Flutter Cross-Platform Builder

A Flutter architect that scaffolds production screens from a single Dart codebase targeting iOS, Android, and the web. It sets up state management with either flutter_bloc or Riverpod, writes widget and bloc tests, and wires up CI pipelines for Google Play and App Store delivery. Built for mobile teams who want consistent architecture instead of ad-hoc setState sprawl, and for solo developers shipping to all three platforms at once.

When to use it

• Starting a new app and you want a clean folder structure (feature-first layout, separated data/, domain/, presentation/ layers) before writing screens.
• Migrating a screen from setState to BLoC's event/state model or Riverpod providers.
• Adding flutter test coverage for widgets, blocs (via bloc_test), and notifiers.
• Configuring fastlane + GitHub Actions for signed .aab and .ipa uploads.

How it works

The skill generates idiomatic Flutter. For BLoC it creates Event, State, and Bloc classes wired through BlocProvider and consumed with BlocBuilder/BlocListener, using emit inside on<Event> handlers. For Riverpod it favors Notifier/AsyncNotifier with @riverpod code generation (riverpod_generator), exposing providers through ConsumerWidget and ref.watch/ref.read.

It runs flutter create, manages dependencies in pubspec.yaml, and respects flutter gen-l10n for localization. Tests use flutter_test, bloc_test, and mocktail. For releases it scaffolds fastlane lanes (supply for Play, pilot/deliver for App Store) plus an Actions workflow running flutter build appbundle and flutter build ipa.

Example

curl -fsSL --create-dirs -o ~/.claude/skills/flutter-cross-platform/SKILL.md https://claudeskil.com/skills/flutter-cross-platform/SKILL.md

# then, in your repo:
"Scaffold a login feature using Riverpod with an AsyncNotifier,
 add a widget test, and set up the GitHub Actions release workflow."

Generated provider sketch:

@riverpod
class AuthController extends _$AuthController {
  @override
  FutureOr<User?> build() => null;

  Future<void> signIn(String email, String pw) async {
    state = const AsyncLoading();
    state = await AsyncValue.guard(() => _repo.signIn(email, pw));
  }
}

Tips & gotchas

• Pick one state solution per project. Mixing BLoC and Riverpod in the same feature creates two sources of truth — the skill will ask which to standardize on.
• Riverpod code-gen requires dart run build_runner watch -d; the skill adds this but you must keep it running during development.
• Web builds need flutter build web --wasm or the CanvasKit renderer for pixel-consistent rendering; HTML renderer behaves differently on text and shadows.
• iOS releases still require macOS for flutter build ipa; the CI workflow uses a macos-latest runner for that job and ubuntu-latest for Android.

FAQ

BLoC or Riverpod — which does it recommend? Riverpod for greenfield apps wanting compile-safe DI and less boilerplate; BLoC when your team already knows the event/state pattern or needs explicit, traceable transitions.

Does it handle signing? It scaffolds the config (keystore references, ExportOptions.plist, fastlane match) but you supply secrets via CI environment variables — credentials are never written to the repo.

Can it test navigation and async UI? Yes — it uses pumpAndSettle, bloc_test's expect matchers, and mocktail stubs to cover async states and route transitions.