mobile-design

Wrap list items in React.memo, memoize renderItem with useCallback, use a stable keyExtractor with item IDs instead of indexes, and provide getItemLayout for fixed-height items. Consider FlashList for better recycling and memory management on large datasets.

Choose React Native with Expo when you need OTA updates and have a web team familiar with React. Choose Flutter for pixel-perfect identical UI across platforms. Choose native SwiftUI or Kotlin when maximum performance or deep OS integration is required.

iOS requires 44pt by 44pt minimum touch targets while Android requires 48dp by 48dp, with at least 8-12px spacing between adjacent targets. Place primary actions in the thumb zone at the bottom of the screen for one-handed use.

Never store tokens in AsyncStorage or plain key-value storage since they are accessible on rooted devices. Use iOS Keychain, Android EncryptedSharedPreferences, or expo-secure-store, and keep short-lived access tokens in memory with refresh tokens in secure storage.

Immediate launch crashes are almost always native configuration issues in Info.plist or AndroidManifest.xml rather than JavaScript errors. Check native logs with adb logcat on Android or Xcode device logs on iOS, and clean native build caches.

Dark mode saves significant battery only on OLED screens where black pixels are fully powered off. Use true black #000000 for backgrounds to maximize savings, and desaturate colors in dark mode to reduce power draw and eye strain.