Swiftui UI Patterns

SwiftUI UI Patterns

Quick Start

Choose a track based on your goal:

Existing project

• Identify the feature or screen and the primary interaction model (list, detail, editor, settings, tabbed).
• Find a nearby example in the repo with rg "TabView\(" or similar, then read the closest SwiftUI view.
• Apply local conventions: prefer SwiftUI-native state, keep state local when possible, and use environment injection for shared dependencies.
• Build the view with small, focused subviews and SwiftUI-native data flow.

New project scaffolding

• Start with TabView + NavigationStack + sheets wiring.
• Add a minimal AppTab and RouterPath based on the provided skeletons.
• Expand the route and sheet enums as new screens are added.

General Rules

• Use modern SwiftUI state (@State, @Binding, @Observable, @Environment) and avoid unnecessary view models.
• Prefer composition; keep views small and focused.
• Use async/await with .task and explicit loading/error states.
• Maintain existing legacy patterns only when editing legacy files.
• Follow the project's formatter and style guide.

Workflow for a New SwiftUI View

1. Define the view's state and its ownership location.
2. Identify dependencies to inject via @Environment.
3. Sketch the view hierarchy and extract repeated parts into subviews.
4. Implement async loading with .task and explicit state enum if needed.
5. Add accessibility labels or identifiers when the UI is interactive.
6. Validate with a build and update usage callsites if needed.

App Architecture Patterns

Tab-based Navigation

enum AppTab: String, CaseIterable {
    case home, search, profile
    
    var title: String {
        rawValue.capitalized
    }
    
    var icon: String {
        switch self {
        case .home: return "house"
        case .search: return "magnifyingglass"
        case .profile: return "person"
        }
    }
}

struct ContentView: View {
    @State private var selectedTab: AppTab = .home
    
    var body: some View {
        TabView(selection: $selectedTab) {
            ForEach(AppTab.allCases, id: \.self) { tab in
                NavigationStack {
                    tabContent(for: tab)
                }
                .tabItem {
                    Label(tab.title, systemImage: tab.icon)
                }
                .tag(tab)
            }
        }
    }
    
    @ViewBuilder
    private func tabContent(for tab: AppTab) -> some View {
        switch tab {
        case .home: HomeView()
        case .search: SearchView()
        case .profile: ProfileView()
        }
    }
}

Router Pattern

enum Route: Hashable {
    case detail(id: String)
    case settings
    case edit(item: Item)
}

@Observable
class Router {
    var path = NavigationPath()
    
    func navigate(to route: Route) {
        path.append(route)
    }
    
    func pop() {
        path.removeLast()
    }
    
    func popToRoot() {
        path.removeLast(path.count)
    }
}

struct RootView: View {
    @State private var router = Router()
    
    var body: some View {
        NavigationStack(path: $router.path) {
            HomeView()
                .navigationDestination(for: Route.self) { route in
                    switch route {
                    case .detail(let id):
                        DetailView(id: id)
                    case .settings:
                        SettingsView()
                    case .edit(let item):
                        EditView(item: item)
                    }
                }
        }
        .environment(router)
    }
}

Sheet Management

enum Sheet: Identifiable {
    case newItem
    case editItem(Item)
    case settings
    
    var id: String {
        switch self {
        case .newItem: return "newItem"
        case .editItem(let item): return "edit-\(item.id)"
        case .settings: return "settings"
        }
    }
}

struct ParentView: View {
    @State private var activeSheet: Sheet?
    
    var body: some View {
        Button("New Item") {
            activeSheet = .newItem
        }
        .sheet(item: $activeSheet) { sheet in
            switch sheet {
            case .newItem:
                NewItemSheet()
            case .editItem(let item):
                EditItemSheet(item: item)
            case .settings:
                SettingsSheet()
            }
        }
    }
}

Component Patterns

List with Loading States

enum LoadingState<T> {
    case idle
    case loading
    case loaded(T)
    case error(Error)
}

struct ItemListView: View {
    @State private var state: LoadingState<[Item]> = .idle
    
    var body: some View {
        Group {
            switch state {
            case .idle:
                Color.clear
            case .loading:
                ProgressView()
            case .loaded(let items):
                List(items) { item in
                    ItemRow(item: item)
                }
            case .error(let error):
                ErrorView(error: error, retry: loadItems)
            }
        }
        .task { await loadItems() }
    }
    
    private func loadItems() async {
        state = .loading
        do {
            let items = try await fetchItems()
            state = .loaded(items)
        } catch {
            state = .error(error)
        }
    }
}

Search with Debouncing

struct SearchView: View {
    @State private var query = ""
    @State private var results: [Result] = []
    @State private var searchTask: Task<Void, Never>?
    
