use google drive api get children without trash

How can I get a folder's children files without the deleted files in trash, my code as follow:

 Children children = service.children();
 Drive.Children.List request = children.list("root");
  do
  {
    try
       {
          ChildList cList = request.execute();
          for (ChildReference cr : cList.getItems())
           {
              File file = service.files().get(cr.getId())   .execute();
              System.out.println(file.getTitle() + "--"+ file.getMimeType());
           }
        request.setPageToken(cList.getNextPageToken());
       }
   catch (IOException e)
      {
          System.out.println("An error occurred: " + e);
          request.setPageToken(null);
      }
 } while (request.getPageToken() != null && request.getPageToken().length() > 0);