RearrangeFilter::buildForm

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

public function buildForm(array $form, FormStateInterface $form_state) {
  $view = $form_state->get('view');
  $display_id = $form_state->get('display_id');
  $type = 'filter';

  $types = ViewExecutable::getHandlerTypes();
  $executable = $view->getExecutable();
  if (!$executable->setDisplay($display_id)) {
    $form['markup'] = array('#markup' => $this->t('Invalid display id @display', array('@display' => $display_id)));
    return $form;
  }
  $display = $executable->displayHandlers->get($display_id);
  $form['#title'] = Html::escape($display->display['display_title']) . ': ';
  $form['#title'] .= $this->t('Rearrange @type', array('@type' => $types[$type]['ltitle']));
  $form['#section'] = $display_id . 'rearrange-item';

  if ($display->defaultableSections($types[$type]['plural'])) {
    $section = $types[$type]['plural'];
    $form_state->set('section', $section);
    views_ui_standard_display_dropdown($form, $form_state, $section);
  }

  if (!empty($view->form_cache)) {
    $groups = $view->form_cache['groups'];
    $handlers = $view->form_cache['handlers'];
  }
  else {
    $groups = $display->getOption('filter_groups');
    $handlers = $display->getOption($types[$type]['plural']);
  }
  $count = 0;

  // Get relationship labels
  $relationships = array();
  foreach ($display->getHandlers('relationship') as $id => $handler) {
    $relationships[$id] = $handler->adminLabel();
  }

  $group_options = array();

  /**
   * Filter groups is an array that contains:
   * array(
   *   'operator' => 'and' || 'or',
   *   'groups' => array(
   *     $group_id => 'and' || 'or',
   *   ),
   * );
   */

  $grouping = count(array_keys($groups['groups'])) > 1;

  $form['filter_groups']['#tree'] = TRUE;
  $form['filter_groups']['operator'] = array(
    '#type' => 'select',
    '#options' => array(
      'AND' => $this->t('And'),
      'OR' => $this->t('Or'),
    ),
    '#default_value' => $groups['operator'],
    '#attributes' => array(
      'class' => array('warning-on-change'),
    ),
    '#title' => $this->t('Operator to use on all groups'),
    '#description' => $this->t('Either "group 0 AND group 1 AND group 2" or "group 0 OR group 1 OR group 2", etc'),
    '#access' => $grouping,
  );

  $form['remove_groups']['#tree'] = TRUE;

  foreach ($groups['groups'] as $id => $group) {
    $form['filter_groups']['groups'][$id] = array(
      '#title' => $this->t('Operator'),
      '#type' => 'select',
      '#options' => array(
        'AND' => $this->t('And'),
        'OR' => $this->t('Or'),
      ),
      '#default_value' => $group,
      '#attributes' => array(
        'class' => array('warning-on-change'),
      ),
    );

    $form['remove_groups'][$id] = array(); // to prevent a notice
    if ($id != 1) {
      $form['remove_groups'][$id] = array(
        '#type' => 'submit',
        '#value' => $this->t('Remove group @group', array('@group' => $id)),
        '#id' => "views-remove-group-$id",
        '#attributes' => array(
          'class' => array('views-remove-group'),
        ),
        '#group' => $id,
      );
    }
    $group_options[$id] = $id == 1 ? $this->t('Default group') : $this->t('Group @group', array('@group' => $id));
    $form['#group_renders'][$id] = array();
  }

  $form['#group_options'] = $group_options;
  $form['#groups'] = $groups;
  // We don't use getHandlers() because we want items without handlers to
  // appear and show up as 'broken' so that the user can see them.
  $form['filters'] = array('#tree' => TRUE);
  foreach ($handlers as $id => $field) {
    // If the group does not exist, move the filters to the default group.
    if (empty($field['group']) || empty($groups['groups'][$field['group']])) {
      $field['group'] = 1;
    }

    $handler = $display->getHandler($type, $id);
    if ($grouping && $handler && !$handler->canGroup()) {
      $field['group'] = 'ungroupable';
    }

    // If not grouping and the handler is set ungroupable, move it back to
    // the default group to prevent weird errors from having it be in its
    // own group:
    if (!$grouping && $field['group'] == 'ungroupable') {
      $field['group'] = 1;
    }

    // Place this item into the proper group for rendering.
    $form['#group_renders'][$field['group']][] = $id;

    $form['filters'][$id]['weight'] = array(
      '#title' => t('Weight for @id', array('@id' => $id)),
      '#title_display' => 'invisible',
      '#type' => 'textfield',
      '#default_value' => ++$count,
      '#size' => 8,
    );
    $form['filters'][$id]['group'] = array(
      '#title' => t('Group for @id', array('@id' => $id)),
      '#title_display' => 'invisible',
      '#type' => 'select',
      '#options' => $group_options,
      '#default_value' => $field['group'],
      '#attributes' => array(
        'class' => array('views-region-select', 'views-region-' . $id),
      ),
      '#access' => $field['group'] !== 'ungroupable',
    );

    if ($handler) {
      $name = $handler->adminLabel() . ' ' . $handler->adminSummary();
      if (!empty($field['relationship']) && !empty($relationships[$field['relationship']])) {
        $name = '(' . $relationships[$field['relationship']] . ') ' . $name;
      }

      $form['filters'][$id]['name'] = array(
        '#markup' => $name,
      );
    }
    else {
      $form['filters'][$id]['name'] = array('#markup' => $this->t('Broken field @id', array('@id' => $id)));
    }
    $form['filters'][$id]['removed'] = array(
      '#title' => t('Remove @id', array('@id' => $id)),
      '#title_display' => 'invisible',
      '#type' => 'checkbox',
      '#id' => 'views-removed-' . $id,
      '#attributes' => array('class' => array('views-remove-checkbox')),
      '#default_value' => 0,
    );
  }

  $view->getStandardButtons($form, $form_state, 'views_ui_rearrange_filter_form');
  $form['actions']['add_group'] = array(
    '#type' => 'submit',
    '#value' => $this->t('Create new filter group'),
    '#id' => 'views-add-group',
    '#group' => 'add',
    '#attributes' => array(
      'class' => array('views-add-group'),
    ),
    '#ajax' => ['url' => NULL],
  );

  return $form;
}