swiftui

SwiftUI Best Practices

Overview

Aspect	Recommendation
Version	iOS 17+ / SwiftUI 5
Architecture	MVVM
State	@Observable (iOS 17+)
Navigation	NavigationStack
Concurrency	Swift Concurrency (async/await)

---

Project Structure

App/
├── App.swift                 # @main entry point
├── ContentView.swift
├── Features/
│   ├── Auth/
│   │   ├── Views/
│   │   │   ├── LoginView.swift
│   │   │   └── RegisterView.swift
│   │   ├── ViewModels/
│   │   │   └── AuthViewModel.swift
│   │   └── Models/
│   │       └── User.swift
│   └── Home/
│       └── ...
├── Core/
│   ├── Network/
│   │   └── APIClient.swift
│   ├── Storage/
│   │   └── UserDefaults+Extensions.swift
│   └── Extensions/
├── Shared/
│   ├── Components/
│   │   ├── PrimaryButton.swift
│   │   └── LoadingView.swift
│   └── Modifiers/
└── Resources/
    └── Assets.xcassets

---

View Patterns

Basic View

struct ProfileView: View {
    let user: User
    
    var body: some View {
        VStack(alignment: .leading, spacing: 16) {
            AsyncImage(url: user.avatarURL) { image in
                image
                    .resizable()
                    .aspectRatio(contentMode: .fill)
            } placeholder: {
                ProgressView()
            }
            .frame(width: 100, height: 100)
            .clipShape(Circle())
            
            Text(user.name)
                .font(.title2)
                .fontWeight(.semibold)
            
            Text(user.email)
                .font(.subheadline)
                .foregroundStyle(.secondary)
        }
        .padding()
    }
}

#Preview {
    ProfileView(user: .preview)
}

View with ViewModel

struct HomeView: View {
    @State private var viewModel = HomeViewModel()
    
    var body: some View {
        NavigationStack {
            Group {
                switch viewModel.state {
                case .loading:
                    ProgressView()
                case .loaded(let items):
                    ItemList(items: items)
                case .error(let message):
                    ErrorView(message: message, retry: viewModel.load)
                }
            }
            .navigationTitle("Home")
            .task {
                await viewModel.load()
            }
        }
    }
}