Essential iOS Interview Questions for 2025 Quiz

Test your understanding of key iOS interview topics with this quiz covering Swift fundamentals, UIKit, SwiftUI, app lifecycle, memory management, and common architectural patterns—perfect for iOS developer interview preparation.

1. Value and Reference Types

   Which of the following is a value type in Swift, meaning each variable gets its own unique copy? For example, changing one copy won’t affect another.

   1. ArrayList
   2. Struct
   3. NSObject
   4. Class

2. Optional Chaining

   What is the result of using optional chaining in Swift, such as user?.profile?.name, if 'profile' is nil?

   1. It returns nil
   2. It causes a crash
   3. It always returns a default value
   4. It returns an error

3. Weak References

   Why would you use a 'weak' reference in Swift, such as when declaring delegates?

   1. To increase performance
   2. To make variables immutable
   3. To prevent retain cycles
   4. To allow direct access to memory

4. UIKit vs. SwiftUI

   What is a key difference between UIKit and SwiftUI for building iOS interfaces?

   1. SwiftUI does not support views
   2. UIKit is only for Android
   3. SwiftUI uses a declarative approach
   4. UIKit requires coding in Python

5. App Lifecycle States

   Which state means an iOS app is running in the background but not executing code, such as after hitting the Home button?

   1. Foreground
   2. Active
   3. Terminated
   4. Suspended

6. Auto Layout in iOS

   How does Auto Layout help developers design responsive interfaces in iOS apps?

   1. By drawing views pixel by pixel
   2. By importing views from Photoshop
   3. By defining constraints for positioning and sizing views
   4. By using only fixed size frames

7. Memory Leaks

   What is a common cause of memory leaks in iOS applications that can be prevented with 'weak' or 'unowned' references?

   1. Memory mapping
   2. Retain cycles
   3. Loose typing
   4. Value copying

8. Architectural Patterns

   Which architectural pattern is most likely to produce a 'Massive View Controller' problem in iOS development?

   1. VIPER
   2. MVC
   3. Singleton
   4. MVNN

9. Optimizing Table Views

   Which technique improves the performance of a table view by reusing off-screen cells instead of creating new ones?

   1. drawRect()
   2. dequeueReusableCell
   3. cellSetup()
   4. reloadAllRows

10. Reactive Programming

    Which Apple framework allows you to handle asynchronous events using Publishers and Subscribers in a more composable way than delegation?

    1. EventLoop
    2. ThreadKit
    3. Combine
    4. AsyncCore