Android Interview Questions and Answers

Statista states Android will have the largest market share among mobile operating systems worldwide in 2024. It shows the operating system's wide use and subsequent job opportunities in many reputed companies worldwide.

In this article, MindMajix offers Android Interview Questions 2024 that help you crack your Android interviews and acquire a dream career as an Android Developer. It includes the questions and answers for all types of learners, including freshers and beginners.

If you're looking for Android Interview Questions for Experienced or Freshers, you are in right place. There are a lot of opportunities from many reputed companies in the world. According to research, Android has a market share of about 0.7%. So, You still have the opportunity to move ahead in your career in Android Development. Mindmajix offers Advanced Android Interview Questions 2024 that help you in cracking your interview & acquire a dream career as Android Developer.

Table of Contents:

• Skills Required for Android Developers
• Job Responsibilities of Android Developers
• Android Developer Interview Questions
  
  • for beginners
  • for intermediate learners
  • for Experienced Learners
• Tips
• Frequently Asked Questions

Top 10 Android Interview Questions

1. What is Android?
2. What is ANR?
3. What is the Android application Architecture?
4. Explain the Android activity lifecycle.
5. How does Garbage Collector work in Android?
6. Explain the different types of Android UI layouts
7. Explain the Android Architecture
8. Explain the Fragment Lifecycle.
9. Explain services in Android.
10. Explain Android Jetpack.

Skills Required for Android Developers:

In this section, we will learn the primary and secondary skills required for Android developers before diving into the Android interview questions and answers.

Primary skills:

• Sound expertise in mobile application development using Java and Kotlin
• Good understanding of Android SDK and various Android versions
• Strong exposure to RESTful APIs and CI/CD integrations
• Familiar with the Android ecosystem and libraries
• Familiar with versioning tools like Git
• Proficiency in Android UI design principles and best practices
• Proficiency in PHP, CSS, HTML, and JavaScript
• Exposure to Moodle APIs and plugin development frameworks

Secondary Skills:

• Knowledge of Google Material design principles
• Familiar with performance profiling tools like Android Studio memory and CPU monitor
• Exposure to agile development methodologies
• Problem-solving and critical thinking
• Excellent communication and collaboration skills

Job Responsibilities of Android developers:

Understanding the job responsibilities of Android developers will be highly useful. It will help you prepare for your interview more accurately.

Beginners:

• Developing high-quality and high-performance mobile applications
• Examining the quality and responsiveness of applications
• Identifying and troubleshooting bugs and bottlenecks in mobile application development and rectifying them
• Enhancing the effectiveness of existing functionalities and features of Android applications
• Writing clear, user-friendly documentation for developers and users

Intermediate-level:

• Reviewing peer codes and guiding them to improve code quality
• Collaborating with other developers, product managers, designers, architects, quality assurance, and backend development teams to deliver high-quality products
• Optimising the performance of applications for multiple devices and screen sizes
• Performing unit testing and integration testing to verify the quality of codes
• Working with Android development tools like profilers, Android Studio, etc., effectively

Expert level:

• Mentoring peer developers and helping them implement best practices that meet the latest industry standards.
• Discovering trending technologies and making efforts to implement suitable technologies in Android development to boost efficiency
• Conducting interviews and identifying talents for teams
• Deeply involved in application deployment and release processes

If you would like to Enrich your career with an Android certified professional, then visit Mindmajix - A Global online training platform: “Android Certification Training” Course. This course will help you to achieve excellence in this domain.

Android Interview Questions and Answers

This section is divided into three sections for beginners, intermediate learners, and experienced users. Based on your Android expertise, you can either jump into the correct section or walk through it individually.

Let’s begin!

Android Interview Questions for Beginners:

 In this section, you will learn the basic Android interview questions, strengthening your foundation on Android OS.

1. What is Android?

Ans: Android is an open-source, Linux-based operating system for developing mobile applications. It has a large ecosystem with excellent customisation options. We can seamlessly integrate Android applications with Google Drive, Google Maps, and other Google products.

Android supports Edge, Bluetooth, multiple 3G communication protocols, messaging, and more. It provides exceptional flexibility and affordability to its users. Above all, Google updates Android OS regularly, improving security and performance.

