flutter-architecture-expert

flutter_it Architecture Expert - App Structure & Patterns

What: Architecture guidance for Flutter apps using the flutter_it construction set (get_it + watch_it + command_it + listen_it).

App Startup

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  configureDependencies();  // Register all services (sync)
  runApp(MyApp());
}

// Splash screen waits for async services
class SplashScreen extends WatchingWidget {
  @override
  Widget build(BuildContext context) {
    final ready = allReady(
      onReady: (context) => Navigator.pushReplacement(context, mainRoute),
    );
    if (!ready) return CircularProgressIndicator();
    return MainApp();
  }
}

Pragmatic Flutter Architecture (PFA)

Three components: Services (external boundaries), Managers (business logic), Views (self-responsible UI).

• Services: Wrap ONE external aspect (REST API, database, OS service, hardware). Convert data from/to external formats (JSON). Do NOT change app state.
• Managers: Wrap semantically related business logic (UserManager, BookingManager). NOT ViewModels - don't map 1:1 to views. Provide Commands/ValueListenables for the UI. Use Services or other Managers.
• Views: Full pages or high-level widgets. Self-responsible - know what data they need. Read data from Managers via ValueListenables. Modify data through Managers, never directly through Services.

Project Structure (by feature, NOT by layer)

lib/
  _shared/                   # Shared across features (prefix _ sorts to top)
    services/                # Cross-feature services
    widgets/                 # Reusable widgets
    models/                  # Shared domain objects
  features/
    auth/
      pages/                 # Full-screen views
      widgets/               # Feature-specific widgets
      manager/               # AuthManager, commands
      model/                 # User, UserProxy, DTOs
      services/              # AuthApiService
    chat/
      pages/
      widgets/
      manager/
      model/
      services/
  locator.dart               # DI configuration (get_it registrations)