main_with_route_data_handler.dart

MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        initialRoute: '/',
        routes: {
          '/': (context) => MyHomePage(),
          '/profile': (context) => Profile(),
        },
        onGenerateRoute: (settings) {
          if (settings.name == '/detailed-profile') {
            ProfileArguments args = settings.arguments;
            return MaterialPageRoute(
                builder: (context) => DetailedProfile(
                      name: args.name,
                      email: args.email,
                    ));
          } 
          return null;
        });
  }
}