class 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'] = [
    '#type' => 'button',
    '#value' => $this->t('Preview'),
];

Hierarchy

class \Drupal\Component\Plugin\PluginBase implements \Drupal\Component\Plugin\PluginInspectionInterface, \Drupal\Component\Plugin\DerivativeInspectionInterface
- class \Drupal\Core\Plugin\PluginBase extends \Drupal\Component\Plugin\PluginBase uses \Drupal\Core\StringTranslation\StringTranslationTrait, \Drupal\Core\DependencyInjection\DependencySerializationTrait, \Drupal\Core\Messenger\MessengerTrait
  - class \Drupal\Core\Render\Element\RenderElementBase extends \Drupal\Core\Plugin\PluginBase implements \Drupal\Core\Render\Element\ElementInterface
    - class \Drupal\Core\Render\Element\FormElementBase extends \Drupal\Core\Render\Element\RenderElementBase implements \Drupal\Core\Render\Element\FormElementInterface
      - class \Drupal\Core\Render\Element\Button extends \Drupal\Core\Render\Element\FormElementBase

Expanded class hierarchy of Button

File

core/lib/Drupal/Core/Render/Element/Button.php, line 32

Namespace

Drupal\Core\Render\Element

View source

class Button extends FormElementBase {
    
    /**
     * {@inheritdoc}
     */
    public function getInfo() {
        $class = static::class;
        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

Title Sort descending	Modifiers	Object type	Summary	Overriden Title	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.
FormElementBase::processAutocomplete	public static	function	Adds autocomplete functionality to elements.		1
FormElementBase::processPattern	public static	function	#process callback for #pattern form element property.		1
FormElementBase::validatePattern	public static	function	#element_validate callback for #pattern form element property.		1
FormElementBase::valueCallback	public static	function	Determines how user input is mapped to an element's #value property.	Overrides FormElementInterface::valueCallback	17
PluginInspectionInterface::getPluginDefinition	public	function	Gets the definition of the plugin implementation.		5
PluginInspectionInterface::getPluginId	public	function	Gets the plugin ID of the plugin instance.		2
RenderElementBase::preRenderAjaxForm	public static	function	Adds Ajax information about an element to communicate with JavaScript.		2
RenderElementBase::preRenderGroup	public static	function	Adds members of this group as actual elements for rendering.		2
RenderElementBase::processAjaxForm	public static	function	Form element processing handler for the #ajax form property.		3
RenderElementBase::processGroup	public static	function	Arranges elements into groups.		2
RenderElementBase::setAttributes	public static	function	Sets a form element's class attribute.	Overrides ElementInterface::setAttributes	2

class Button

Hierarchy

See also

File

Namespace

Members