GlobalKey 사용 예

main.dart

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final navigatorKey = GlobalKey<NavigatorState>();   // 여기
    return MaterialApp(
      navigatorKey: navigatorKey, // 여기
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter Tutorial'),
        ),
        body: Home(),
        floatingActionButton: FloatingActionButton(onPressed: () {
          navigatorKey.currentState.push(MaterialPageRoute(builder: (context) => SecondRoute())); // 여기
        }),
      ),
    );
  }
}