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migration-navigation-observation.mdskills/swiftui-patterns/references/

SwiftUI Navigation and Observation Migrations

A comprehensive mapping of deprecated, legacy, or fragile SwiftUI and iOS patterns to modern defaults from iOS 15 through iOS 26. Each section shows the old pattern, the modern replacement, and migration notes. Target iOS 26 with Swift 6.3; backward-compatible to iOS 16 unless noted.

NavigationView to NavigationStack

NavigationView was deprecated in iOS 16. Use NavigationStack for push-based navigation with a single column, or NavigationSplitView for multi-column layouts.

Before (Deprecated)

struct ContentView: View {
    var body: some View {
        NavigationView {
            List(items) { item in
                NavigationLink(destination: DetailView(item: item)) {
                    Text(item.title)
                }
            }
            .navigationTitle("Items")
        }
        .navigationViewStyle(.stack)
    }
}

After (Modern)

struct ContentView: View {
    @State private var path: [Item] = []

    var body: some View {
        NavigationStack(path: $path) {
            List(items) { item in
                NavigationLink(value: item) {
                    Text(item.title)
                }
            }
            .navigationTitle("Items")
            .navigationDestination(for: Item.self) { item in
                DetailView(item: item)
            }
        }
    }
}

Migration Notes

NavigationStack gives you programmatic control over the navigation path via a binding. Value-based NavigationLink separates the trigger from the destination, keeping list rows lightweight. The .navigationViewStyle(.stack) modifier is no longer needed.

NavigationView Sidebar to NavigationSplitView

Before (Deprecated)

struct SidebarApp: View {
    var body: some View {
        NavigationView {
            SidebarList()
            DetailPlaceholder()
        }
        .navigationViewStyle(.columns)
    }
}

After (Modern)

struct SidebarApp: View {
    @State private var selectedCategory: Category?
    @State private var selectedItem: Item?

    var body: some View {
        NavigationSplitView {
            List(categories, selection: $selectedCategory) { category in
                Label(category.name, systemImage: category.icon)
            }
            .navigationTitle("Categories")
        } content: {
            if let category = selectedCategory {
                List(category.items, selection: $selectedItem) { item in
                    Text(item.title)
                }
            } else {
                ContentUnavailableView("Select a Category",
                                       systemImage: "sidebar.left")
            }
        } detail: {
            if let item = selectedItem {
                DetailView(item: item)
            } else {
                ContentUnavailableView("Select an Item",
                                       systemImage: "doc.text")
            }
        }
    }
}

Migration Notes

NavigationSplitView explicitly models two-column and three-column layouts. Column visibility is controlled via NavigationSplitViewVisibility and columnVisibility bindings. On compact size classes the split view collapses into a NavigationStack automatically.

ObservableObject / @Published / @StateObject to @Observable / @State

The Observation framework (iOS 17+) replaces Combine-based observation. Classes annotated with @Observable track property access automatically -- no @Published wrappers needed.

Before (Superseded)

class UserSettings: ObservableObject {
    @Published var username: String = ""
    @Published var notificationsEnabled: Bool = true
    @Published var theme: Theme = .system

    func resetToDefaults() {
        username = ""
        notificationsEnabled = true
        theme = .system
    }
}

struct SettingsView: View {
    @StateObject private var settings = UserSettings()

    var body: some View {
        Form {
            TextField("Username", text: $settings.username)
            Toggle("Notifications", isOn: $settings.notificationsEnabled)
            Picker("Theme", selection: $settings.theme) {
                ForEach(Theme.allCases) { theme in
                    Text(theme.rawValue).tag(theme)
                }
            }
        }
    }
}

After (Modern)

@Observable
class UserSettings {
    var username: String = ""
    var notificationsEnabled: Bool = true
    var theme: Theme = .system

    func resetToDefaults() {
        username = ""
        notificationsEnabled = true
        theme = .system
    }
}

struct SettingsView: View {
    @State private var settings = UserSettings()

    var body: some View {
        Form {
            TextField("Username", text: $settings.username)
            Toggle("Notifications", isOn: $settings.notificationsEnabled)
            Picker("Theme", selection: $settings.theme) {
                ForEach(Theme.allCases) { theme in
                    Text(theme.rawValue).tag(theme)
                }
            }
        }
    }
}

Migration Notes

  • Replace ObservableObject conformance with the @Observable macro.
  • Remove all @Published property wrappers -- observation is automatic.
  • Replace @StateObject with @State for owned instances.
  • Computed properties that depend on stored properties are tracked automatically.
  • The view only re-evaluates when properties it actually reads change, so fine-grained observation is free.
  • Requires iOS 17+ minimum deployment target. ObservableObject is not formally deprecated (no compiler warning) -- it is superseded. Do not rewrite working ObservableObject code if the project targets iOS 16 or earlier.

@ObservedObject to let / @Bindable

Before (Superseded)

struct ProfileEditor: View {
    @ObservedObject var profile: ProfileModel

    var body: some View {
        TextField("Name", text: $profile.name)
        Toggle("Public", isOn: $profile.isPublic)
    }
}

After (Modern)

When you only need to read properties, use a plain let:

struct ProfileDisplay: View {
    let profile: ProfileModel  // @Observable class

    var body: some View {
        Text(profile.name)
        Text(profile.isPublic ? "Public" : "Private")
    }
}

When you need to create bindings, use @Bindable:

struct ProfileEditor: View {
    @Bindable var profile: ProfileModel

    var body: some View {
        TextField("Name", text: $profile.name)
        Toggle("Public", isOn: $profile.isPublic)
    }
}

Migration Notes

With @Observable, you no longer need @ObservedObject to subscribe to changes. A plain let constant already triggers view updates when read properties change. Use @Bindable only when you need two-way bindings via $ syntax.

@EnvironmentObject to @Environment

Before (Superseded)

// Injection
ContentView()
    .environmentObject(authManager)

// Usage
struct ContentView: View {
    @EnvironmentObject var auth: AuthManager

    var body: some View {
        if auth.isLoggedIn {
            HomeView()
        } else {
            LoginView()
        }
    }
}

After (Modern)

// Injection
ContentView()
    .environment(authManager)

// Usage
struct ContentView: View {
    @Environment(AuthManager.self) private var auth

    var body: some View {
        if auth.isLoggedIn {
            HomeView()
        } else {
            LoginView()
        }
    }
}

Migration Notes

With @Observable, use .environment(_:) (the type-keyed overload) instead of .environmentObject(_:). Read with @Environment(Type.self). If you need bindings from an environment-injected object, pull it into a local @Bindable:

struct ContentView: View {
    @Environment(AuthManager.self) private var auth

    var body: some View {
        @Bindable var auth = auth
        Toggle("Remember Me", isOn: $auth.rememberMe)
    }
}

skills

swiftui-patterns

references

architecture-patterns.md

design-polish.md

migration-data-and-modern-apis.md

migration-navigation-observation.md

migration-view-lifecycle-layout.md

platform-and-sharing.md

preview-isolation.md

project-structure.md

view-refactoring.md

SKILL.md

.mcp.json

README.md

tile.json