senior-mobile

Senior Mobile Developer

Expert mobile application development across iOS, Android, React Native, and Flutter.

Keywords

mobile, ios, android, react-native, flutter, swift, kotlin, swiftui, jetpack-compose, expo-router, zustand, app-store, performance, offline-first

Quick Start

# Scaffold a React Native project
python scripts/mobile_scaffold.py --platform react-native --name MyApp

# Build for production
python scripts/build.py --platform ios --env production

# Generate App Store metadata
python scripts/store_metadata.py --screenshots ./screenshots

# Profile rendering performance
python scripts/profile.py --platform android --output report.html

Tools

| Script | Purpose | |--------|---------| | scripts/mobile_scaffold.py | Scaffold project for react-native, ios, android, or flutter | | scripts/build.py | Build automation with environment and platform flags | | scripts/store_metadata.py | Generate App Store / Play Store listing metadata | | scripts/profile.py | Profile rendering, memory, and startup performance |

Platform Decision Matrix

| Aspect | Native iOS | Native Android | React Native | Flutter | |--------|-----------|----------------|--------------|---------| | Language | Swift | Kotlin | TypeScript | Dart | | UI Framework | SwiftUI/UIKit | Compose/XML | React | Widgets | | Performance | Best | Best | Good | Very Good | | Code Sharing | None | None | ~80% | ~95% | | Best For | iOS-only, hardware-heavy | Android-only, hardware-heavy | Web team, shared logic | Maximum code sharing |

Workflow 1: Scaffold a React Native App (Expo Router)

1. Generate project -- python scripts/mobile_scaffold.py --platform react-native --name MyApp
2. Verify directory structure matches this layout:

`` src/ ├── app/ # Expo Router file-based routes │ ├── (tabs)/ # Tab navigation group │ ├── auth/ # Auth screens │ └── _layout.tsx # Root layout ├── components/ │ ├── ui/ # Reusable primitives (Button, Input, Card) │ └── features/ # Domain components (ProductCard, UserAvatar) ├── hooks/ # Custom hooks (useAuth, useApi) ├── services/ # API clients and storage ├── stores/ # Zustand state stores └── utils/ # Helpers ``

1. Configure navigation in app/_layout.tsx with Stack and Tabs.
2. Set up state management with Zustand + AsyncStorage persistence.
3. Validate -- Run the app on both iOS simulator and Android emulator. Confirm navigation and state persistence work.

Workflow 2: Build a SwiftUI Feature (iOS)

1. Create the View using NavigationStack, @StateObject for ViewModel binding, and .task for async data loading.
2. Create the ViewModel as @MainActor class with @Published properties. Inject services via protocol for testability.
3. Wire data flow: View observes ViewModel -> ViewModel calls Service -> Service returns data -> ViewModel updates @Published -> View re-renders.
4. Add search/refresh: .searchable(text:) for filtering, .refreshable for pull-to-refresh.
5. Validate -- Run in Xcode previews first, then simulator. Confirm async loading, error states, and empty states all render correctly.

Example: SwiftUI ViewModel Pattern

@MainActor
class ProductListViewModel: ObservableObject {
    @Published private(set) var products: [Product] = []
    @Published private(set) var isLoading = false
    @Published private(set) var error: Error?

    private let service: ProductServiceProtocol

    init(service: ProductServiceProtocol = ProductService()) {
        self.service = service
    }

    func loadProducts() async {
        isLoading = true
        error = nil
        do {
            products = try await service.fetchProducts()
        } catch {
            self.error = error
        }
        isLoading = false
    }
}

Workflow 3: Build a Jetpack Compose Feature (Android)

1. Create the Composable screen with Scaffold, TopAppBar, and state collection via collectAsStateWithLifecycle().
2. Handle UI states with a sealed interface: Loading, Success<T>, Error.
3. Create the ViewModel with @HiltViewModel, MutableStateFlow, and repository injection.
4. Build list UI using LazyColumn with key parameter for stable identity and Arrangement.spacedBy() for spacing.
5. Validate -- Run on emulator. Confirm state transitions (loading -> success, loading -> error -> retry) work correctly.

Example: Compose UiState Pattern

sealed interface UiState<out T> {
    data object Loading : UiState<Nothing>
    data class Success<T>(val data: T) : UiState<T>
    data class Error(val message: String) : UiState<Nothing>
}

@HiltViewModel
class ProductListViewModel @Inject constructor(
    private val repository: ProductRepository
) : ViewModel() {
    private val _uiState = MutableStateFlow<UiState<List<Product>>>(UiState.Loading)
    val uiState: StateFlow<UiState<List<Product>>> = _uiState.asStateFlow()

    fun loadProducts() {
        viewModelScope.launch {
            _uiState.value = UiState.Loading
            repository.getProducts()
                .catch { e -> _uiState.value = UiState.Error(e.message ?: "Unknown error") }
                .collect { products -> _uiState.value = UiState.Success(products) }
        }
    }
}

Workflow 4: Optimize Mobile Performance

1. Profile -- python scripts/profile.py --platform <ios|android> --output report.html
2. Apply React Native optimizations:
3. Use FlatList with keyExtractor, initialNumToRender=10, windowSize=5, removeClippedSubviews=true
4. Memoize components with React.memo and handlers with useCallback
5. Supply getItemLayout for fixed-height rows to skip measurement
6. Apply native iOS optimizations:
7. Implement prefetchItemsAt for image pre-loading in collection views
8. Apply native Android optimizations:
9. Set setHasFixedSize(true) and setItemViewCacheSize(20) on RecyclerViews
10. Validate -- Re-run profiler and confirm frame drops reduced and startup time improved.

Workflow 5: Submit to App Store / Play Store

1. Generate metadata -- python scripts/store_metadata.py --screenshots ./screenshots
2. Build release -- python scripts/build.py --platform ios --env production
3. Review the generated listing (title, description, keywords, screenshots).
4. Upload via Xcode (iOS) or Play Console (Android).
5. Validate -- Monitor review status and address any rejection feedback.

Reference Materials

| Document | Path | |----------|------| | React Native Guide | [references/react_native_guide.md](references/react_native_guide.md) | | iOS Patterns | [references/ios_patterns.md](references/ios_patterns.md) | | Android Patterns | [references/android_patterns.md](references/android_patterns.md) | | App Store Guide | [references/app_store_guide.md](references/app_store_guide.md) | | Full Code Examples | [REFERENCE.md](REFERENCE.md) |

Troubleshooting

| Problem | Cause | Solution | |---------|-------|----------| | App crashes on launch after adding a new dependency | Incompatible native module version or missing pod install / gradle sync | Run npx pod-install (iOS) or cd android && ./gradlew clean (Android). Verify dependency version compatibility in the changelog. | | FlatList renders blank or flickers | Missing keyExtractor, unstable keys, or inline renderItem causing full re-renders | Add a stable keyExtractor, wrap renderItem in useCallback, and supply getItemLayout for fixed-height rows. | | iOS build fails with "signing" error | Provisioning profile mismatch or expired certificate | Open Xcode > Signing & Capabilities, select the correct team and profile. Run security find-identity -v -p codesigning to verify certificates. | | Android build OOM during dexing | Insufficient JVM heap f