class Marquee in Examples for Developers 8

Same name and namespace in other branches

3.x modules/render_example/src/Element/Marquee.php \Drupal\render_example\Element\Marquee

Provides a marquee render element.

New render element types are defined as plugins. They live in the Drupal\{module_name}\Element namespace and implement \Drupal\Core\Render\Element\ElementInterface. They are annotated with either \Drupal\Core\Render\Annotation\RenderElement or \Drupal\Core\Render\Annotation\FormElement. And extend either the \Drupal\Core\Render\Element\RenderElement, or \Drupal\Core\Render\Element\FormElement base classes.

In the annotation below we define the string "marquee" as the ID for this plugin. That will also be the value used for the '#type' property in a render array. For example:

$build['awesome'] = [
  '#type' => 'marquee',
  '#content' => 'Whoa cools, a marquee!',
];

View an example of this custom element in use in \Drupal\render_example\Controller\RenderExampleController::arrays().

Plugin annotation

@RenderElement("marquee");

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\render_example\Element\Marquee

Expanded class hierarchy of Marquee

File

render_example/src/Element/Marquee.php, line 37

Namespace

Drupal\render_example\Element

View source

class Marquee extends RenderElement {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {

    // Returns an array of default properties that will be merged with any
    // properties defined in a render array when using this element type.
    // You can use any standard render array property here, and you can also
    // custom properties that are specific to your new element type.
    return [
      // See render_example_theme() where this new theme hook is declared.
      '#theme' => 'render_example_marquee',
      // Define a default #pre_render method. We will use this to handle
      // additional processing for the custom attributes we add below.
      '#pre_render' => [
        [
          self::class,
          'preRenderMarquee',
        ],
      ],
      // This is a custom property for our element type. We set it to blank by
      // default. The expectation is that a user will add the content that they
      // would like to see inside the marquee tag. This custom property is
      // accounted for in the associated template file.
      '#content' => '',
      '#attributes' => [
        'direction' => 'left',
        'loop' => -1,
        'scrollamount' => 'random',
      ],
    ];
  }

  /**
   * Pre-render callback; Process custom attribute options.
   *
   * @param array $element
   *   The renderable array representing the element with '#type' => 'marquee'
   *   property set.
   *
   * @return array
   *   The passed in element with changes made to attributes depending on
   *   context.
   */
  public static function preRenderMarquee(array $element) {

    // Normal attributes for a <marquee> tag do not include a 'random' option
    // for scroll amount. Our marquee element type does though. So we use this
    // #pre_render callback to check if the element was defined with the value
    // 'random' for the scrollamount attribute, and if so replace the string
    // with a random number.
    if ($element['#attributes']['scrollamount'] == 'random') {
      $element['#attributes']['scrollamount'] = abs(rand(1, 50));
    }
    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
Marquee::getInfo	public	function	Returns the element properties for this element. Overrides ElementInterface::getInfo
Marquee::preRenderMarquee	public static	function	Pre-render callback; Process custom attribute options.
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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