flutter_nav_tut

.\lib\newPage.dart

import 'package:flutter_app_nav_test/getBackString.dart';
// ...
class _NewPageState extends State<NewPage> {
  // ...
  String status = "No string here";
 
  void clickGetBackString() async {
    status = await Navigator.push<String>(
        context,
        MaterialPageRoute(
            builder: (BuildContext context) => GetBackStringPage()));
  }
  // ...  
  }
}