We are a small team of two software engineers who love creating native apps for Apple platforms, Natalia Panferova and Matthaus Woolard. Beyond building great apps, we’re dedicated to sharing our expertise and contributing to the tech community.
Book update expands SwiftUI data-flow and performance guidance: stable custom bindings, how equality drives property tracking in observable models, environment-based configuration/actions without extra updates, Xcode 27’s @State macro impacts, and why not to use full Hashable as list identity.
SwiftUI’s @Observable tracks per-property reads, but if a stored type isn’t Equatable, every assignment triggers view invalidation. Make custom value types (and array elements) Equatable so setters can skip notifications when values are equal. In-place mutations still notify; equality on large collections has a cost.
Xcode 27 warns when a SwiftUI @Entry environment default allocates a class per access. Each fallback returns a new reference, so SwiftUI sees a changed environment and re-renders dependents. Fix by referencing a shared stored instance or making it optional and injecting. Avoid unstable defaults like Date() and UUID().
Explains that Binding(get:set:) recreates closures on each body run, causing allocations and unnecessary row updates when unrelated state changes. Prefer a labeled subscript on an @Observable model and bind via $model[...] for a stable dependency. Use _printChanges() to debug.
iOS 27 upgrades SwiftUI AsyncImage: new URLRequest initializers let you set headers (auth), cache policy, and timeouts; a phase-based form + Transaction handles loading/success/failure; asyncImageURLSession(_:) injects a shared URLSession. When request is nil, the placeholder remains.
iOS 27 adds container‑agnostic reordering and drag to SwiftUI. Use reorderable() + reorderContainer(for:) and apply ReorderDifference to your data. Across sections, tag items with collectionID and use reorderContainer(for:in:). New drag containers support multi‑item drags with Transferable values.
iOS 27 updates SwiftUI NavigationTransition: adds CrossFadeNavigationTransition (.crossFade) to fade sheets/full‑screen covers, and AnyNavigationTransition to pick a transition at runtime (e.g., deep link vs tap). Examples show .crossFade and type erasure; custom transitions still unsupported.
iOS 27 extends swipeActions beyond List. Add swipeActionsContainer() to ScrollView and swipeActions(...) to each row in LazyVStack/Grid/custom Layouts. The container keeps rows exclusive and dismisses on scroll/tap. Gate with #available; onPresentationChanged tracks state.
Xcode 27 makes @State a macro with lazy init. @Observable models in @State now initialize once when state storage is created, avoiding repeated work on view re-creations. Still avoid assigning in init(); use task(id:) if the model depends on parent data.
Style Measurement units separately in SwiftUI by adding a Text init that formats via AttributedString and uses transformingAttributes(.measurement, .font) to set Font for .unit only. Value can still use outer modifiers; use .measurement(width: .narrow) to remove the space.
Deep dive into SwiftUI animation timing: use Animation via animation(_:value:) or withAnimation. Covers easing (linear/easeIn/Out/InOut), custom UnitCurve (bezier, circular), springs (smooth/snappy/bouncy) and parameterized springs, interactiveSpring/interpolatingSpring, CustomAnimation, plus modifiers (delay, speed, repeat). Note: iOS 17 default is spring.
Quick tip for macOS app development: clear persisted UserDefaults (including SwiftUI @AppStorage) via Terminal with the defaults command. Delete the whole app domain (defaults delete com.example.MyApp) or a specific key, and apply the same to custom suites/app groups to reset state or test onboarding.
Guide to SwiftUI TimelineView for time-driven UI. Covers schedules: everyMinute, periodic(from:by:), and animation(minimumInterval:paused:) to refresh or drive effects. Uses TimelineView.Context date and cadence to adapt detail. Notes when to use Timer vs TimelineView.
Modern SwiftUI scrolling: set initial position with defaultScrollAnchor; drive via scrollPosition(_:anchor:) bound to ScrollPosition (id/edge/offset); read current item with viewID(type:). For raw offsets use onScrollGeometryChange. Lists still require ScrollViewReader.
