# 12. App Startup Time & ANR Prevention

meta:
  id: android-production-12
  feature: android-production
  priority: P2
  depends_on: []
  tags: [performance, startup, production]

objective:
- Optimize app startup time and prevent ANRs to ensure smooth user experience

deliverables:
- Startup time measurement and baseline
- Lazy initialization of heavy components
- ANR prevention measures
- App Startup library integration

steps:
1. Measure current startup time:
   - Use Android Studio Profiler
   - Use Macrobenchmark library
   - Measure cold start (first launch)
   - Measure warm start (subsequent launches)
   - Establish baseline metrics
2. Optimize Application.onCreate:
   - Minimize work in KordantApp.onCreate
   - Use App Startup library for initialization ordering
   - Defer non-critical initialization
   - Initialize on background threads where possible
3. Lazy load heavy components:
   - Defer TRPCApiService initialization until needed
   - Lazy load repository dependencies
   - Defer analytics initialization
   - Use Dagger/Hilt lazy injection
4. Optimize theme and layout:
   - Use simple splash theme (windowBackground only)
   - Avoid complex layouts in first screen
   - Preload critical resources
5. Prevent ANRs:
   - Move all IO operations to background threads
   - Use coroutines with Dispatchers.IO
   - Avoid blocking main thread in composables
   - Profile with StrictMode in debug builds
6. Add tests:
   - Macrobenchmark tests for startup time
   - ANR detection in CI
   - Memory usage during startup

tests:
- Performance: Startup time <1.5s on Pixel 6
- ANR: No ANRs during critical flows
- Memory: No memory spikes during startup

acceptance_criteria:
- Cold startup time <1.5 seconds on Pixel 6
- Warm startup time <1 second on Pixel 6
- Splash screen visible for <500ms
- No blocking operations on main thread during startup
- Heavy components loaded lazily
- ANR-free during all critical user flows
- Macrobenchmark tests for startup time
- Startup time tracked in CI
- No StrictMode violations in debug builds

validation:
- Android Profiler → cold start <1.5s
- Macrobenchmark → startup metrics within budget
- StrictMode → no disk/network on main thread
- Physical device test → feels instant
- ANR traces → none from Kordant

notes:
- Android Vitals tracks startup time and ANRs automatically
- ANR threshold is 5 seconds for input, 10 seconds for BroadcastReceiver
- App Startup library helps manage initialization order
- Test on low-end devices (Android 10, 2GB RAM)