main.dart

return MaterialApp(
  onGenerateRoute: (settings) {
    if (settings.name == '/information') {
      return PageRouteBuilder(
        pageBuilder: (context, animation1, animation2) => InformationScreen(),
        transitionDuration: Duration(seconds: 0),
      );
    } else if (settings.name == '/privacy') {
      return PageRouteBuilder(
        pageBuilder: (context, animation1, animation2) => PrivacySettings(),
        transitionDuration: Duration(seconds: 0),
      );
    } else if (settings.name == '/qrcode') {
      return PageRouteBuilder(
        pageBuilder: (context, animation1, animation2) => QRCodeReader(),
        transitionDuration: Duration(seconds: 0),
      );
    } else if (settings.name == '/auth') {
      return PageRouteBuilder(
        pageBuilder: (context, animation1, animation2) => AuthScreen(),
        transitionDuration: Duration(seconds: 0),
      );
    }
    return null;
  },
  title: 'Flutter Demo',
  theme: ...,
  home: ...
);