How to style macOS window toolbars in SwiftUI: set windowToolbarStyle(.unifiedCompact or .expanded); hide title with toolbar(removing: .title) or showsTitle: false; hide title bar via windowStyle(.hiddenTitleBar); clear/color via toolbarBackgroundVisibility or toolbarBackground (+ toolbarColorScheme); control visibility with toolbarVisibility and windowToolbarFullScreenVisibility. Removing the title can reposition items.
Guide to background app refresh in SwiftUI: enable Background Modes, add task IDs in Info.plist, schedule BGAppRefreshTaskRequest (optional earliestBeginDate), and handle via .backgroundTask(.appRefresh(id)) with async work. Heuristics may skip runs; finish in ~30s. Test via LLDB; use background URLSession or BGProcessingTaskRequest for longer jobs.
Overview of SwiftUI's onChange(): Equatable-based change detection; iOS 14 API vs iOS 17 onChange(of:initial:_:) with no-arg and old/new closures; capture lists reflect new state; initial fires on first render; choose view vs scene; use Task to avoid main-thread blocking.
Embed SF Symbols in SwiftUI Text by interpolating Image(systemName:) in a string literal, or create a LocalizedStringKey and pass to Text. Modifiers on the interpolated Image don’t work—wrap Text(Image(...)) to style. No AttributedString support.
Announcement of "The SwiftUI Way" book by former Apple SwiftUI engineer Natalia Panferova. Guide focuses on production-level SwiftUI patterns vs anti-patterns, covering maintainable view structures, data dependencies, state management, performance optimization, and accessibility. Targets developers beyond tutorials who struggle with unexpected view updates and framework conflicts.
iOS 26 adds SwiftUI lineHeight(_:) via AttributedString.LineHeight. Covers presets (loose, tight, normal, variable) and methods multiple(factor:), leading(increase:), exact(points:). Compares with lineSpacing(_:). Notes Dynamic Type scaling; warns exact is fixed and may clip. Prefer lineHeight for finer typography.
animation(_:value:) can cause unintended animations in reusable SwiftUI containers. Use animation(_:body:) (iOS 17) to isolate which modifiers animate by scoping them in the closure (e.g., only opacity). This prevents accidental text/layout animations and keeps components predictable.
Shows how to customize Swift string interpolation by extending String.StringInterpolation with a generic appendInterpolation that takes any FormatStyle. Demonstrates inline Date formatting via .dateTime and notes you can reuse this pattern for validation, conditional logic, and domain‑specific rendering.
How to animate SF Symbols in SwiftUI using Symbols effects. Covers Indefinite, Discrete, Content Transition, and Transition groups with symbolEffect modifiers, contentTransition(.symbolEffect), and transition(.symbolEffect). Shows options (repeat, speed, iterative, reversing) and notes transitions work even without withAnimation. Takeaway: expressive, configurable icon animations with minimal code.
Quick tip: In SwiftUI, give SF Symbols an inset, cut-out look by applying a foregroundStyle with an inner shadow. Example: Image(systemName: "cloud.rain").symbolVariant(.circle).foregroundStyle(.indigo.shadow(.inner(radius: 2))). Adjust color/radius; best with rounded variants.
How to initialize and store @Observable classes in SwiftUI: keep models in @State so they persist across view rebuilds; avoid recreating them on every init. Defer heavy setup with task(id:). For shared, app-wide state, create in App and inject via environment. Initializers still evaluate on rebuilds.
UIKit auto-tracks Swift Observation: reads of @Observable in update methods trigger UI refresh. Use UIViewController.updateProperties() on iOS 26; on iOS 18 enable UIObservationTrackingEnabled and use viewWillLayoutSubviews(). Simplifies UIKit–SwiftUI state sharing; no withObservationTracking.
