Agent Skills: iOS Fundamentals Skill

iOS Fundamentals Skill

Build rock-solid foundations for iOS development

Learning Objectives

By completing this skill, you will:

• Understand iOS app lifecycle and state management
• Master architectural patterns (MVC, MVVM, Clean)
• Implement memory-safe code with ARC
• Use modern Swift concurrency (async/await, actors)
• Apply dependency injection patterns

Prerequisites

| Requirement | Level | |-------------|-------| | Swift basics | Intermediate | | Xcode familiarity | Basic | | OOP concepts | Solid |

Curriculum

Module 1: App Lifecycle (4 hours)

Topics:

• UIApplicationDelegate methods
• SceneDelegate for multi-window (iOS 13+)
• SwiftUI App lifecycle (@main, ScenePhase)
• State transitions: Active → Inactive → Background → Suspended

Code Example:

.onChange(of: scenePhase) { oldPhase, newPhase in
    switch newPhase {
    case .active: resumeActivities()
    case .inactive: pauseActivities()
    case .background: saveState()
    @unknown default: break
    }
}

Module 2: Architecture Patterns (6 hours)

Pattern Comparison:

| Pattern | Complexity | Testability | Team Size | |---------|------------|-------------|-----------| | MVC | Low | Poor | 1-2 | | MVVM | Medium | Good | 2-5 | | Clean/VIP | High | Excellent | 5+ |

Module 3: Memory Management (4 hours)

Topics:

• ARC fundamentals
• Weak/unowned references
• Retain cycle prevention
• Instruments profiling

Module 4: Swift Concurrency (6 hours)

Topics:

• async/await basics
• Task and TaskGroup
• Actors and Sendable
• MainActor for UI

Module 5: Dependency Injection (3 hours)

Topics:

• Constructor injection
• Protocol-oriented design
• Testing with mocks

Assessment Criteria

| Criteria | Weight | |----------|--------| | Architecture understanding | 30% | | Memory management | 25% | | Concurrency implementation | 25% | | Code quality & patterns | 20% |

Skill Validation

1. State Machine App: Proper lifecycle handling
2. MVVM Refactor: Convert MVC to MVVM
3. Concurrent Downloader: async/await image loader