xcode-swift-dev

name	xcode-swift-dev
description	Expert in Swift/SwiftUI development for macOS menu bar apps, iOS apps, widgets, and Xcode project configuration. Use for Swift architecture, SwiftUI patterns, App Intents, WidgetKit, and native Apple platform development.

Xcode Swift Developer

Expert guidance for native Apple platform development with Swift and SwiftUI.

When to Use

• Building macOS menu bar apps
• Creating iOS/macOS widgets (WidgetKit)
• Implementing App Intents and Shortcuts
• SwiftUI component architecture
• Xcode project configuration
• Swift Package Manager setup
• Code signing and entitlements
• App Store / TestFlight preparation

Core Principles

SwiftUI Architecture

• Use MVVM with @Observable (iOS 17+) or ObservableObject
• Prefer composition over inheritance
• Keep views small and focused
• Extract reusable components to separate files

Project Structure (macOS Menu Bar App)

AppName/
├── App/
│   └── AppNameApp.swift          # @main entry point
├── Models/
│   ├── ServiceType.swift         # Enums and data models
│   └── UsageMetrics.swift        # Core data structures
├── Services/
│   ├── ServiceManager.swift      # Business logic
│   ├── KeychainManager.swift     # Secure storage
│   └── APIClient.swift           # Network layer
├── Views/
│   ├── MenuBarView.swift         # Main menu bar content
│   ├── SettingsView.swift        # Preferences window
│   └── Components/               # Reusable UI components
└── Info.plist

AppNameWidget/
├── AppNameWidgetBundle.swift     # Widget bundle entry
├── UsageWidget.swift             # Widget implementation
├── Assets.xcassets/
└── Info.plist

Menu Bar App Pattern

@main
struct AppNameApp: App {
    @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    var body: some Scene {
        MenuBarExtra("App Name", systemImage: "chart.bar") {
            MenuBarView()
        }
        .menuBarExtraStyle(.window)

        Settings {
            SettingsView()
        }
    }
}

Widget Development

• Use TimelineProvider for data updates
• Keep widget views lightweight
• Support multiple widget families (small, medium, large)
• Use @Environment(\.widgetFamily) for adaptive layouts
• Share data via App Groups

Keychain Best Practices

• Use kSecClassGenericPassword for API keys
• Set kSecAttrAccessible appropriately
• Group related items with kSecAttrService
• Handle errors gracefully (item not found, access denied)

Swift Concurrency

• Use async/await for asynchronous operations
• Mark main-thread-bound code with @MainActor
• Use Task for launching async work from sync contexts
• Prefer AsyncStream for continuous data

Code Signing & Entitlements

Common entitlements for menu bar apps:

• com.apple.security.app-sandbox
• com.apple.security.network.client
• com.apple.security.keychain-access-groups
• com.apple.security.application-groups (for widget data sharing)

SwiftLint Configuration

disabled_rules:
  - line_length
  - trailing_whitespace

opt_in_rules:
  - empty_count
  - closure_spacing
  - force_unwrapping

excluded:
  - .build
  - .swiftpm

Common Patterns

API Client

actor APIClient {
    private let session = URLSession.shared
    private let baseURL: URL

    func fetch<T: Decodable>(_ endpoint: String) async throws -> T {
        let url = baseURL.appendingPathComponent(endpoint)
        let (data, response) = try await session.data(from: url)
        guard let httpResponse = response as? HTTPURLResponse,
              (200...299).contains(httpResponse.statusCode) else {
            throw APIError.invalidResponse
        }
        return try JSONDecoder().decode(T.self, from: data)
    }
}

Shared Data Store (App Groups)

final class SharedDataStore {
    static let shared = SharedDataStore()

    private let defaults: UserDefaults

    init() {
        defaults = UserDefaults(suiteName: "group.com.company.appname")!
    }

    var usageData: UsageData? {
        get {
            guard let data = defaults.data(forKey: "usageData") else { return nil }
            return try? JSONDecoder().decode(UsageData.self, from: data)
        }
        set {
            let data = try? JSONEncoder().encode(newValue)
            defaults.set(data, forKey: "usageData")
        }
    }
}

File Naming Conventions

• Views: *View.swift (e.g., SettingsView.swift)
• Models: Descriptive nouns (e.g., UsageMetrics.swift)
• Services: *Manager.swift or *Service.swift
• Extensions: Type+Extension.swift
• Protocols: *Protocol.swift or *able.swift

Testing

• Use XCTest for unit tests
• Test business logic in Services
• Use @testable import for internal access
• Mock network with URLProtocol
• Snapshot test SwiftUI views with swift-snapshot-testing

Build Configuration

Debug vs Release

• Use #if DEBUG for debug-only code
• Configure schemes for different environments
• Use .xcconfig files for build settings
• Keep secrets out of source (use Keychain or secure config)