if user is logged in or not check flutter
int main(){
runApp( YourApp() )
}
class YourApp extends StatelessWidget{
@override
Widget build(BuildContext context){
return FutureBuilder<FirebaseUser>(
future: FirebaseAuth.instance.currentUser(),
builder: (BuildContext context, AsyncSnapshot<FirebaseUser> snapshot){
if (snapshot.hasData){
FirebaseUser user = snapshot.data; // this is your user instance
/// is because there is user already logged
return MainScreen();
}
/// other way there is no user logged.
return LoginScreen();
}
);
}
}