class AnnounceCommand in Drupal 9

AJAX command for a JavaScript Drupal.announce() call.

Developers should be extra careful if this command and \Drupal\Core\Ajax\MessageCommand are included in the same response. By default, MessageCommand will also call Drupal.announce() and announce the message to the screen reader (unless the option to suppress announcements is passed to the constructor). Manual testing with a screen reader is strongly recommended.

Hierarchy

• class \Drupal\Core\Ajax\AnnounceCommand implements CommandInterface, CommandWithAttachedAssetsInterface

See also

\Drupal\Core\Ajax\MessageCommand

Related topics

Ajax API

Overview for Drupal's Ajax API.

3 files declare their use of AnnounceCommand

AjaxCommandsTest.php in core/tests/Drupal/Tests/Core/Ajax/AjaxCommandsTest.php

ajax_forms_test.module in core/modules/system/tests/modules/ajax_forms_test/ajax_forms_test.module

Simpletest mock module for Ajax forms testing.

MediaLibraryWidget.php in core/modules/media_library/src/Plugin/Field/FieldWidget/MediaLibraryWidget.php

File

core/lib/Drupal/Core/Ajax/AnnounceCommand.php, line 21

Namespace

Drupal\Core\Ajax

class AnnounceCommand implements CommandInterface, CommandWithAttachedAssetsInterface {

  /**
   * The assertive priority attribute value.
   *
   * @var string
   */
  const PRIORITY_ASSERTIVE = 'assertive';

  /**
   * The polite priority attribute value.
   *
   * @var string
   */
  const PRIORITY_POLITE = 'polite';

  /**
   * The text to be announced.
   *
   * @var string
   */
  protected $text;

  /**
   * The priority that will be used for the announcement.
   *
   * @var string
   */
  protected $priority;

  /**
   * Constructs an AnnounceCommand object.
   *
   * @param string $text
   *   The text to be announced.
   * @param string|null $priority
   *   (optional) The priority that will be used for the announcement. Defaults
   *   to NULL which will not set a 'priority' in the response sent to the
   *   client and therefore the JavaScript Drupal.announce() default of 'polite'
   *   will be used for the message.
   */
  public function __construct($text, $priority = NULL) {
    $this->text = $text;
    $this->priority = $priority;
  }

  /**
   * {@inheritdoc}
   */
  public function render() {
    $render = [
      'command' => 'announce',
      'text' => $this->text,
    ];
    if ($this->priority !== NULL) {
      $render['priority'] = $this->priority;
    }
    return $render;
  }

  /**
   * {@inheritdoc}
   */
  public function getAttachedAssets() {
    $assets = new AttachedAssets();
    $assets
      ->setLibraries([
      'core/drupal.announce',
    ]);
    return $assets;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
AnnounceCommand::$priority	protected	property	The priority that will be used for the announcement.
AnnounceCommand::$text	protected	property	The text to be announced.
AnnounceCommand::getAttachedAssets	public	function	Gets the attached assets. Overrides CommandWithAttachedAssetsInterface::getAttachedAssets
AnnounceCommand::PRIORITY_ASSERTIVE		constant	The assertive priority attribute value.
AnnounceCommand::PRIORITY_POLITE		constant	The polite priority attribute value.
AnnounceCommand::render	public	function	Return an array to be run through json_encode and sent to the client. Overrides CommandInterface::render
AnnounceCommand::__construct	public	function	Constructs an AnnounceCommand object.