iOS Development IOS App Developer 3

Question 1

Which SwiftUI container arranges child views vertically?

Accepted Answer

VStack

Answer

VStack stacks its child views top to bottom.

Question 2

What is the purpose of the Codable protocol in Swift?

Accepted Answer

To enable encoding and decoding to formats like JSON

Answer

Codable combines Encodable and Decodable for serialization to and from formats such as JSON.

Question 3

In MVVM architecture, what is the primary responsibility of the ViewModel?

Accepted Answer

Holding presentation logic and state for the view

Answer

The ViewModel exposes presentation state and logic, decoupling the view from the model.

Question 4

Which Xcode tool helps you detect memory leaks and performance issues at runtime?

Accepted Answer

Instruments

Answer

Instruments profiles apps for leaks, allocations, time, and other runtime metrics.

Question 5

What does the @Published property wrapper require its enclosing type to conform to?

Accepted Answer

ObservableObject

Answer

@Published is used inside an ObservableObject to emit changes to subscribers.

iOS Development Practice Test