SwiftUI snapping: use scrollTargetBehavior(.paging) for page snaps (LazyHStack spacing=0). Or use .viewAligned + .scrollTargetLayout() to snap to items. Targets must fit; oversized items break snapping—consider a custom ScrollTargetBehavior.
iOS 26 adds SwiftUI’s Button(role: .close) for informational modals. Unlike .cancel, it implies no data loss and doesn’t auto‑dismiss—you still call dismiss(). Add it to a sheet toolbar to get the standard X button. Key APIs: Button(role: .close), @Environment(\.dismiss).
SwiftUI Fundamentals is refreshed for iOS 26 with the Liquid Glass look. It keeps focus on core mechanics—view composition, state flow, and layout—clarifies minor behavior changes, and re‑verifies all examples against current SwiftUI APIs.
On iOS 26, SwiftUI swipeActions now show both title and symbol for Button(title:systemImage:), stacked or side by side by row height. To get icon-only like before, set .labelStyle(.iconOnly) on the Button. Relies on SwiftUI label styling behavior.
Dynamic Type can cause SwiftUI Text to truncate at large sizes even in a ScrollView. Fix by applying fixedSize(horizontal: false, vertical: true) to let text wrap horizontally and expand vertically. Ensure the layout can grow vertically at accessibility sizes.
Launch recap for Breve shares iOS 26 SwiftUI techniques: immersive headers with backgroundExtensionEffect, a stretchy header via visualEffect, a Search tab (searchable) with Core Spotlight indexing, Liquid Glass sheets with morphing transitions, and AlarmKit timers + Live Activity. Notes: partial detents needed; no in‑app countdown API.
Forms and pushed views obscure SwiftUI Liquid Glass sheets. Hide Form with .scrollContentBackground(.hidden) at partial detents and toggle via presentationDetents(selection: $currentDetent). For destinations and navigationLink pickers, add .containerBackground(.clear, for: .navigation).
Explains SwiftUI’s new ConcentricRectangle (iOS 26): create via ConcentricRectangle or .rect(corners:.concentric), and define parent geometry with containerShape. Covers corner radius resolution, using isUniform for balanced corners (e.g., popovers), minimum radius fallback, and RoundedRectangularShape requirement.
Use Core Spotlight to surface app data in Spotlight and power in‑app search: index with CSSearchableItem/Index (async), deep link via onContinueUserActivity, avoid repeats with batch client state, improve rank via lastUsedDate/isUpdate, add a reindexing extension, and query with CSUserQuery (debounce, correct init, ranking).
SwiftUI on iOS/iPadOS 26 adds Liquid Glass search placements: use searchable() on NavigationStack/SplitView, restore .sidebar, or attach to detail. New DefaultToolbarItem(.search)+ToolbarSpacer and searchToolbarBehavior(.minimize). Tab(role: .search) + TabView.searchable inside a NavigationStack.
iOS 26 adds Liquid Glass sheets in SwiftUI. Include a partial detent in presentationDetents (e.g., .medium) to get the default look. Avoid presentationBackground(). For morphing, use matchedTransitionSource + navigationTransition(.zoom); needs NavigationStack. Beta 3 glitches.
Comprehensive guide to Apple's new AlarmKit framework introduced at WWDC 2025. Shows how to implement countdown timers that bypass silent mode and Focus restrictions, unlike standard notifications. Covers authorization flow with NSAlarmKitUsageDescription, creating AlarmAttributes with custom alerts, scheduling timers with AlarmManager, and building Live Activities for countdown display. Includes Dynamic Island integration with progress views and in-app timer management using alarmUpdates sequence. Key gotcha: requires nonisolated AlarmMetadata conformance in Xcode 26.
Swift 6.2 (iOS 26) makes enumerated() directly usable in SwiftUI List/ForEach via SE‑0459, which gives EnumeratedSequence Collection conformances. Show row numbers without Array(...). Don’t treat offset as an index or as id; use stable identity (e.g., id: \.element or \.element.id).
