iOS Development Best Practices

Overview

This context provides best practices and guidelines for developing iOS applications using Swift and SwiftUI. Follow these principles to create robust, maintainable, and user-friendly iOS apps.

Architecture Patterns

MVVM (Model-View-ViewModel)

• Separate business logic from UI
• Use @ObservedObject and @StateObject for view models
• Keep views simple and focused on presentation

Clean Architecture

• Domain layer independent of frameworks
• Use protocols for dependency injection
• Separate concerns into distinct layers

SwiftUI Best Practices

State Management

@State private var isLoading = false
@StateObject private var viewModel = ViewModel()
@EnvironmentObject var appState: AppState

View Composition

• Break down complex views into smaller components
• Use ViewBuilders for conditional content
• Leverage view modifiers for reusable styling

Performance

• Use LazyVStack and LazyHStack for large lists
• Implement .onAppear and .onDisappear for lifecycle management
• Cache expensive computations

Swift Language Features

Concurrency

Task {
    await fetchData()
}

actor DataManager {
    private var cache: [String: Data] = [:]
}

Error Handling

• Use Result type for explicit success/failure
• Implement proper do-catch blocks
• Create custom error types for domain-specific errors

Testing Strategies

Unit Testing

• Test view models independently
• Mock dependencies using protocols
• Aim for >80% code coverage

UI Testing

• Test critical user flows
• Use accessibility identifiers
• Implement page object pattern

Snapshot Testing

• Verify UI consistency across devices
• Test dark mode appearance
• Check different dynamic type sizes

App Store Guidelines

Submission Checklist

• Privacy policy URL
• App screenshots for all device sizes
• Localized metadata
• TestFlight beta testing

Common Rejection Reasons

• Incomplete functionality
• Broken links or features
• Inappropriate content
• Privacy violations

Performance Optimization

Memory Management

• Use weak/unowned references appropriately
• Implement proper cleanup in deinit
• Monitor memory usage with Instruments

Battery Life

• Minimize background tasks
• Use efficient networking strategies
• Implement proper location services handling

Accessibility

VoiceOver Support

• Add meaningful accessibility labels
• Implement accessibility hints
• Group related elements

Dynamic Type

• Support all text sizes
• Use scalable fonts
• Test with accessibility inspector

Security

Data Protection

• Use Keychain for sensitive data
• Implement certificate pinning
• Enable App Transport Security

Authentication

• Implement biometric authentication
• Use OAuth 2.0 for third-party services
• Store tokens securely

Debugging Tools

Xcode Instruments

• Time Profiler for performance
• Allocations for memory leaks
• Network instrument for API calls

LLDB Commands

po variable
expr variable = newValue
bt all

Resources

• Apple Developer Documentation
• Human Interface Guidelines
• WWDC Videos
• Swift Evolution