2. What is the latest version of Android?

Ans: Android 15 (vanilla ice cream) is the latest Android version, released in October 2024.

3. What are the key features of the latest Android version?

Ans: Android 15 is the latest Android version, which has the following key features.

• Incorporated private space for storing highly sensitive data like health and banking
• Improved camera power for tackling challenges in low-light environments
• Enhanced security features such as Play Protect and the Credential Manager. They help to track suspicious behaviours and enable single-tap sign-in
• Added satellite connectivity support, screen recording detection, etc.

4. What is the context of Android

Ans: In its basic form, context in Android is an abstract class that connects an application with the Android system. Context acts as an interface and helps users access application-specific resources like themes, strings, etc.

We can use context to access resources, including colours, drawables, dimensions, etc. We can also start new activities in internal and external applications. The important thing is that to avoid leaks in contexts, we must include a reference to a context only if it is required.

5. What is a Content Provider in Android?

Ans: A content provider is essentially an interface that connects data in one process to code in another process. It helps applications access, share, and modify data securely. It also acts as the central repository where data is stored in different formats, including databases, files, etc.

A content provider serves as a bridge between applications in exchanging data. It provides granular control over accessing data with permissions. For example, it can control which application can access, read and modify data, ensuring security to greater levels.

6. What image-loading libraries are used in Android?

Ans: Jotted down are the different image-loading libraries used in Android.

• Picasso
• Fresco
• Universal Image Loader (UIL)
• Glide
• Coil

7. What is an activity in Android?

Ans: An activity is typically a single screen in an Android application with a user interface. Activities are the core building blocks of Android applications, and each screen has a purpose and interacts with users.

We embrace activities for handling user inputs, displaying information, and responding to events. Every activity has a life cycle: creation, display, pause, and destruction. Examples of activities are a login screen, signup screen, home screen, and more.

8. What is the use of app bundles in Android?

Ans: An Android app bundle is a publishing format containing an Android application's compiled codes. It delays signing in to Google and APK generation, which helps to reduce the application's download size.

App modules allow users to download only the necessary codes and resources for specific devices. They accelerate installations with smaller files and support developing applications that include all code and resources with configurations.

9. Write a calling activity in Android.

Ans: Below is an example of calling activity in Android.

Intent i = newIntent(getApplicationContext(), ActivityTwo.class);
startActivity(i);

10. What is ANR?

Ans: ANR stands for Application Not Responding. Generally, this dialogue pops up in the Android system if an application performs too many tasks. Then, the application becomes unresponsive for quite a long time—to be precise, if it doesn't respond for more than five seconds during the ANR condition.

Android has many types of ANRs, including input ANR, Timeout ANR, Broadcast Receiver ANR, Service ANR, and timeout expired ANR.

11. What is the Android Application Architecture?

Ans: The Android application architecture has many components. It includes:

• Services: It creates the functionalities performed in the background
• Content Providers: It consists of the data shared between the applications
• Resources: It includes strings and graphics
• Notification: It includes notification, sound, light, and dialogue boxes.

12. Define the APK format.

Ans: APK is an abbreviation for the Android Packaging Kit, the file format for applications on the Android OS. An APK file contains the essential information for an application to operate on a device, including details about installing the application and the package.

We can create APK files in Android Studio. The good news is that we can also open APK files on Windows, MacOS, and Android platforms.        

13. What is Intent in Android?

Ans: Intent is a messaging object that enables communication between the components of an Android application. In other words, we can use intent to request an action from another component in an application.

There are three primary uses of intent: starting an activity, starting a service, and delivering a broadcast receiver. For example, we can use intent to call a second activity from a first activity, send data to components, start services, etc.

Related Article: What is Android

14. Are there any specific names of Android versions?

Ans: Yes, there are some specific names for different Android versions.

• Blender
• Astro
• FroYo
• KitKat
• Cupcake
• Gingerbread
• Jelly Bean
• Lollipop

15. Why is Android so popular among developers?

Ans: The prime reason for its popularity is free use. Furthermore, it comes with:

• Open source: No distribution, license, or development charge exists.
• Independent platform: It supports Windows, MacOS, and even Linux-based platforms for user-friendly solutions.
• Technological Support: Android supports Bluetooth, Wi-Fi, Camera, Speech, and Edge.
• Virtual Machine: Android uses a well-optimized virtual machine called the Dalvik Virtual Machine.