Create a stretchy header in SwiftUI using visualEffect() instead of tracking offsets in state. In the modifier, read GeometryProxy.frame(in: .scrollView).minY, clamp to ≥0, compute a scale from current height, and apply scaleEffect(anchor: .bottom). Reusable, no extra state; use in a ScrollView ignoring top safe area.
Explores SwiftUI’s new backgroundExtensionEffect() to extend mirrored, blurred content behind control layers. Demos: a NavigationSplitView detail image and card headers that use safeAreaInset with a gradient overlay for legibility. Reminder to test across themes/images.
Wrap views in ScrollView for Dynamic Type, but default bounce feels odd when content fits. On iOS 16.4+, use scrollBounceBehavior(.basedOnSize) on the ScrollView or its container to disable bounce until scrolling is needed—cleaner, more accessible SwiftUI layouts.
Guide to SwiftUI MeshGradient (iOS 18/macOS 15): build 2×2+ grids with points/colors in 0–1 space (can go outside), set background fill, tweak opacity, sculpt with BezierPoint controls, keep x/y ordering per row/column to avoid seams, and animate points via TimelineView.
Format values inline in SwiftUI Text via string interpolation. Use LocalizedStringKey’s format/style: .list for string arrays, .measurement for Measurement, .dateTime for static dates, .relative/.timer for live dates. Locale-aware output; apply monospacedDigit() to avoid jitter.
Quick Xcode tip: To make long function/initializer calls readable, put the cursor inside the parentheses and press Control (⌃)+M to split each argument onto its own line. If you first select the entire expression, Xcode also formats closures and collections.
Embed a custom font in a macOS app: add the font to Xcode (no target membership), copy it via a Copy Files build phase to Resources/Fonts, set ATSApplicationFontsPath=Fonts in Info.plist, then use NSFont(name:size:) or SwiftUI Font.custom. Use the font’s internal name.
Replace the default About panel with a fully custom SwiftUI window: build AboutView, show it via a Window scene and Environment.openWindow, and override CommandGroup(.appInfo). Fine‑tune using containerBackground, windowBackgroundDragBehavior, windowResizability(.contentSize), windowMinimizeBehavior(.disabled), and restorationBehavior(.disabled). Some APIs require newer macOS.
In SwiftUI, Image("name") defaults VoiceOver to the asset name. Add a localized string whose key equals the image name (via Localizable.strings or a String Catalog) and SwiftUI will use it as the accessibility label automatically—no accessibilityLabel() needed.
SwiftUI text color options: use foregroundStyle (ShapeStyle, gradients, hierarchical levels; iOS 15+) instead of deprecated foregroundColor. AttributedString colors ranges (solid only). tint affects controls/links, not plain Text. textRenderer (iOS 18) enables advanced glyph effects.
Swift Gems gets a major update for Swift 6.0/6.1, adding advanced tips on noncopyable types, static dispatch, metatype key paths, AsyncStream, TaskGroup, and typed throws—plus refreshed guidance on optionals/generics and collection/runtime performance. Targeted at experienced Swift devs.
SwiftUI Text concatenation (+) breaks localization: segments are translated separately, spaces are fragile, and translators can’t reorder. Use string interpolation in one Text so the String Catalog adds placeholders; you can still style the interpolated Text.
Swift method dispatch: Dynamic uses V-Tables (classes), witness tables (protocols), and Obj-C/C++ virtuals. Static for value types, final/private, and non-requirement protocol extension methods. Optimize with final/private, fewer protocol requirements, WMO; avoid Obj-C; profile in Instruments.
How to adapt images to Dynamic Type in SwiftUI: let SF Symbols scale with the view’s font (avoid resizable() to keep symbol behavior). Scale custom images via @ScaledMetric(relativeTo:). Use dynamicTypeSize and isAccessibilitySize to remove decorative images; use high‑res assets.
