juice_lifecycle

App lifecycle — foreground / background / resume — as a Juice bloc, behind a swappable provider seam.

What it owns

The app's AppLifecycle phase (resumed / inactive / paused / detached / hidden) plus the previous phase. It does not decide what to do on a transition — consumers react (e.g. re-check permissions on resume, reconnect a socket).

Install

dependencies:
  juice_lifecycle: ^0.1.0

Use

import 'package:juice/juice.dart';
import 'package:juice_lifecycle/juice_lifecycle.dart';

final lifecycle = LifecycleBloc.withConfig(LifecycleConfig());

class PrivacyShield extends StatelessJuiceWidget<LifecycleBloc> {
  PrivacyShield({super.key}) : super(groups: {LifecycleGroups.state});

  @override
  Widget onBuild(BuildContext context, StreamStatus status) {
    // Blur the app in the task switcher when not foreground.
    return bloc.state.isForeground ? const AppBody() : const BlurredScreen();
  }
}

state.resumedFromBackground is handy for "do X when the user comes back" — re-reading permissions, refreshing data, reconnecting.

State

The provider seam (and why it's testable)

LifecycleBloc depends on the LifecycleProvider interface, not on WidgetsBinding. The default WidgetsLifecycleProvider wraps Flutter's AppLifecycleListener; inject a fake in tests:

class FakeLifecycleProvider implements LifecycleProvider {
  final _ctrl = StreamController<AppLifecycle>.broadcast();
  AppLifecycle _current = AppLifecycle.resumed;

  @override Stream<AppLifecycle> get changes => _ctrl.stream;
  @override AppLifecycle get current => _current;
  @override Future<void> dispose() async => _ctrl.close();

  void emit(AppLifecycle p) { _current = p; _ctrl.add(p); }
}

License

MIT License — see LICENSE.