20 SwiftUI Interview Questions and Answers

If you’re applying for a position that involves SwiftUI, you’re likely to encounter questions about the framework during your job interview. SwiftUI is a user interface toolkit that allows developers to create views in Swift code. It is important to be able to confidently answer questions about SwiftUI in order to demonstrate your knowledge and experience with the framework. In this article, we discuss some common SwiftUI questions and how you should answer them.

SwiftUI Interview Questions and Answers

Here are 20 commonly asked SwiftUI interview questions and answers to prepare you for your interview:

1. What is SwiftUI?

SwiftUI is a new framework that Apple introduced in WWDC 2019. It is a declarative UI framework that allows developers to create beautiful and responsive user interfaces with very little code.

2. What are the benefits of using SwiftUI over other UI tools?

SwiftUI provides a number of benefits over other UI tools, chief among them being its declarative syntax, which makes code more readable and easier to maintain. Additionally, SwiftUI is designed to work seamlessly with existing Swift code, making it easy to integrate into existing projects. Finally, SwiftUI is backed by Apple, which means that it will continue to receive support and updates going forward.

3. Can you explain what a View is in context with SwiftUI?

A View is a struct that represents a visual element of your app. You can create custom views by combining existing views, and adding your own modifiers to tailor them to your needs.

4. What’s the difference between an @ObservableObject and an @EnvironmentObject in SwiftUI?

An @ObservableObject is a class that conforms to the ObservableObject protocol. This protocol has one requirement: a property called objectWillChange. This property is used to notify SwiftUI of any changes to the object so that the UI can be updated. An @EnvironmentObject is a property wrapper that injects an object into the environment of a view. This means that the object will be available to all views that are descendants of the view that defines the @EnvironmentObject.

5. How can you use the @State property wrapper to create user input forms in SwiftUI?

The @State property wrapper can be used to create user input forms in SwiftUI by binding the value of a text field to a state variable. This will allow the text field to update its value as the user types and will also save the value of the text field when the user finishes editing it.

6. How do you declare properties that need to be accessed by multiple views at once in SwiftUI?

In SwiftUI, you can use the @EnvironmentObject property wrapper to declare properties that need to be accessed by multiple views. This will make the property available in the environment, and any view can access it by using the $ operator.

7. What types of data can be stored in a SwiftUI state variable?

A SwiftUI state variable can store any type of data that can be represented as a value type. This includes simple data types like integers and strings, as well as more complex data types like arrays and dictionaries.

8. How do you handle asynchronous tasks in SwiftUI?

There are a few ways to handle asynchronous tasks in SwiftUI. One way is to use the DispatchQueue class to run tasks on a background thread. Another way is to use the OperationQueue class to manage and schedule tasks.

9. In your opinion, how would SwiftUI change the way we build apps for iOS devices?

SwiftUI would allow for a more declarative and reactive way of building apps for iOS devices. This would potentially lead to apps that are more responsive and easier to maintain and update.

10. What’s the best way to manage app logic in SwiftUI?

There is no one-size-fits-all answer to this question, as the best way to manage app logic in SwiftUI will vary depending on the specific needs of your app. However, some tips on how to manage app logic in SwiftUI include using ViewModifiers to encapsulate logic, using environment objects to share data between views, and using Combine to manage asynchronous tasks.

11. What’s the advantage of using the MVVM architecture when building SwiftUI applications?

The advantage of using the MVVM architecture is that it helps to keep the code clean and easy to understand. It also makes it easier to unit test the code.

12. Is it possible to combine different view styles into one single view in SwiftUI? If yes, then how?

Yes, it is possible to combine different view styles into one single view in SwiftUI. This can be done by using the Group view. The Group view allows you to group multiple views together and treat them as if they were one single view. This can be useful for combining different styles together or for creating more complex layouts.

13. Why should you prefer structs over classes when working with SwiftUI?

Structs are value types, which means that they are copied when they are passed around in your code. This can be more efficient than using reference types (classes), which are passed by reference and can therefore be more expensive to work with. Additionally, structs are easier to reason about than classes because they have a clear and predictable lifecycle.

14. Why should you pay attention to the performance of your code when working with SwiftUI?

Because SwiftUI is a declarative UI framework, your code will be run multiple times as the framework recomputes the state of your views. If your code is not performant, this can lead to a lot of wasted time and resources.

15. How does SwiftUI compare to Apple’s previous UI toolkits like Cocoa Touch or AppKit?

SwiftUI is a brand new UI toolkit that was introduced with iOS 13. It is designed to be a more modern and declarative way to build user interfaces for Apple platforms. In comparison to Cocoa Touch and AppKit, SwiftUI is much easier to learn and use. It also provides better performance and is more flexible when it comes to customizing UI elements.

16. What are some of your favorite new features introduced in Swift 5.1?

I absolutely love the new string interpolation feature introduced in Swift 5.1. It makes it so much easier to create complex strings, and I think it’s really going to help with code readability. I’m also a big fan of the new compactMapValues() method, which makes it easier to work with dictionary values that may be nil.

17. What are shape objects used for in SwiftUI?

Shape objects are used to draw shapes in SwiftUI. You can use them to draw simple shapes like circles and rectangles, or more complex shapes like polygons and paths.

18. What are modifiers used for in SwiftUI?

Modifiers are used to change the appearance or behavior of a view in SwiftUI. For example, you can use modifiers to change the font size of a view, add a border to a view, or make a view respond to user input.

19. What is the role of containers in SwiftUI?

Containers are one of the key building blocks in SwiftUI. They allow you to group together multiple views, and can be used to provide common layout options or behaviors to all views within the container. For example, you could use a container to stack views on top of each other, or to apply a common background color to all views within the container.

20. What do you understand about the @Binding property wrapper?

The @Binding property wrapper is used to create a two-way binding between a view and its underlying model. This means that when the model changes, the view will update to reflect the change, and vice versa. This is useful for keeping the UI in sync with the underlying data.