Provider : Looking up a deactivated widget's ancestor is unsafe - flutter

Question

Trying to get the value from provider, it works OK, but I get the error below. What i am doing wrong here?
#override
Widget build(BuildContext context) {
String route = Provider.of<User>(context) == null ? Router.LOGIN : Router.HOME;
Future.delayed(const Duration(seconds: 2), () => Navigator.pushReplacementNamed(context, route));
return Scaffold(........
error
E/flutter (23058): [ERROR:flutter/shell/common/shell.cc(209)] Dart Error: Unhandled exception:
E/flutter (23058): Looking up a deactivated widget's ancestor is unsafe.
E/flutter (23058): At this point the state of the widget's element tree is no longer stable.
E/flutter (23058): To safely refer to a widget's ancestor in its dispose() method, save a reference to the ancestor by calling dependOnInheritedWidgetOfExactType() in the widget's didChangeDependencies() method.

Answer 1

The problem is not being able to await the navigator call. If you need to navigate to the correct page on build, then create an async method with no return type, then call the method in initState.
_checkUserExistsAndNavigate() async {
String route = Provider.of<User>(context) == null ? Router.login : Router.home;
await Future.delayed(seconds: 2), () => Navigator.pushReplacementNamed(context, route);
}
#initState(() {
_checkUserExistsAndNavigate();
super.initState();
}