class FirstPage extends StatelessWidget {
  static const String routeName = '/first-page';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Container(
            child: Center(
                child: GestureDetector(
                    onTap: () => Navigator.pushNamed(context, SecondPage.routeName),
                    child: Text('Go to second page!'),
                ),
            ),
        ),
    );
  }
}

class SecondPage extends StatelessWidget {
  static const String routeName = '/second-page';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Container(
            child: Center(
                child: GestureDetector(
                    onTap: () => Navigator.pop(),
                    child: Text('Go to first page!'),
                ),
            ),
        ),
    );
  }
}