ReorderDisplays::buildForm

public ReorderDisplays::buildForm(array $form, FormStateInterface $form_state)

public function buildForm(array $form, FormStateInterface $form_state) {
  /** @var $view \Drupal\views\ViewEntityInterface */
  $view = $form_state->get('view');
  $display_id = $form_state->get('display_id');

  $form['#title'] = $this->t('Reorder displays');
  $form['#section'] = 'reorder';
  $form['#action'] = $this->url('views_ui.form_reorder_displays', [
    'js' => 'nojs',
    'view' => $view->id(),
    'display_id' => $display_id,
  ]);
  $form['view'] = array(
    '#type' => 'value',
    '#value' => $view
  );

  $displays = $view->get('display');
  $count = count($displays);

  // Sort the displays.
  uasort($displays, function($display1, $display2) {
    if ($display1['position'] != $display2['position']) {
      return $display1['position'] < $display2['position'] ? -1 : 1;
    }
    return 0;
  });

  $form['displays'] = array(
    '#type' => 'table',
    '#id' => 'reorder-displays',
    '#header' => array($this->t('Display'), $this->t('Weight'), $this->t('Remove')),
    '#empty' => $this->t('No displays available.'),
    '#tabledrag' => array(
      array(
        'action' => 'order',
        'relationship' => 'sibling',
        'group' => 'weight',
      )
    ),
    '#tree' => TRUE,
    '#prefix' => '<div class="scroll" data-drupal-views-scroll>',
    '#suffix' => '</div>',
  );

  foreach ($displays as $id => $display) {
    $form['displays'][$id] = array(
      '#display' => $display,
      '#attributes' => array(
        'id' => 'display-row-' . $id,
      ),
      '#weight' => $display['position'],
    );

    // Only make row draggable if it's not the default display.
    if ($id !== 'default') {
      $form['displays'][$id]['#attributes']['class'][] = 'draggable';
    }

    $form['displays'][$id]['title'] = array(
      '#markup' => $display['display_title'],
    );

    $form['displays'][$id]['weight'] = array(
      '#type' => 'weight',
      '#value' => $display['position'],
      '#delta' => $count,
      '#title' => $this->t('Weight for @display', array('@display' => $display['display_title'])),
      '#title_display' => 'invisible',
      '#attributes' => array(
        'class' => array('weight'),
      ),
    );

    $form['displays'][$id]['removed'] = array(
      'checkbox' => array(
        '#title' => t('Remove @id', array('@id' => $id)),
        '#title_display' => 'invisible',
        '#type' => 'checkbox',
        '#id' => 'display-removed-' . $id,
        '#attributes' => array(
          'class' => array('views-remove-checkbox'),
        ),
        '#default_value' => !empty($display['deleted']),
      ),
      'link' => array(
        '#type' => 'link',
        '#title' => SafeMarkup::format('<span>@text</span>', array('@text' => $this->t('Remove'))),
        '#url' => Url::fromRoute('<none>'),
        '#attributes' => array(
          'id' => 'display-remove-link-' . $id,
          'class' => array('views-button-remove', 'display-remove-link'),
          'alt' => $this->t('Remove this display'),
          'title' => $this->t('Remove this display'),
        ),
      ),
      '#access' => ($id !== 'default'),
    );

    if (!empty($display['deleted'])) {
      $form['displays'][$id]['deleted'] = array(
        '#type' => 'value',
        '#value' => TRUE,
      );

      $form['displays'][$id]['#attributes']['class'][] = 'hidden';
    }

  }

  $view->getStandardButtons($form, $form_state, 'views_ui_reorder_displays_form');

  return $form;
}