getMediaLibraryState example

  protected function getMediaType(FormStateInterface $form_state) {
    if ($this->mediaType) {
      return $this->mediaType;
    }

    $state = $this->getMediaLibraryState($form_state);
    $selected_type_id = $state->getSelectedTypeId();
    $this->mediaType = $this->entityTypeManager->getStorage('media_type')->load($selected_type_id);

    if (!$this->mediaType) {
      throw new \InvalidArgumentException("The '$selected_type_id' media type does not exist.");
    }

    return $this->mediaType;
  }

  /** * {@inheritdoc} */

  /** * {@inheritdoc} */
  protected function buildInputElement(array $form, FormStateInterface $form_state) {
    // Create a file item to get the upload validators.     $media_type = $this->getMediaType($form_state);
    $item = $this->createFileItem($media_type);

    /** @var \Drupal\media_library\MediaLibraryState $state */
    $state = $this->getMediaLibraryState($form_state);
    if (!$state->hasSlotsAvailable()) {
      return $form;
    }

    $slots = $state->getAvailableSlots();

    // Add a container to group the input elements for styling purposes.     $form['container'] = [
      '#type' => 'container',
    ];

    

'#submit' => ['::addButtonSubmit'],
      // @todo Move validation in https://www.drupal.org/node/2988215       '#ajax' => [
        'callback' => '::updateFormCallback',
        'wrapper' => 'media-library-wrapper',
        // Add a fixed URL to post the form since AJAX forms are automatically         // posted to <current> instead of $form['#action'].         // @todo Remove when https://www.drupal.org/project/drupal/issues/2504115         // is fixed.         'url' => Url::fromRoute('media_library.ui'),
        'options' => [
          'query' => $this->getMediaLibraryState($form_state)->all() + [
            FormBuilderInterface::AJAX_FORM_REQUEST => TRUE,
          ],
        ],
      ],
    ];
    return $form;
  }

  /** * Validates the oEmbed URL. * * @param array $form * The complete form. * @param \Drupal\Core\Form\FormStateInterface $form_state * The current form state. */