20 Android Architecture Components Interview Questions and Answers

Android Architecture Components are a set of software libraries that help developers follow best practices when designing and building Android apps. They are designed to be used together, but can also be used independently. When applying for an Android development position, it is likely that you will be asked questions about Android Architecture Components. In this article, we review some common questions and how you should answer them.

Android Architecture Components Interview Questions and Answers

Here are 20 commonly asked Android Architecture Components interview questions and answers to prepare you for your interview:

1. What is Android Architecture Components?

Android Architecture Components is a set of libraries that help you design robust, testable, and maintainable apps. With these libraries, you can create apps that are more reliable and perform better. The libraries are available for use with Java and Kotlin.

2. Why do you think it’s important to use a framework like Android Architecture Components when building an app with Android Studio?

I think it’s important to use a framework like Android Architecture Components because it helps to keep your code organized and easy to maintain. It also helps to prevent errors and bugs from creeping into your code.

3. What are the main components of Android Architecture Components?

The main components of Android Architecture Components are the ViewModel, LiveData, and Room. The ViewModel is responsible for storing and managing UI-related data. LiveData is a data holder that can be observed by UI components. Room is a database library that provides an abstraction layer over SQLite.

4. Can you explain what data binding is and how it works in context of Android Architecture Components?

Data binding is a process that allows you to automatically synchronize your UI with your data model. It is a key part of the Android Architecture Components, and it ensures that your UI always reflects the latest state of your data. Data binding is achieved by using a data binding library, which generates a binding class for each data model. This binding class contains all the necessary information to automatically update the UI whenever the data model changes.

5. How can you implement MVVM architecture using Android Architecture Components?

You can implement MVVM architecture using Android Architecture Components by using the ViewModel class to store and manage your data, the LiveData class to handle data changes, and the Data Binding Library to bind your data to your UI.

6. How would you create your own custom lifecycle-aware component?

You would create a custom lifecycle-aware component by implementing the LifecycleOwner interface and the LifecycleObserver interface. The LifecycleOwner interface provides a way for you to manage the lifecycle of your component, while the LifecycleObserver interface allows you to observe and react to changes in the lifecycle of your component.

7. When should you use ViewModel over Activity or Fragment?

ViewModel is designed to store and manage UI-related data in a lifecycle-conscious way. This means that the data stored in the ViewModel survives configuration changes such as screen rotations. As a result, ViewModel is a good choice for storing data that you would like to keep around for the duration of the app’s execution, such as a user’s login credentials.

8. What are some benefits of using Room instead of SQLite directly?

Room provides an abstraction layer over SQLite, which makes it easier to work with databases in Android. Room also allows you to compile database queries at compile time, which can help to catch errors early. Additionally, Room supports LiveData, which can help to keep your UI updated automatically when the underlying data changes.

9. Do you need to write any code for implementing Paging?

No, you don’t need to write any code for implementing Paging. The Paging library takes care of loading data in pages and displaying it in your app.

10. What does “paging” mean in context of Android Architecture Components?

Paging is a way of loading data in chunks, or pages, rather than all at once. This can be helpful when dealing with large data sets, as it can help to improve performance and avoid loading more data than is necessary. Paging is a key component of the Android Architecture Components, and is used in conjunction with the other components to help create a more efficient and effective way of loading data.

11. How do you handle configuration changes with LiveData?

When a configuration change occurs, LiveData will automatically deliver the most recent data to the active observers. This means that you don’t need to do anything special to handle configuration changes, as LiveData will take care of everything for you.

12. How do you convert a MutableLiveData object into an immutable one?

You can use the toImmutable() extension function.

13. What are the main differences between Observable and LiveData objects?

The main difference between Observable and LiveData objects is that LiveData objects are lifecycle-aware. This means that they will automatically update themselves when the activity or fragment they are associated with changes state. Observable objects are not lifecycle-aware and will not automatically update themselves.

14. Is it possible to change the default behavior of Data Binding Library? If yes, then how?

Yes, it is possible to change the default behavior of Data Binding Library. You can do so by creating a custom BindingAdapter.

15. Is it possible to access view models from other modules in your application? If yes, then how?

Yes, it is possible to access view models from other modules in your application. You can do this by using the ViewModelProvider class, which provides a way to access view models by using a key that is associated with the view model.

16. What are some ways to add observers to LiveData objects?

You can add observers to LiveData objects in a few different ways. You can use the observe() method to add an observer to a LiveData object, or you can use the observeForever() method to add an observer that will never be removed. You can also use the LiveData.observe() method to add an observer to a LiveData object that will be removed when the LifecycleOwner is destroyed.

17. What happens if you try to observe a live data object that has not been initialized yet?

If you try to observe a live data object that has not been initialized yet, you will get a null value.

18. What is the best way to set up communication between two fragments?

The best way to set up communication between two fragments is to use a FragmentManager. This will allow you to add, remove, and attach fragments to each other as needed.

19. What are the different threading options available when working with LiveData objects?

There are two different types of threads that can be used when working with LiveData objects: the main thread and a background thread. The main thread is the UI thread, and it is where all UI updates must be made. The background thread is used for all other operations, such as fetching data from a remote server.

20. What are some drawbacks of using LiveData as compared to RxJava?

While LiveData has the advantage of being lifecycle-aware (meaning it will automatically clean up after itself when the associated lifecycle is destroyed), it is not as flexible as RxJava when it comes to composing and transforming data. LiveData also does not support backpressure, meaning that it can potentially drop events if it is not able to keep up with the rate at which they are being emitted.