mobile-development

## Overview Mobile apps have unique constraints: unreliable networks, limited battery, strict platform guidelines, and app store review. This skill applies mobile-specific engineering discipline. ## When to Use - Before implementing a new mobile feature - When an app is slow, crashes, or drains battery - Before submitting to the app store ## Process ### Step 1: Design for offline-first Assume the network is unavailable. Design data flows that work offline and sync when connectivity returns. Use optimistic UI updates. ### Step 2: Main thread discipline - No I/O on the main thread - No heavy computation on the main thread - Profile with Instruments (iOS) or Android Profiler for frame drops Target: 60fps during all user interactions. ### Step 3: Memory management - No strong reference cycles (iOS: use weak/unowned) - Instrument for memory leaks before release - Release large resources when the app backgrounds ### Step 4: Battery efficiency - Minimize background work - Batch network requests - Use push over polling - Reduce GPS/sensor usage frequency when precision isn't needed ### Step 5: App size - Analyze app size before each release - Use on-demand resources for large assets - Target: < 30MB download for initial install ### Step 6: Crash rate - Integrate crash reporting from day one (Crashlytics, Sentry) - Fix crashes before shipping new features - Target: < 0.1% crash-free sessions ### Step 7: Accessibility - Dynamic Type support (iOS) / font scaling (Android) - VoiceOver (iOS) / TalkBack (Android) tested - Touch targets ≥ 44pt × 44pt - Color contrast meets WCAG AA ### Step 8: App store compliance - Review App Store / Play Store guidelines for relevant categories before implementing - Test on oldest supported OS version - Implement required privacy labels/permissions honestly ## Verification Requirements - [ ] Offline state handled gracefully - [ ] No I/O or heavy computation on main thread - [ ] Profiled: 60fps during interactions - [ ] Crash reporting integrated - [ ] Accessibility tested with platform screen reader - [ ] App size within budget - [ ] Tested on oldest supported OS version