public function indexAction()
{
$source = new Entity('OjsAdminBundle:AdminAnnouncement');
$grid = $this->get('grid')->setSource($source);
$gridAction = $this->get('grid_action');
$actionColumn = new ActionsColumn("actions", 'actions');
$rowAction[] = $gridAction->showAction('ojs_admin_announcement_show', 'id');
$rowAction[] = $gridAction->editAction('ojs_admin_announcement_edit', 'id');
$rowAction[] = $gridAction->deleteAction('ojs_admin_announcement_delete', 'id');
$actionColumn->setRowActions($rowAction);
$grid->addColumn($actionColumn);
return $grid->getGridResponse('OjsAdminBundle:AdminAnnouncement:index.html.twig', ['grid' => $grid]);
}