flutter-rp-example/lib/pages/login.dart

import 'package:flutter/material.dart';

import '../widgets/login_screen.dart';

class LoginPage extends Page {
  final VoidCallback onLogin;

  const LoginPage({required this.onLogin})
      : super(key: const ValueKey('LoginPage'));

  @override
  Route createRoute(BuildContext context) {
    return MaterialPageRoute(
      settings: this,
      builder: (BuildContext context) => LoginScreen(onLogin: onLogin),
    );
  }
}