iOS Development IOS App Development Fundamentals 4

Question 1

Which property wrapper passes a mutable reference to state owned by a parent view?

Accepted Answer

@Binding

Answer

@Binding creates a two-way connection to state that is owned elsewhere, typically by a parent view.

Question 2

What is Grand Central Dispatch (GCD) primarily used for in iOS?

Accepted Answer

Concurrent and asynchronous task execution

Answer

GCD manages the execution of tasks across queues to handle concurrency and keep the main thread responsive.

Question 3

Why should UI updates always be performed on the main thread?

Accepted Answer

UIKit/SwiftUI are not thread-safe for UI work off the main thread

Answer

UI frameworks require updates on the main thread because they are not thread-safe, and off-main updates cause crashes or glitches.

Question 4

Which framework provides on-device persistent storage with an object graph in modern iOS apps?

Accepted Answer

Core Data

Answer

Core Data manages an object graph and provides persistence for structured app data.

Question 5

What does the 'guard' statement do in Swift?

Accepted Answer

Exits early if a condition is not met

Answer

A guard statement requires a condition to be true to continue; otherwise it exits the current scope early.

iOS Development Practice Test