    var body: some View {
        List(results) { result in
            ResultRow(result: result)
        }
        .searchable(text: $query)
        .onChange(of: query) { _, newValue in
            searchTask?.cancel()
            searchTask = Task {
                try? await Task.sleep(for: .milliseconds(300))
                guard !Task.isCancelled else { return }
                results = await search(newValue)
            }
        }
    }
}

Pull to Refresh

struct RefreshableListView: View {
    @State private var items: [Item] = []
    
    var body: some View {
        List(items) { item in
            ItemRow(item: item)
        }
        .refreshable {
            items = await fetchItems()
        }
        .task {
            items = await fetchItems()
        }
    }
}

Swipe Actions

struct SwipeableRow: View {
    let item: Item
    let onDelete: () -> Void
    let onArchive: () -> Void
    
    var body: some View {
        Text(item.title)
            .swipeActions(edge: .trailing) {
                Button(role: .destructive, action: onDelete) {
                    Label("Delete", systemImage: "trash")
                }
            }
            .swipeActions(edge: .leading) {
                Button(action: onArchive) {
                    Label("Archive", systemImage: "archivebox")
                }
                .tint(.blue)
            }
    }
}

Context Menu

struct ContextMenuRow: View {
    let item: Item
    
    var body: some View {
        ItemRow(item: item)
            .contextMenu {
                Button {
                    // Copy action
                } label: {
                    Label("Copy", systemImage: "doc.on.doc")
                }
                
                Button {
                    // Share action
                } label: {
                    Label("Share", systemImage: "square.and.arrow.up")
                }
                
                Divider()
                
                Button(role: .destructive) {
                    // Delete action
                } label: {
                    Label("Delete", systemImage: "trash")
                }
            }
    }
}

Form Patterns

Validated Form

struct SignUpForm: View {
    @State private var email = ""
    @State private var password = ""
    @State private var confirmPassword = ""
    
    private var isEmailValid: Bool {
        email.contains("@") && email.contains(".")
    }
    
    private var isPasswordValid: Bool {
        password.count >= 8
    }
    
    private var passwordsMatch: Bool {
        password == confirmPassword
    }
    
    private var isFormValid: Bool {
        isEmailValid && isPasswordValid && passwordsMatch
    }
    
    var body: some View {
        Form {
            Section {
                TextField("Email", text: $email)
                    .textContentType(.emailAddress)
                    .keyboardType(.emailAddress)
                    .autocapitalization(.none)
                
                if !email.isEmpty && !isEmailValid {
                    Text("Please enter a valid email")
                        .font(.caption)
                        .foregroundStyle(.red)
                }
            }
            
            Section {
                SecureField("Password", text: $password)
                SecureField("Confirm Password", text: $confirmPassword)
                
                if !password.isEmpty && !isPasswordValid {
                    Text("Password must be at least 8 characters")
                        .font(.caption)
                        .foregroundStyle(.red)
                }
                
                if !confirmPassword.isEmpty && !passwordsMatch {
                    Text("Passwords don't match")
                        .font(.caption)
                        .foregroundStyle(.red)
                }
            }
            
            Section {
                Button("Sign Up") {
                    // Submit
                }
                .disabled(!isFormValid)
            }
        }
    }
}

Settings Form

struct SettingsView: View {
    @AppStorage("notifications") private var notificationsEnabled = true
    @AppStorage("darkMode") private var darkModeEnabled = false
    @AppStorage("fontSize") private var fontSize = 14.0
    
    var body: some View {
        Form {
            Section("Preferences") {
                Toggle("Notifications", isOn: $notificationsEnabled)
                Toggle("Dark Mode", isOn: $darkModeEnabled)
            }
            
            Section("Display") {
                Slider(value: $fontSize, in: 12...24, step: 1) {
                    Text("Font Size")
                }
                Text("Preview: \(Int(fontSize))pt")
                    .font(.system(size: fontSize))
            }
            
            Section {
                Button("Reset to Defaults", role: .destructive) {
                    notificationsEnabled = true
                    darkModeEnabled = false
                    fontSize = 14.0
                }
            }
        }
        .navigationTitle("Settings")
    }
}

Accessibility

Basic Accessibility

struct AccessibleButton: View {
    let action: () -> Void
    
    var body: some View {
        Button(action: action) {
            Image(systemName: "heart.fill")
        }
        .accessibilityLabel("Add to favorites")
        .accessibilityHint("Double-tap to add this item to your favorites")
    }
}

Grouped Accessibility

struct StatCard: View {
    let title: String
    let value: Int
    
    var body: some View {
        VStack {
            Text(title)
                .font(.caption)
            Text("\(value)")
                .font(.title)
        }
        .accessibilityElement(children: .combine)
        .accessibilityLabel("\(title): \(value)")
    }
}

Notes

• Always test on multiple device sizes
• Use SF Symbols for icons when possible
• Prefer system colors for automatic dark mode support
• Keep animations subtle and respect reduced motion settings