ios-swift

## When to use this skill

Use this skill whenever the user wants to:
- Create iOS applications using Swift with SwiftUI or UIKit
- Implement navigation, view controllers, or SwiftUI views and modifiers
- Use async/await, Combine, or URLSession for networking
- Configure Xcode project settings, signing, capabilities, or entitlements
- Persist data with Core Data, SwiftData, or UserDefaults
- Prepare for App Store submission via TestFlight

## How to use this skill

### 1. SwiftUI View

```swift
struct ContentView: View {
    @StateObject private var viewModel = ItemViewModel()

    var body: some View {
        NavigationStack {
            List(viewModel.items) { item in
                NavigationLink(item.name) {
                    DetailView(item: item)
                }
            }
            .navigationTitle("Items")
            .task { await viewModel.loadItems() }
        }
    }
}
```

### 2. ViewModel with async/await

```swift
@MainActor
class ItemViewModel: ObservableObject {
    @Published var items: [Item] = []

    func loadItems() async {
        let (data, _) = try await URLSession.shared.data(from: url)
        items = try JSONDecoder().decode([Item].self, from: data)
    }
}
```

### 3. Navigation (UIKit)

```swift
let detailVC = DetailViewController()
detailVC.item = selectedItem
navigationController?.pushViewController(detailVC, animated: true)
```

### 4. Xcode Configuration

- Set **Signing & Capabilities**: Team, Bundle ID, provisioning profile.
- Add capabilities (Push Notifications, Background Modes) in the Signing tab.
- Archive and upload via **Product -> Archive -> Distribute App**.

## Best Practices

- Perform all UI updates on `@MainActor`; use `[weak self]` in closures to avoid retain cycles.
- Add `NSCameraUsageDescription` and other privacy keys to Info.plist before requesting permissions.
- Test on real devices and via TestFlight before App Store submission.
- Follow Apple Human Interface Guidelines for layout, typography, and navigation patterns.

## Resources

- https://developer.apple.com/documentation/swift
- https://developer.apple.com/documentation/swiftui
- https://developer.apple.com/design/human-interface-guidelines

## Keywords

iOS, Swift, SwiftUI, UIKit, Xcode, async/await, Core Data, TestFlight, App Store