code: public void scanControllers()
      {
          for (GVRCursorController controller : getCursorControllers())
          {
              if (!controllers.contains(controller))
              {
                  controllers.add(controller);
              }
              if (controller.isConnected())
              {
                  addCursorController(controller);
              }
          }
      }
docs: Emit "onCursorControllerAdded" events to controller listeners
  for all connected controllers.
  <p>
  To connect with controllers, the application must add a {@link ICursorControllerListener}
  to listen for onCursorControllerAdded and onCursorControllerRemoved events
  and then call this function to emit the events.
  An event is sent immediately if the controller is actually ready
  and connected. If the controller connects later, the event
  will occur later and will not be sent from this function
  (this can happen with Bluetooth devices).
  @see ICursorControllerListener
  @see #selectController()