Programming Ios

Mental model

A modern iOS app is SwiftUI views over @Observable models, with SwiftData (or a small repository layer) for persistence and App Intents for system-level integration. UIKit is the escape hatch for what SwiftUI can't yet express. Architectural mistakes show up as massive view bodies, scattered singletons, and tight coupling to UIApplication — design for testability by isolating side effects behind protocols.

Architecture

• Feature-first organization: each feature owns its views, models, intents, and tests in one folder
• Domain logic lives in framework-free Swift modules (a separate SPM target) — the UI imports the domain, not the other way around
• Side effects (network, persistence, system services) hide behind protocols injected via @Environment or initializer parameters
• Avoid singletons except for genuinely process-wide resources (logger, telemetry); inject everything else
• Keep App and Scene definitions thin — they wire dependencies and nothing more

SwiftUI patterns

• @Observable model classes for view state; @Bindable to create bindings to their properties
• NavigationStack with typed NavigationLink(value:) for type-safe routing; NavigationPath for heterogeneous stacks
• NavigationSplitView for iPad/macOS layouts — collapses to stack on iPhone automatically
• .task modifier for async work tied to view lifetime — cancels on disappear
• .environment(...) to inject services down the tree; custom EnvironmentKey for app-specific dependencies
• View bodies should read like a layout description — push computation into the model

Data and persistence

• SwiftData with @Model for new projects — schema is derived from the type, lightweight migrations are automatic
• @Query in views for filtered, sorted, animated fetches
• ModelContainer configured at the app entry point; injected via .modelContainer(...)
• CloudKit sync via SwiftData when cross-device persistence is needed
• #Predicate macro for type-safe queries; VersionedSchema + SchemaMigrationPlan for non-trivial migrations
• For non-SwiftData persistence, hide Core Data / files / keychain behind a repository protocol

System integration

• App Intents make actions discoverable by Shortcuts, Siri, Spotlight, and Apple Intelligence
• AppEntity for domain objects the system can reason about; AppShortcutsProvider for surfaced shortcuts
• Widgets via WidgetKit with TimelineProvider; Live Activities via ActivityKit for lock-screen and Dynamic Island
• StoreKit 2 (Product.products(for:), Transaction.currentEntitlements) — no delegate callbacks, no receipt parsing
• PrivacyInfo.xcprivacy declares all required-reason API usage — ship with it from day one

UIKit interop

• Wrap UIKit views with UIViewRepresentable / UIViewControllerRepresentable only when SwiftUI lacks an equivalent
• Keep the bridge thin: a single representable per feature, not scattered across views
• For UIKit-first apps, embed SwiftUI screens via UIHostingController — incremental migration works well

Concurrency

• Adopt Swift 6 strict concurrency — main-thread mistakes become compile errors
• @MainActor on view models and anything touching UIKit/SwiftUI
• Network and persistence on background actors or detached tasks; results cross back via await
• Cancel structured tasks (.task) automatically; for unstructured work, hold Task handles and cancel explicitly

Testing

• Swift Testing (@Test, #expect, @Suite) for unit and integration tests
• Test the domain target without the app — fast, deterministic, no simulator
• #Preview doubles as a visual test for layout across states
• XCUITest for end-to-end flows; keep them short and focused on critical user paths
• Mock system services by injecting the protocol you defined, not by stubbing Apple's classes

Distribution

• TestFlight for internal and external betas; phased rollouts on App Store releases
• Stay current with the Privacy Manifest required-reason API list — Apple expands it regularly
• Symbolicate crash reports via dSYMs uploaded with each build

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Muvon
• Source: Muvon/octomind-tap
• License: Apache-2.0
• Homepage: https://octomind.run/tap/

Install and usage instructions live in the source repository linked above.