Kordant/tasks/android-production/12-startup-anr.md

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)