NexEver Senior IOS Developer Interview Questions and Answers

MVVM (Model-View-ViewModel) is a design pattern used in Swift to separate the user interface logic from the business logic.

• MVVM divides the code into three main components: Model, View, and ViewModel.

• Model represents the data and business logic of the application.

• View displays the data and interacts with the user.

• ViewModel acts as a mediator between the Model and View, handling the logic for the View.

• MVVM helps in maki...read more

Multithreading is the ability of a CPU to execute multiple threads concurrently, allowing for improved performance and responsiveness in applications.

• Multithreading allows multiple tasks to be executed simultaneously on a single CPU core.

• It can improve performance by utilizing idle CPU time for other tasks.

• Examples include running background tasks while the main thread handles user interactions in an iOS app.

App Life Cycle refers to the sequence of events that occur from the time an app is launched until it is terminated.

• App is launched by user or system

• App enters foreground and becomes active

• App enters background when user switches to another app or locks the device

• App may be terminated by the system to free up resources

• App can be brought back to foreground by user or system events

Extension of enum allows adding new cases, computed properties, and methods to an existing enum type.

• Extensions can be used to add new functionality to existing enum types without modifying their original implementation.

• New cases, computed properties, and methods can be added to an enum using extensions.

• Extensions can also be used to conform an enum to a protocol.

Delegate methods of URL session are used to handle various events during network requests.

• Delegate methods are used to handle authentication challenges, background session events, and data tasks.

• Examples include URLSessionDelegate, URLSessionDataDelegate, URLSessionTaskDelegate.

• Delegate methods can be used to handle redirects, caching policies, and response validation.

SSL pinning is a security measure used to prevent man-in-the-middle attacks by validating the server's SSL certificate.

• Implement SSL pinning by embedding the server's SSL certificate within the app's code.

• During the SSL handshake, compare the server's certificate with the embedded certificate to ensure they match.

• If the certificates match, the connection is considered secure and the data exchange can proceed.

• SSL pinnin...read more

Classes are reference types, structs are value types. GCD is low-level API, Operation queue is high-level API for concurrency.

• Classes are reference types, stored on the heap. Structs are value types, stored on the stack.

• GCD is a low-level API for managing concurrent operations. Operation queue is a high-level API built on top of GCD.

• GCD provides a simple and efficient API for dispatching tasks to a queue. Operation que...read more