---

name: swiftui-patterns description: Master SwiftUI with declarative UI, state management, custom views, animations, and modern iOS development patterns.

SwiftUI Patterns

Build modern iOS apps with SwiftUI's declarative syntax, state management, and reactive patterns.

Core Patterns

Basic View

Copystruct ContentView: View {
    @State private var count = 0

    var body: some View {
        VStack {
            Text("Count: \(count)")
                .font(.largeTitle)

            Button("Increment") {
                count += 1
            }
            .buttonStyle(.borderedProminent)
        }
        .padding()
    }
}

ObservableObject

Copyclass UserViewModel: ObservableObject {
    @Published var users: [User] = []
    @Published var isLoading = false

    func fetchUsers() async {
        isLoading = true
        defer { isLoading = false }

        do {
            users = try await UserService.fetchUsers()
        } catch {
            print("Error: \(error)")
        }
    }
}

struct UserListView: View {
    @StateObject private var viewModel = UserViewModel()

    var body: some View {
        List(viewModel.users) { user in
            Text(user.name)
        }
        .task {
            await viewModel.fetchUsers()
        }
    }
}

Custom ViewModifier

Copystruct CardModifier: ViewModifier {
    func body(content: Content) -> some View {
        content
            .padding()
            .background(Color.white)
            .cornerRadius(10)
            .shadow(radius: 5)
    }
}

extension View {
    func cardStyle() -> some View {
        modifier(CardModifier())
    }
}

Best Practices

1. Use @State for local view state
2. Use @StateObject for view models
3. Use @ObservedObject for passed objects
4. Leverage SwiftUI previews
5. Extract reusable components
6. Use proper property wrappers
7. Implement accessibility

Resources

• https://developer.apple.com/xcode/swiftui/