How should I manage login page in flutter app - flutter

Question

I am making an app which starts with a splash screen.
What I want is if the user signing for the first time it should redirect to overboarding screen.For that I have used shared preferences and stored a value to check if the user is new or not.And from overbearing it should go to login page after login it will check the user data exists or not. And in normal case after splash it should redirect to home screen.My code is working. But the problem is I don't know how to arrange it.
Main.dart -> (check logged in or not ) -> (if already logged in)Home.dart -> (else check first time login or not)-> (if first time login then)Onboarding Screen From there Login screen ->else Login Screen
If you need any more information just ask me
This is the code from main.dart
return SplashScreen.navigate(
name: 'assets/splash.flr',
next: (context) {
return AuthService().handleAuth();
},
startAnimation: 'Untitled',
until: () => Future.delayed(Duration(seconds: 4)),
backgroundColor: Colors.white,
);
This is AuthService().handleAuth() code
handleAuth() {
return StreamBuilder(
stream: FirebaseAuth.instance.onAuthStateChanged,
builder: (context, snapshot) {
if (snapshot.hasData) {
Navigator.maybePop(context);
SharedPrefFunction().saveLoginPreference();
return CheckUser();
}
else{
return LoginScreen();}
});
}
This is the onboarding code
onTap: () {
Navigator.of(context)
.pushReplacementNamed(LoginScreen.loginRoute);
},
I want to go to AuthService().handleAuth() from onboarding.
How can I reach there from Onboarding screen or suggest me something better.

Answer 1

In your main.dart
bool loggedIn = false;
#override
void initState() {
super.initState();
isUserLoggedIn();
}
void isUserLoggedIn() async {
_loggedIn = await SharedPrefFunction().getLoginPreference()
setState(() => loggedIn = _loggedIn);
}
Widget build(BuildContext context) {
loggedIn ? LoginScreen() : SplashScreen()
}