app_flow.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Splash(),
      routes: {
        '/login': (_) => Login(),
        '/home': (_) => Home(),
      },
    );
  }
}

class Splash extends StatefulWidget {
  @override
  _SplashState createState() => _SplashState();
}

class _SplashState extends State<Splash> {
  @override
  void initState() {
    super.initState();
    Future.delayed(Duration(seconds: 1), () {
      final loggedIn = true;
      if (loggedIn)
        Navigator.pushReplacementNamed(context, '/home');
      else
        Navigator.pushReplacementNamed(context, '/login');
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.white,
        child: Center(child: Text('Welcome')),
      ),
    );
  }
}

class Login extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Login', style: Theme.of(context).textTheme.headline4),
      ),
    );
  }
}

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home', style: Theme.of(context).textTheme.headline4),
      ),
    );
  }
}