routes.dart

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      initialRoute: '/',
      routes: {
        '/': (BuildContext context) => HomePage(),
        '/page1': (BuildContext context) => Page1(),
        '/page4': (BuildContext context) => Page4(),
      },
    );
  }
}