contacts_events-8.x-1.x-dev/src/Routing/ViewsAdminRouteSubscriber.php

<?php

namespace Drupal\contacts_events\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

/**
 * Modifies routes to be considered 'admin routes'.
 */
class ViewsAdminRouteSubscriber extends RouteSubscriberBase {

  /**
   * {@inheritdoc}
   */
  protected function alterRoutes(RouteCollection $collection) {
    // Routes generated by views don't provide a way to set the '_admin_route'
    // option in the view, so we have to do it via subscriber.
    // @todo Remove this once Core provides a way to do this out of the box
    // which is supposedly coming in 8.9:
    // https://www.drupal.org/project/drupal/issues/2719797
    $routes = [
      'view.contacts_events_tickets.page_1',
      'view.contacts_events_tickets_statistics.page_1',
      'view.contacts_events_bookings_without_tickets.page_1',
      'view.contacts_events_childrens_tickets.page_1',
      'view.contacts_events_accommodation_summary.page_1',
      'view.contacts_events_booking_balances.balances',
      'view.contacts_events_booking_balances.refunds',
    ];

    foreach ($routes as $route_id) {
      if ($route = $collection->get($route_id)) {
        $route->setOption('_admin_route', TRUE);
      }
    }
  }

}