30 SwiftUI/iOS Blog Topics - Real-World Examples & Code Snippets

Debugging & Performance (5 topics)

1. Print What Changed: Debug SwiftUI View Updates Like a Pro

Real-world scenario: Your expense split app list is re-rendering constantly, draining battery. Use Self._printChanges() to find the culprit property causing unnecessary redraws.

var body: some View {
    let _ = Self._printChanges()
    ExpenseListView(expenses: expenses, totalAmount: total)
}
// Output: ExpenseListView: @State expenses changed.

2. Why Is My SwiftUI View Rendering 10 Times? Using Instruments to Find the Culprit

Real-world scenario: Sleep tracker showing lag when scrolling through 100+ sleep entries. Use SwiftUI Instruments template to identify excessive body calls.

3. The @State vs @StateObject Bug That Cost Me 2 Hours: Memory Leaks in SwiftUI

Real-world scenario: Fitness app creating new HealthKit manager instances on every view update, causing memory to spike from 50MB to 300MB.

4. Debug Your Network Calls Without Proxyman: Using URLProtocol for Request Inspection

Real-world scenario: API calls failing in production but working in dev. Implement custom URLProtocol to log all requests in-app.

5. The Hidden po Commands That Saved My Debugging Session

Real-world scenario: App crashes when user taps notification. Using po UIApplication.shared.keyWindow?.rootViewController to inspect view hierarchy in lldb.

Design Patterns (6 topics)

6. Repository Pattern: Stop Mixing Core Data Logic in Your SwiftUI Views

Real-world scenario: Expense split app with Core Data fetch requests scattered across 5 different views. Refactor to repository pattern for testability.

7. The Coordinator Pattern for SwiftUI Navigation (That Actually Works in 2025)

Real-world scenario: Managing complex navigation in fitness app: onboarding → home → workout detail → workout in progress → workout complete.

8. Dependency Injection in SwiftUI Without Third-Party Frameworks

Real-world scenario: Switching between mock and real HealthKit managers for testing. Using @EnvironmentObject and protocol-based injection.

9. MVVM is Not Enough: When to Use Interactors in SwiftUI Apps

Real-world scenario: Sleep tracker’s “analyze sleep quality” feature has 200+ lines of business logic in ViewModel. Extract to Interactor.

10. The Service Locator Pattern: Managing Global Dependencies (AnalyticsManager, NetworkManager)

Real-world scenario: 15 different views need access to analytics and network managers. Implement lightweight service locator vs passing through environment.

11. State Machine Pattern for Complex UI Flows (App Onboarding, Multi-Step Forms)

Real-world scenario: User onboarding with 5 steps, each step can fail, skip, or complete. Using enum-based state machine.

SwiftUI Tips & Tricks (8 topics)

12. The .task() Modifier That Replaced My onAppear + .onDisappear Cleanup Code

Real-world scenario: Fetching user’s expenses when view appears and cancelling network request on disappear. Task handles both automatically.

13. Custom View Modifiers: Stop Repeating the Same 5 Lines of Code

Real-world scenario: Every card in expense app has same shadow, corner radius, padding. Create .cardStyle() modifier.

14. The @AppStorage Trick for Feature Flags Without Backend

Real-world scenario: A/B testing new expense split algorithm. Toggle between old/new logic using AppStorage.

15. PreferenceKey: How I Built a Dynamic Tab Bar That Knows Its Content Height

Real-world scenario: Custom tab bar that adjusts height based on longest tab title. Use PreferenceKey to bubble up height from children.

16. The GeometryReader Hack for Responsive Design (Without Breaking Layout)

Real-world scenario: Sleep tracker charts need to resize for iPhone SE vs iPhone 15 Pro Max. Using GeometryReader without causing layout issues.

17. Lazy Loading in SwiftUI: Stop Loading 1000 Rows at Once

Real-world scenario: Expense list with 500+ items causes memory spike. Implement LazyVStack with pagination and prefetching.

18. The .onChange Modifier: Replacing Combine Subscriptions in SwiftUI

Real-world scenario: Update chart when date range changes. Using .onChange(of: dateRange) instead of Combine sink.

19. Custom Animations: The AnimatableModifier That Made My Charts Smooth

Real-world scenario: Bar chart bars jump to new values. Implement AnimatableModifier for smooth transitions.

HealthKit & System Integration (3 topics)

20. HealthKit Authorization: The Right Way to Ask for 15+ Permissions

Real-world scenario: Sleep tracker needs sleep data, heart rate, steps. Batching permissions vs one-by-one UX considerations.

21. Background Fetch for HealthKit: Syncing Sleep Data While App Is Closed

Real-world scenario: User tracks sleep with Apple Watch. App needs to fetch new sleep data at 8 AM daily for analysis.

22. Core Data + CloudKit: Syncing User’s Expenses Across iPhone and iPad

Real-world scenario: User splits expense on iPhone, expects to see it on iPad immediately. Handling merge conflicts.

Error Handling & Edge Cases (3 topics)

23. The Result Type: Cleaner Error Handling Than do-catch Everywhere

Real-world scenario: Network layer with 10 API endpoints. Using Result<T, APIError> for consistent error handling.

24. Graceful Degradation: When HealthKit Permission Is Denied

Real-world scenario: Sleep tracker’s core feature needs sleep data, but user denies permission. Fallback to manual entry.

25. The Force Unwrap That Crashed in Production: Lessons in Optional Handling

Real-world scenario: UserDefaults.standard.string(forKey: "userId")! crashes when user clears app data. Defensive programming.

Testing & Code Quality (2 topics)

26. Testing SwiftUI Views Without UI Tests: ViewInspector Basics

Real-world scenario: Testing expense split calculation displayed correctly in view without slow UI tests.

27. The Async/Await Refactor That Reduced My Code by 40%

Real-world scenario: Replacing completion handlers in networking layer with async/await. Before/after comparison.

App Store & Production (3 topics)

28. The In-App Review Prompt That Increased My Ratings by 3x

Real-world scenario: Prompting after user successfully splits 3rd expense (moment of value) vs random prompt on app open.

29. Feature Flags Using Remote Config: Gradual Rollout Without App Store Review

Real-world scenario: New sleep analysis algorithm. Roll out to 10% of users first, monitor crash rate before 100% rollout.

30. The Analytics Event That Told Me Users Were Stuck (And How I Fixed It)

Real-world scenario: 40% of users abandon expense split on “Add Friends” screen. Analytics revealed confusing UI copy.

Notes: