tile.dart

class Tile extends StatelessWidget {
  final VoidCallback onTap; //<--new parameter

  const Tile({Key key, this.height, this.state, this.onTap}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: double.infinity,
      height: height,
      child: GestureDetector(
        onTapDown: (_) => onTap(), //<-- call onTap
        child: Container(color: color),
      ),
    );
  }
  ...
}