Looking for the best Android interview questions to ask potential candidates? You’re in the right place.

As the Android platform has become increasingly popular, so has the demand for skilled Android developers. To find the best candidates for your team, you need to ask the right questions.

Android development can be complex, so you’ll want to look for candidates who have a strong interest in mobile technology and are able to think outside the box. You should also focus on their portfolios and past experience to get an idea of their skillset.

And of course, it wouldn’t hurt to give your candidates a project assignment to test their abilities.

To help you out, we’ve compiled a list of the best interview questions to ask Android developers. With these questions, you’ll be able to assess whether or not a candidate has what it takes to be a valuable asset to your team.

Best Android Interview Questions

Let’s start with understanding what Android is all about. Android is an open-source operating system that is used primarily on mobile devices, such as cell phones and tablets.

It is a Linux kernel-based system that’s been equipped with rich components that allow developers to create and run apps that can perform both basic and advanced functions.

It was designed for touchscreen mobile devices such as smartphones and tablets. A consortium of developers known as the Open Handset Alliance developed Android, with Google commercially sponsoring it. They unveiled Android in November 2007 and HTC Dream launched it in September 2008.

50 Android Interview Questions You Should Ask

Now that we have a basic understanding of Android, let’s move on to the interview questions.

General Interview Questions

1. What is your experience with Android development?

This question will give you an idea of the candidate’s level of experience. If they’re relatively new to the field, you can ask them about their background and what drew them to Android development.

2. What are some of the most challenging issues you’ve faced with Android development?

This question will help you gauge the candidate’s problem-solving skills. You want to hire someone who is able to troubleshoot and find creative solutions to difficult problems.

3. What are some of the best practices you follow when coding for Android?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re following best practices so that you can avoid any potential problems down the road.

4. What are your thoughts on the Android platform?

This question will give you an idea of the candidate’s understanding of the Android platform. You want to make sure that they’re familiar with its capabilities and limitations.

5. Do you have any experience with Android Studio?

Android Studio is the official IDE for Android development. This question will help you gauge the candidate’s level of experience with the platform.

6. Do you have any experience with other IDEs?

While Android Studio is the official IDE, there are other IDEs that can be used for Android development. This question will help you gauge the candidate’s understanding of different IDEs and their capabilities.

7. What are your thoughts on using third-party libraries?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using third-party libraries and how to best integrate them into their code.

8. What are your thoughts on version control?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using version control systems, such as Git or SVN.

9. What are your thoughts on Continuous Integration?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using Continuous Integration tools, such as Jenkins or Travis CI.

10. Do you have any experience with testing?

This question will help you gauge the candidate’s understanding of best practices. You want to make sure that they’re familiar with different types of testing, such as unit testing and acceptance testing.

11. What is your experience with the Android SDK?

This question will help you gauge the candidate’s level of experience with the Android SDK. If they’re relatively new to the field, you can ask them about their background and what drew them to Android development.

12. What are your thoughts on the Android Support Library?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using the Android Support Library and how it can benefit their code.

13. What are your thoughts on Fragments?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using Fragments and how they can benefit their code.

14. What are your thoughts on the Android Architecture Components?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using the Android Architecture Components and how they can benefit their code.

15. What are your thoughts on the Android Design Support Library?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using the Android Design Support Library and how it can benefit their code.

16. Do you have any experience with Material Design?

Material Design is a design language developed by Google. This question will help you gauge the candidate’s level of experience with the platform.

17. What are your thoughts on using the Android NDK?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with using the Android NDK and how it can benefit their code.

18. Do you have any experience with OpenGL?

OpenGL is a cross-platform graphics API. This question will help you gauge the candidate’s level of experience with the platform.

19. What are your thoughts on performance optimization?

This question will give you an idea of the candidate’s understanding of best practices. You want to make sure that they’re familiar with performance optimization techniques and how they can benefit their code.

20. Do you have any experience with security best practices?

This question will help you gauge the candidate’s level of experience with the Android platform. You want to make sure that they’re familiar with common security risks and how to best mitigate them.

Technical Interview Questions

21. Describe the Android Framework

The Android Framework contains all the classes and methods that developers need to write applications for the Android environment.

It includes a wide variety of classes, from low-level classes that handle memory management and threading, to high-level classes that manage the user interface and application data.

22. What is an Activity?

An activity is a single, focused thing that the user can do. Almost all activities interact with the user, so the Activity class takes care of creating a window for you in which you can place your UI with setContentView(View).

