Introduction

iOS is the most famous mobile operating system and is well known by every person. iOS stands for “iPhone Operating System.” Apple devices are embedded with this operating system, and after Android, iOS is considered the second most mobile operating system globally. Many of the apple products like the iPhone, iPad, and iPod are operated using iOS.

iOS comes with several features, and some of them are listed below:

1. It provides multitasking capabilities.
2. Network integrations are very easy.
3. Users can store data on Apple’s iCloud service.
4. iOS is a closed system.
5. iOS-powered are harder to hack.

iOS Interview Questions for Freshers

1. Elaborate on iOS with its architecture.
2. What do you understand by the term ‘property’ in iOS?
3. What is Cocoa Touch?
4. Explain Stored and computed properties.
5. Differentiate between atomic and non-atomic properties?
6. What is the default for synthesized properties?
7. Explain the different application states for iOS.
8. Who is an iOS developer?
9. Explain the responsibilities of an iOS developer.
10. Compare and contrast Android and iOS.
11. What is Deep linking in iOS?
12. What do you understand by Grand Central Dispatch in iOS?
13. What do you know about ARC (Automatic Reference Counting)?
14. Highlight the difference between Cocoa and Cocoa Touch.
15. Name the various programming languages that are used for iOS development.
16. Which framework is used to build an application’s interface for iOS?
17. What are the different ways to achieve concurrency in iOS?
18. Define the terms ‘Threads’ and ‘Operation Queues.’
19. What is the main difference between App ID and Bundle ID?
20. Define Event Handling?
21. Explain the terms: SpriteKit and SceneKit framework concerning game development.
22. State the difference between assigning and retaining keywords.
23. What do you understand by Multiplatform support?
24. Tell me the syntax of the swift language.
25. Explain NSString with an example.
26. What is an unnamed category?
27. Which application thread is used to access UIKit classes?
28. How will you respond to state transitions on your app?
29. Name the UI Elements in iOS.
30. Explain TVMLKit.
31. Explain Grand Central Dispatch.
32. Define Dynamic Dispatch.
33. Explain the differences between retaining and assigning.
34. What new features are added in iOS 9?

iOS Interview Questions for Experienced

1. Explain the Objective-C in OS.
2. List down the most popular data types that come under objective-C.
3. What is Swift in iOS?
4. Elaborate NSError in Swift?
5. Explain some characteristics of Swift.
6. Explain Enum or Enumerations in Swift.
7. Describe the lazy property in iOS.
8. Define generics and write down their usage.
9. Define the term ‘Dictionary’ in context with Swift.
10. What is the importance of Design Patterns?
11. Name the popular Design patterns that are used in iOS.
12. What is the role of the Facade in Model-View-Controller?
13. Name the JSON framework that is supported by iOS.
14. Explain iBeacons in iOS.
15. Compare the two terms KVC and KVO in Swift.
16. Explain Test-Driven-Development?
17. What is the function of the completion Handler?
18. Differentiate among the following: Strong, weak, read-only, and copy.
19. What do you know about the term Dynamic Dispatch?
20. Elucidate @dynamic and @synthesize commands in Objective -C?
21. How will you implement storage and persistence in iOS?
22. Define Synchronous and asynchronous tasks in iOS.
23. What is the way of executing asynchronous tasks in iOS?
24. Which database is suitable for implementing complex querying mechanisms?
25. Define ‘Disk Storage’?
26. How is memory management done in iOS?
27. Explain Guard Statement.
28. Explain the relation between Ivar and @property.
29. Explain Swift’s pattern matching techniques.
30. What is the NSURL Connection class?
31. Define the types and use cases of NSURL.
32. What is an abstract class in Cocoa?
33. Differentiate between ‘App ID’ and ‘a Bundle ID’? Explain the use of each.
34. Mention some of the advantages of Swift.
35. What is the use of reuseIdentifier?
36. What is the benefit of setting reuseIdentifier into a non-nil value?
37. Explain “Model-View-Controller”?
38. What is a plist?
39. Does Objective-C come with private methods?
40. Explain the process of preventing the iOS 8 app’s streaming video media from being captured by Quick Time Player on Yosemite during screen recording.
41. In what conditions atomic properties are used over non-atomic properties and vice-versa?
42. What is the use of deinit in Swift?
43. What is a QOS?
44. What do you understand by deadlock?
45. Describe the functions of managed object context.
46. How will you prioritize usability in Design?
47. Differentiate between a frame and a bound?
48. Explain a singleton class.
49. What are the different ways to specify the layout of elements in UIView?
50. Write the advantages of the Realm framework.

iOS Advanced level Interview Questions

1. What are the various rendering options for JSONSerialization?
2. What type of functionality is provided by managed object context?
3. Elucidate ‘strong’ and ‘weak’ references?
4. How are memory management and avoidance of memory leaked are achieved?
5. Name the APIs that are used for battery-efficient location tracking.
6. Mention the Realm benefits?
7. Explain the observer pattern.
8. Explain the Adapter pattern.
9. What is a Responder chain?
10. What is Code coverage?
11. Name the method used to perform final utilization before displaying the app to the user.
12. Which command is used to open the Code Snippet Library in Xcode?
13. Name the two different smart groups in Xcode.
14. Differentiate between Viewdidload and Viewdidappear?
15. What is method swizzling?
16. In what situations is an app said to be not running the state?