1. override
void handleEvent(PointerEvent event, HitTestEntry entry)

Override this method to handle pointer events that hit this render object.

For RenderBox objects, the entry argument is a BoxHitTestEntry. From this object you can determine the PointerDownEvent's position in local coordinates. (This is useful because PointerEvent.position is in global coordinates.)

If you override this, consider calling debugHandleEvent as follows, so that you can support debugPaintPointersEnabled:

@override
void handleEvent(PointerEvent event, HitTestEntry entry) {
  assert(debugHandleEvent(event, entry));
  // ... handle the event ...
}

Source 

// TODO(ianh): Fix the type of the argument here once https://github.com/dart-lang/sdk/issues/25232 is fixed
@override
void handleEvent(PointerEvent event, HitTestEntry entry) {
  super.handleEvent(event, entry);
}