While activities are often presented to the user as full-screen windows, they can also be used in other ways: as floating windows (via a theme) or embedded inside of another activity (as a dialog).

23. What is a Service?

A Service is an application component that can perform long-running operations in the background and does not provide a user interface. Another application component can start a service and it will continue to run in the background even if the user switches to another application.

Services can also be bound to an activity, meaning that they can communicate with the activity and perform work for the activity while the activity is running.

24. What is a Content Provider?

A ContentProvider manages a specific set of application data and makes it accessible to other applications. It provides mechanisms for defining data security (such as permissions) and for handling concurrent access by multiple applications.

25. What is a Broadcast Receiver?

A BroadcastReceiver is an application component that responds to system-wide broadcast announcements. Many broadcasts originate from the system—for example, a broadcast announcing that the screen has turned off, the battery is low, or a picture was just taken.

Applications can also initiate broadcasts—for example, to let other applications know that some data has been downloaded to the device and is available for them to use. Although broadcasts are normally sent by the system, they can also be sent by applications.

26. What is an Intent?

An intent is an abstract description of an operation to be performed. It can be used with startActivity to launch an Activity, broadcastIntent to send it to any interested BroadcastReceiver components, and startService(Intent) or bindService(Intent, ServiceConnection, int) to communicate with a background Service.

27. What is a Fragment?

A Fragment represents a behavior or a portion of the user interface in an Activity. You can combine multiple fragments in a single activity to build a multi-pane UI and reuse a fragment in multiple activities.

You can think of a fragment as a modular section of an activity, which has its own lifecycle, receives its own input events, and which you can add or remove while the activity is running (sort of like a “sub-activity” that you can reuse in different activities).

28. What are the differences between an Activity and a Service?

An Activity represents a single screen in an app. A Service is a component that runs in the background to perform long-running operations or to perform work for remote processes.

29. What is a Resource?

A resource is a piece of data that can be used by an Android app, such as a string or a bitmap. Resources are stored in the /res directory.

30. What is a Context?

A Context is an object that provides access to resources and services related to the application environment. A Context allows you to access application-specific resources and classes, as well as request and enforce security policies.

31. What is an Intent Filter?

An Intent Filter is an expression in an Android Manifest file that specifies the type of intents that an activity, service, or broadcast receiver can respond to. An intent filter can match against actions, categories, and data (both the type and scheme of data).

32. What is ADB?

Android Debug Bridge (adb) is a versatile command line tool that lets you communicate with an emulator instance or connected Android-powered device. It is a client-server program that includes three components:

• A client, which runs on your development machine. You can invoke a client from a command-line terminal by issuing an adb command. Other Android tools such as the ADT plugin and DDMS also create adb clients.
• A server, which runs as a background process on your development machine. The server manages communication between the client and the adb daemon running on an emulator or device.
• A daemon runs as a background process on each emulator or device.

33. What is AAPT?

Android Asset Packaging Tool (aapt) takes your application resource files, such as the AndroidManifest.xml file and the XML files for your activities, and compiles them into a single .apk file. The .apk file contains all of your application’s code (.dex files), resources, assets, and manifests.

34. What are the 4 essential states of an activity?

The four essential states of activity are:

• Active – The activity is in the foreground and has user focus.
• Paused – The activity is partially obscured by another activity (that is, it’s on top but doesn’t have a focus).
• Stopped – The activity is completely obscured by another activity and isn’t visible to the user. It still retains all state and member information but can be killed by the system in extremely low-memory situations.
• Destroyed – The activity has finished executing and has been removed from memory. It won’t be restarted unless the user explicitly navigates back to it.

35. What are the differences between a regular .apk file and a signed .apk file?

A regular .apk file is an Android package file that hasn’t been signed. A signed .apk file is an Android package file that’s been signed with a digital certificate. When you sign an .apk file, you’re adding your personal signature to the app. This signature identifies you as the author of the app and indicates that you’ve verified that the code in the app has not been tampered with.

36. What is R8?

R8 is a code shrinker and optimizer for Java bytecode. It’s designed to improve the performance and size of your Android apps. R8 can remove unused code and resources, optimize your app’s code for performance, and package your code and resources into a single .apk file.

37. What is ProGuard?

ProGuard is a tool that can help you shrink, optimize, and obfuscate your Java bytecode. ProGuard performs three main tasks:

• It removes unused classes, fields, methods, and attributes from your code.
• It optimizes the bytecode of the remaining classes, fields, and methods.
• It renames the remaining classes, fields, and methods with shortened names.

