determines how user input is mapped to an element's #value property. Overrides FormElementInterface::valueCallback	15
MessengerTrait::$messenger	protected	property	The messenger.	29
MessengerTrait::messenger	public	function	Gets the messenger.	29
MessengerTrait::setMessenger	public	function	Sets the messenger.
PluginBase::$configuration	protected	property	Configuration information passed into the plugin.	1
PluginBase::$pluginDefinition	protected	property	The plugin implementation definition.	1
PluginBase::$pluginId	protected	property	The plugin_id.
PluginBase::DERIVATIVE_SEPARATOR		constant	A string which is used to separate base plugin IDs from the derivative ID.
PluginBase::getBaseId	public	function	Gets the base_plugin_id of the plugin instance. Overrides DerivativeInspectionInterface::getBaseId
PluginBase::getDerivativeId	public	function	Gets the derivative_id of the plugin instance. Overrides DerivativeInspectionInterface::getDerivativeId
PluginBase::getPluginDefinition	public	function	Gets the definition of the plugin implementation. Overrides PluginInspectionInterface::getPluginDefinition	3
PluginBase::getPluginId	public	function	Gets the plugin_id of the plugin instance. Overrides PluginInspectionInterface::getPluginId
PluginBase::isConfigurable	public	function	Determines if the plugin is configurable.
PluginBase::__construct	public	function	Constructs a \Drupal\Component\Plugin\PluginBase object.	92
Radio::getInfo	public	function	Returns the element properties for this element. Overrides ElementInterface::getInfo
Radio::preRenderRadio	public static	function	Prepares a #type 'radio' render element for input.html.twig.
RenderElement::preRenderAjaxForm	public static	function	Adds Ajax information about an element to communicate with JavaScript.
RenderElement::preRenderGroup	public static	function	Adds members of this group as actual elements for rendering.
RenderElement::processAjaxForm	public static	function	Form element processing handler for the #ajax form property.	1
RenderElement::processGroup	public static	function	Arranges elements into groups.
RenderElement::setAttributes	public static	function	Sets a form element's class attribute. Overrides ElementInterface::setAttributes
StringTranslationTrait::$stringTranslation	protected	property	The string translation service.	1
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.