Custom SwiftUI environment values: pre–Xcode 16 you wrote an EnvironmentKey + EnvironmentValues extension. In Xcode 16, @Entry declares entries with defaults. Set via environment(_:_:); read with @Environment. Back-deploys to iOS 13+/macOS 10.15+.
Customize SwiftUI modal backgrounds with presentationBackground(_:), or a custom view via presentationBackground(alignment:content:). For Lists/Forms, reveal translucency using scrollContentBackground(.hidden) + listRowBackground(.clear). Control contrast with preferredColorScheme(_:). Translucency is stronger in sheets/covers than popovers.
Standard SwiftUI List/Lazy stacks stutter on very large macOS lists. Build a recyclable list: track visible rows with onScrollGeometryChange, place them via a custom Layout (OffsetLayout) + LayoutValueKey, and reuse views using fragment IDs. Reset local @State when IDs change. Faster, lower memory; works on iOS with fixed row height.
On macOS with SwiftUI, controlActiveState is deprecated in macOS 15. Use the appearsActive EnvironmentValue (true when the window is focused). Access via @Environment(.appearsActive) and observe with onChange to update UI or trigger actions when focus changes.
Announcing SwiftUI Fundamentals, a book that dives into how SwiftUI works under the hood: view updates, data flow, layout/size negotiation, state-driven navigation, animations and gestures, and key APIs/design patterns across iOS/macOS—so you can write efficient, maintainable code.
Create a macOS menu bar–only app with SwiftUI MenuBarExtra: replace WindowGroup, use .menuBarExtraStyle(.window), and host your UI in ContentView. Hide from Dock via Info.plist LSUIElement. Add a Quit overlay (NSApp.terminate). Use custom icon; resize NSImage before Image.
How to verify SwiftUI SceneStorage persists UI state (e.g., selected tab) across launches. In Simulator: run, change state, press Home, stop from Xcode, rerun. Force‑quitting from the app switcher clears SceneStorage, so avoid it when testing.
Create a reusable CaptureUUID that conforms to RegexComponent to type-safely capture UUIDs with Swift’s RegexBuilder. It matches hex-digit UUID groups, transforms the capture to UUID(uuidString:), throws on invalid input, and composes with Reference to extract IDs from paths.
WebSocket consumers in Django Channels handle one message at a time, so long-running async work blocks the queue. Using Django Channels Rest Framework, mark actions as detached with @action(detached=True) in an AsyncAPIConsumer to run them concurrently and keep other messages responsive.
Expose macOS Services from your app: implement an NSObject provider with @objc methods that read/write NSPasteboard, register via NSApplication.shared.servicesProvider, and declare NSServices in Info.plist. Verify with pbs -dump_pboard. Only one servicesProvider per app.
SwiftUI’s popover() defaults to a sheet on iPhone. On iOS 16.4+, apply presentationCompactAdaptation(.popover) to the view inside the popover’s content to prefer a popover in compact size classes. Example: ingredients list button. Takeaway: keep popovers on iPhone.
Add Launch at Login to a macOS SwiftUI app using SMAppService. Toggle calls mainApp.register()/unregister(). Check mainApp.status onAppear and when appearsActive changes to sync UI. Default off to meet App Review; read system status instead of persisting.
Pluralize in SwiftUI Text with Foundation’s automatic grammar agreement—fewer localized strings, no manual plural logic. Use the Markdown attribute: ^[\(count) book](inflect: true). SwiftUI parses LocalizedStringKey and inflects at render. iOS 15+, broader language support in iOS 18.
Guide to Codable for Swift enums: automatic synthesis for raw-value, case-only, and associated-value cases (unlabeled -> _0, _1; optionals omitted). Customize case and associated keys via CodingKeys, exclude values (need defaults), or implement encode/init for nonstandard formats.