How to push to page when async function is finished? - flutter

Question

Im developing a app that when the user enters the first screen is a loading screen where initialize somethings from the Provider, the user cant input anything in this screen, when the loading finishes i want to push a new screen without the user "clicking" for it.
In this code, im actually given a delay of 3 seconds for the _login.getStoredEmail() to run and set a variable inside LoginController which in the next screen i consume, but of course this wont work everytime, eventually will break.
class GeneralSplashScreen extends StatefulWidget {
#override
_GeneralSplashScreenState createState() => _GeneralSplashScreenState();
}
class _GeneralSplashScreenState extends State<GeneralSplashScreen> {
#override
void initState() {
Future.delayed(
Duration(
seconds: 3,
),
() {
Navigator.pushReplacementNamed(context, kRoutes.login);
},
);
super.initState();
}
#override
void dispose() {
super.dispose();
}
#override
Widget build(BuildContext context) {
final LoginController _login = Provider.of<LoginController>(context);
_login.getStoredEmail();
return Scaffold(
body: Padding(
padding: const EdgeInsets.symmetric(horizontal: 60),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
Image.asset(
'lib/assets/images/logo.png',
fit: BoxFit.contain,
),
Text(
"Business Mananger",
textAlign: TextAlign.end,
style: TextStyle(
fontFamily: kFontFamily.montserrat,
fontSize: 10,
),
),
LoadingBar(),
],
),
),
);
}
}

Answer 1

Navigate to a different screen inside the initState() method.
initState() {
initializeAndNavigate()
}
initializeAndNavigate() async {
await initializeSomething();
Navigator.of(context) ...
}

Answer 2

Declare initState
Future _future;
#override
void initState() {
// TODO: implement initState
super.initState();
_future = doStuff();
}
Use FutureBuilder
FutureBuilder(
future: _future,
builder: (_, dataSnapshot) {
if (dataSnapshot.connectionState == ConnectionState.waiting) {
return Center(child: CircularProgressIndicator()); // here add loading screen
} else {
return Dashboard();
}
},
)