38. What is Dexguard?

Dexguard is a commercial version of ProGuard that’s designed specifically for Android applications. Dexguard offers additional features, such as string encryption and class member hiding.

39. What is a Gradle?

Gradle is a build tool that’s used to automate the process of building Android applications. Gradle can be used to compile and package your code, run unit tests, and generate signed .apk files for distribution.

40. When is the onStop() method invoked?

The onStop() method is invoked when an activity is no longer visible to the user. This can happen when the activity is being destroyed, or when another activity (such as a dialog) is being displayed on top of it.

41. When is the onDestroy() method invoked?

The onDestroy() method is invoked when an activity is destroyed by the system. This can happen when the user presses the back button, or when the system needs to free up memory.

42. What are some best practices for managing Android app size?

Some best practices for managing Android app size include:

• Use ProGuard or Dexguard to remove unused code and resources from your app.
• Use Android App Bundles to generate smaller .apk files for specific device configurations.
• Use Android Instant Apps to allow users to run your app without installing it.
• Use Google Play’s Dynamic Delivery to deliver only the code and resources that are needed for a specific device configuration.

43. What is an Android App Bundle?

An Android App Bundle is a file that contains all of the compiled code and resources for your app, but can be split into smaller .apk files that are downloaded on demand by the Android system. This allows you to reduce the size of your app for users who don’t need all of its features.

44. What is an Android Instant App?

An Android Instant App is a version of your app that’s designed to run without being installed on the user’s device. Instant Apps are launched by clicking a URL, and they allow users to use your app without installing it.

45. What is Google Play’s Dynamic Delivery?

Google Play’s Dynamic Delivery is a feature that allows you to deliver only the code and resources that are needed for a specific device configuration. This helps you reduce the size of your app for users who don’t need all of its features.

46. How do you manage app signing keys?

App signing keys are used to sign Android applications for distribution. They’re generated by the Android SDK, and they’re stored in a keystore file. The keytool utility is used to manage app signing keys.

47. What are the core components under the Android application architecture?

The Android application architecture has five core components:

• Activities
• Intent
• Resource Externalization
• Notifications
• Content Providers

48. Do all mobile phones support the latest Android operating system?

While some Android phones can be upgraded to a newer operating system version, not all will allow you access to the latest and greatest features. It largely depends on how new or old your phone is as well as its capabilities and specs.

49. Explain the dialog boxes supported on Android.

There are four types of dialog boxes supported on Android:

• AlertDialog: This is used to display an alert message to the user.
• ProgressDialog: This is used to display a progress bar to the user.
• DatePickerDialog: This is used to display a date picker to the user.
• TimePickerDialog: This is used to display a time picker to the user.

50. What is AndroidManifest.xml file and why do you need this?

AndroidManifest.xml is a configuration file that is used to specify the settings for an Android app. It’s required for all Android apps, and it must be located in the root directory of the app’s project.

51. Explain different launch modes in Android.

There are four launch modes in Android:

• Standard: This is the default launch mode. It simply creates a new instance of an activity when it’s started.
• SingleTop: This launch mode is used to create a new instance of an activity if it’s not at the top of the stack. Otherwise, it will reuse the existing instance.
• SingleTask: This launch mode will create a new instance of an activity, but it will also route all future instances of that activity to the existing instance.
• SingleInstance: This is the most restrictive launch mode. It will create a new instance of an activity, and all future instances will be routed to that activity. In addition, only one instance of that activity can exist at a time.

52. Explain the difference between Implicit and Explicit Intent.

An implicit intent is an intent that doesn’t specify a particular component to handle it. An explicit intent is an intent that specifies a particular component to handle it.

53. Is it possible to run Android apps on a PC?

Yes, it’s possible to run Android apps on a PC. There are a few different ways to do it, and the most common is to use an emulator. Emulators allow you to run Android apps on your PC as if it were a physical device.

54. Mention the difference between class, file, and activity in Android?

A class is a blueprint for an object. A file is a container for data. An activity is a component that represents a screen in an app.

55. What do you mean by thread priority in Android?

Thread priority is the importance that a thread is given by the operating system. Higher-priority threads will be given more time to run than lower-priority threads.

Final Thoughts

That’s our roundup of the best interview questions to ask Android developers. These questions will help you hire the best Android engineers for your team.

There are many other great interview questions out there. So do your research and find one that works for you and what you need.

The above 55 questions should give you a good indication of the Android developer’s skill set and experience. If they can answer all of these questions, then they are probably a great fit for your team.

Happy interviewing!