class Button in Drupal 8

Same name and namespace in other branches

9 core/lib/Drupal/Core/Render/Element/Button.php \Drupal\Core\Render\Element\Button

Provides an action button form element.

When the button is pressed, the form will be submitted to Drupal, where it is validated and rebuilt. The submit handler is not invoked.

Properties:

#limit_validation_errors: An array of form element keys that will block form submission when validation for these elements or any child elements fails. Specify an empty array to suppress all form validation errors.
#value: The text to be shown on the button.

Usage Example:

$form['actions']['preview'] = array(
  '#type' => 'button',
  '#value' => $this
    ->t('Preview'),
);

Plugin annotation

@FormElement("button");

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\Button

Expanded class hierarchy of Button

File

core/lib/Drupal/Core/Render/Element/Button.php, line 33

Namespace

Drupal\Core\Render\Element

View source

class Button extends FormElement {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = get_class($this);
    return [
      '#input' => TRUE,
      '#name' => 'op',
      '#is_button' => TRUE,
      '#executes_submit_callback' => FALSE,
      '#limit_validation_errors' => FALSE,
      '#process' => [
        [
          $class,
          'processButton',
        ],
        [
          $class,
          'processAjaxForm',
        ],
      ],
      '#pre_render' => [
        [
          $class,
          'preRenderButton',
        ],
      ],
      '#theme_wrappers' => [
        'input__submit',
      ],
    ];
  }

  /**
   * Processes a form button element.
   */
  public static function processButton(&$element, FormStateInterface $form_state, &$complete_form) {

    // If this is a button intentionally allowing incomplete form submission
    // (e.g., a "Previous" or "Add another item" button), then also skip
    // client-side validation.
    if (isset($element['#limit_validation_errors']) && $element['#limit_validation_errors'] !== FALSE) {
      $element['#attributes']['formnovalidate'] = 'formnovalidate';
    }
    return $element;
  }

  /**
   * Prepares a #type 'button' render element for input.html.twig.
   *
   * @param array $element
   *   An associative array containing the properties of the element.
   *   Properties used: #attributes, #button_type, #name, #value. The
   *   #button_type property accepts any value, though core themes have CSS that
   *   styles the following button_types appropriately: 'primary', 'danger'.
   *
   * @return array
   *   The $element with prepared variables ready for input.html.twig.
   */
  public static function preRenderButton($element) {
    $element['#attributes']['type'] = 'submit';
    Element::setAttributes($element, [
      'id',
      'name',
      'value',
    ]);
    $element['#attributes']['class'][] = 'button';
    if (!empty($element['#button_type'])) {
      $element['#attributes']['class'][] = 'button--' . $element['#button_type'];
    }
    $element['#attributes']['class'][] = 'js-form-submit';
    $element['#attributes']['class'][] = 'form-submit';
    if (!empty($element['#attributes']['disabled'])) {
      $element['#attributes']['class'][] = 'is-disabled';
    }
    return $element;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Button::getInfo	public	function	Returns the element properties for this element. Overrides ElementInterface::getInfo	1
Button::preRenderButton	public static	function	Prepares a #type 'button' render element for input.html.twig.	1
Button::processButton	public static	function	Processes a form button element.
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
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.

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