iOS Interview Questions Part 2

In this post, I want to write 10 iOS interview questions you might face, to help you ace your next interview. This is part number two.
Check part number one to cover more questions.

iOS Interview Questions Part 1

Question 1

What is the difference between a code signing certificate and a provisioning profile?

Answer 1

A code signing certificate assures users that your application is from a known source that users can trust. In contrast, a provisioning profile enables you to launch your app on a specific device and use certain services.

Question 2

What is an XCTestCase?

Answer 2

The class you use to define groups of unit tests with optional setup and teardown steps that run before and after each test.

Question 3

You are trying to write a method, isInFirstQuadrant, that returns true if a point (x,y) is in the first quadrant by comparing it with the instance constant properties, x and y:

struct Point {
    let x = 0.0, y = 0.0
    func isInFirstQuadrant(x: Double, y: Double) -> Bool {
        if x > x, y > y {
            return true
        }
        return false
    }
}

The following call to the method returns false when it should return true because the point, (5,6), is in the first quadrant:

let point = Point()
point.isInFirstQuadrant(x: 5, y: 6)

How would you modify the method, isInFirstQuadrant, to behave the way you expect it to?

Answer 3

func isInFirstQuadrant(x: Double, y: Double) -> Bool {
    if x > self.x, y > self.y {
        return true
    }
    return false
}

Question 4

What is the difference between actionable notifications and regular push notifications?

Answer 4

Actionable notifications let the user respond to a notification without launching your application, whereas regular push notifications require the user to launch the app to respond to notifications.

Question 5

You add a new scene to your iOS application’s storyboard. You also add a new view controller class called SecondViewController to your Xcode project. You override the viewDidLoad method of SecondViewController and write custom code that should run after the new scene loads. When you test your application in a simulator, the custom code does not run. Why?

Answer 5

You forgot to set the Class in the Identity Inspector of the new scene’s view controller to SecondViewController.

Question 6

Besides throwing functions, what is another form of error propagation in Swift?

Answer 6

Throwing initializers

Question 7

What problem can you accomplish by implementing a class that conforms to the UNUserNotificationCenterDelegate protocol?

Answer 7

Processing notifications that arrive when your application is running in the foreground

Question 8

You configured your backend server to send push notifications to your application while it is in the background. How would you handle those notifications for your iOS app?

Answer 8

Write code in the app delegate’s application(_:didReceiveRemoteNotification:fetchCompletionHandler:) method that performs the appropriate processing actions in the background.

Question 9

What is true about background notifications?

Answer 9

A background notification is a remote notification that does not display an alert, play a sound, or place a badge on your application’s icon.

Question 10

You submit your application for review. What happens next?

Answer 10

Your app has the status of Waiting for Review and you cannot upload or edit screenshots or app previews.

As you prepare for your iOS interview, remember that the key to success is knowing the right answers and the concepts behind them. By familiarizing yourself with the common questions we’ve covered and practicing your problem-solving skills, you’ll be better equipped to tackle any challenge that comes your way. Interviews are as much about demonstrating your thought process and communication skills as they are about technical knowledge. So, take a deep breath, stay calm, and showcase the passion and expertise that make you a standout iOS developer. Good luck, and may your next interview lead to exciting new opportunities in your career!