Sarcopenia Diagnostic System

A landscape-locked Android tablet system built from scratch to digitize the SPPB (Short Physical Performance Battery) clinical protocol. Developed as a Melos-managed Flutter monorepo with a shell orchestrator app and five standalone sub-apps — Balance Plate, Gait Speed, Chair Stand, Hand Grip, and Anthropometry — each runnable independently or launched on-demand by the shell. The same codebase also compiles Flutter Web builds for browser-based access.

Enabling the shell app to launch sub-apps and receive their results while each sub-app also remains fully runnable in isolation. I solved this by defining a clean session-contract interface in the shared core package — the shell passes patient context via GoRouter deep links, and each sub-app reads from a scoped BLoC state that resolves whether it was launched standalone or orchestrated. Separately, connecting five BLE/USB sensors without thread blockage required a centralized reactive stream manager in the shared layer.

// Melos monorepo check and GoRouter session orchestration
class SarcopeniaSessionNavigator implements ModuleNavigator {
  final GoRouter _router;
  final SarcopeniaSessionState _sessionState;

  @override
  void continueToModule(SarcopeniaModule nextModule) {
    _sessionState.markCompleted(_sessionState.currentModule);
    _sessionState.setCurrentModule(nextModule);
    
    final String targetPath = switch(nextModule) {
      SarcopeniaModule.balancePlate => AppRoutePaths.balancePlate,
      SarcopeniaModule.gaitSpeed => AppRoutePaths.gaitSpeed,
      SarcopeniaModule.chairStand => AppRoutePaths.chairStand,
      SarcopeniaModule.handGrip => AppRoutePaths.handGrip,
      SarcopeniaModule.anthropometry => AppRoutePaths.anthropometry,
    };
    
    _router.pushReplacement(targetPath);
  }
}