How to navigate different page after async method return response - dart

Question

I have a screen App in which i have onGenerateRoute property of MaterialApp. In the routes method i make an api call and once i get the response i want to let user navigate to login screen
I tried calling my widget Login inside .then() function
class App extends StatelessWidget {
Widget build(BuildContext context) {
return AppBlocProvider(
child: LoginBlocProvider(
child: MaterialApp(
onGenerateRoute: routes,
),
),
);
}
Route routes(RouteSettings settings) {
print(settings.name);
switch (settings.name) {
case '/':
return MaterialPageRoute(builder: (context) {
//HERE I AM MAKING API CALL
final appBloc = AppBlocProvider.of(context);
appBloc.verifyUser().then((response) {
//HERE ONCE I GET THE RESPONSE I WANT TO NAVIGATE USER TO
//lOGIN ACTIVITY
print('called');
return Login();
});
return AppBlocProvider(
child: Center(child: CircularProgressIndicator()),
);
});
break;
case '/Login':
return MaterialPageRoute(builder: (BuildContext context) {
return Login();
});
break;
case '/HomeScreen':
return MaterialPageRoute(builder: (BuildContext context) {
return Home();
});
break;
}
return MaterialPageRoute(builder: (context) {
print('returned null');
});
}
api call get successful and even .then() method executes but login screen doesn't appear

Answer 1

The reason return Login(); doesn't do anything was because another return has been executed already: return AppBlocProvider(child: Widget());
Similar to this sample, since a return has been already made, the other return won't do anything. The sample prints 'bar', and 'foo' was never printed using print(bar());.
void main() {
print(bar());
}
Future<String> foo() async{
await Future.delayed(Duration(seconds: 5));
return 'foo';
}
String bar(){
String txt = 'bar';
foo().then((String value){
print('Future finished: $value');
// Since print already got a String return,
// returning this value won't do anything
return value; // 'foo' won't be printed on main()
});
return txt;
}
You may want to consider moving the navigation inside Login and also display CircularProgressIndicator() there.