swiftui-patterns

name	swiftui-patterns
description	SwiftUI Patterns: Declarative UI, State management, Navigation, Composability, Animations.
triggers	{"extensions":[".swift"],"directories":["ios/","macos/","swift/","apple/"],"keywords":["swiftui","swift","xcode","ios","macos","watchos","apple","@State","@Binding","@ObservedObject","@Environment"]}
auto_load_when	Building Apple native apps with SwiftUI
agent	swift-developer
tools	["Read","Write","Bash"]

SwiftUI Architecture Patterns

Focus: Declarative UI, state management, modern Swift

1. SwiftUI Core Concepts

State Management:
├── @State - Local view state
│   └── struct ContentView: View {
│       @State private var isPresented = false
│   }
│
├── @Binding - Two-way binding
│   └── Child receives reference, can modify parent
│
├── @ObservedObject - External reference type
│   └── class MyViewModel: ObservableObject
│   └── @Published properties trigger view update
│
├── @Environment - Injected dependencies
│   └── @Environment(\.colorScheme) var colorScheme
│   └── @Environment(\.dismiss) var dismiss
│
└── @StateObject - View-owned lifecycle
    └── @StateObject var viewModel = MyViewModel()

---

2. Modern Swift (5.9+)

Concurrency:
├── async/await
│   └── func fetchData() async throws -> Data
│
├── Task and TaskGroup
│   └── await withTaskGroup(of: Void.self) { group in
│       group.addTask { await self.fetchA() }
│       group.addTask { await self.fetchB() }
│   }
│
├── Actor for thread safety
│   └── actor DataStore { ... }
│
└── @MainActor for UI updates
    └── @MainActor func updateUI() // runs on main thread

---

3. Navigation Patterns

Navigation Types:
├── NavigationStack (iOS 16+)
│   └── NavigationLink(value:) → NavigationDestination
│   └── Type-safe navigation with path
│
├── NavigationPath
│   └── let path = NavigationPath()
│   └── path.append(Destination.detail)
│
├── Sheet and FullScreenCover
│   └── .sheet(isPresented:) { SheetContent() }
│
└── TabView
    └── TabView { ... }
    └── .tabViewStyle(.page) for carousel

---

4. Data Flow

Data Flow Patterns:
├── @FetchRequest for Core Data
│   └── @FetchRequest(sortDescriptors: ...) var items: FetchedResults<Item>
│
├── @Query for SwiftData (iOS 17+)
│   └── @Query var items: [Item]
│
└── Networking with async/await
    └── struct API {
        static func fetch() async throws -> [Model]
    }
    └── URLSession.shared.data(from: url)

---

Key Patterns

1. Single source of truth - ObservableObject or SwiftData
2. Immutable views - @State for local, @Binding for passed
3. Lazy loading - LazyVStack, LazyVGrid for performance
4. Type-safe navigation - NavigationStack over NavigationView
5. Modern concurrency - async/await over completion handlers

---

Anti-Patterns

❌ Using @StateObject in structs — only in views
✅ Class conforms to ObservableObject, use @ObservedObject or @StateObject in view

❌ Mixing UIKit and SwiftUI unnecessarily
✅ Use UIViewRepresentable only when needed

❌ Not handling loading/error states
✅ Use @State var isLoading: Bool = false, show Alert on error

❌ Hardcoded frames — breaks accessibility
✅ Use .frame(maxWidth: .infinity) not fixed widths

❌ Not supporting Dynamic Type
✅ Use .font(.body) not .font(.system(size: 17))

---

Quick Reference

Pattern	SwiftUI	UIKit equivalent
List	List {}	UITableView
ScrollView	ScrollView {}	UIScrollView
Button	Button("Title") {}	UIButton
TextField	TextField("Label", text: $var)	UITextField
Image	Image("name")	UIImageView
Navigation	NavigationStack {}	UINavigationController
Tab	TabView {}	UITabBarController

🌍 Universal Language Support

• Turkish Native: This skill natively supports Turkish. If the user prompt is in Turkish, all analysis, formatting, and output MUST be entirely in Turkish. You do not need explicit "write in Turkish" instructions.