16. Is there any language other than Java used in Android?

Ans: We can develop Android applications with C, C++, and Native Development Kit. 

17. List the core building blocks of Android.

Ans: The core building blocks of Android are categorised into:

• View
• Activity
• Service
• Content Provider
• Intent
• Fragment

18. Can you name the different storage methods supported by Android?

Ans: Android supports the following storage methods for storing data. Here we go:

• Internal storage
• SQLite databases
• External storage
• Emulated storage
• Shared preferences
• Adoptable storage
• Portable storage

19. What are the media formats that Android supports?

Ans: Android supports the below media formats.

• AMR-NB
• FLAC
• AMR-WB
• MIDI

20. Which Linux kernel can be used in Android?

Ans: Regarding Android, the Linux 3.6 kernel can be used.

21. Do you know about the Android application Widgets?

Ans: With widgets, we can easily embed small application views in other applications. This will periodically provide us with updates.

22. What are the flag types by which Android Application runs?

Ans: We can categorise flags into two types for running Android Applications:

• Flag_Activity_Clear_Top
• Lag_Activity_New_Task

23. Name the basic tools used to develop an Android app.

Ans: Generally, Android apps can be developed using:

• Eclipse + ADT plugin
• SDK Tools
• JDK

22. What is a system-wide broadcast?

Ans: We adopt system-wide broadcast in Android to alert applications about system-wide events. In its basic form, a system-wide broadcast is a message that Android systems pass to applications with access to receive messages.

Related Article: Services in Android

25. List some of the Android jetpack libraries.

Ans: Below are some of the Jetpack libraries.

• Ads
• Annotation
• Appsearch
• Biometric
• Collection
• ContentPager

26. What is kotlin multiplatform?

Ans: The Kotlin platform helps simplify the development of cross-platform projects. It significantly reduces code writing and allows the same code to be used on different platforms.

We can also develop mobile applications in Android Studio and use them on the iOS platform. It works because the iOS platform has a shared data access layer with Android.

27. What is Kotlin flow on Android?

Ans: Kotlin flows are types built on top of coroutines that deliver multiple values sequentially. In other words, flows are data streams we can compute asynchronously.

For example, we can use Kotlin flows to receive live updates from a database and make network requests to produce the next value without blocking the main thread.

Cheers! You have learned the basics of Android and are now ready to learn the advanced concepts.

Android interview questions and answers for Intermediate: 

In this section, you will jump into the Android QA covering advanced Android concepts.

28. Explain the Android activity lifecycle.

Ans: Seven methods control this type of lifecycle. Android Activity's prime focus is creating a subclass of the ContextThemeWrapper class.

The Android activity consists of:

• onCreate( ): This callback is fired after the system creates the activity. In this method, we can create the application start-up logic.
• onStart( ): The system invokes this callback soon after the activity enters the started state.
• onResume( ): The system enables this callback once the activity enters the resumed state. In this state, the application interacts with the user.
• onPause( ): The system invokes this callback when the user leaves the activity. The activity will be visible but not in use.
• onStop( ): The system enables this callback when the activity is no longer visible to the user. Now, it enters the stopped state.
• onDestroy( ): We can call This method before the activity is destroyed. It happens because of two reasons. One reason is when the activity is finished. Another reason is when the system is destroying the activity because of configuration changes. They can be used in device rotation or multi-window mode.
• onRestart( ): The system invokes this state when the activity returns to interact with the user.

29. Where will you declare an activity on Android to ensure a system gets access? 

Ans: We must declare the activity in the AndroidManifest.xml file in the project to ensure that the system gets access to it. The manifest file is the central configuration file where we declare activities, properties, services, and content providers.

Android: name, Android: label, and Android: exported are the essential attributes we use to declare activities in the manifest file. Android: name specifies the class name of activities. Android: label provides the label for the activity. Finally, Android: exported is a control that we use to control external applications using the activity.

30. What are the differences between activities and services?

Ans: 

Activities	Services
They are interactive and user-facing.	They are non-interactive and run in the background.
We can use activities only when there is continuous user input through UI.	We can use services even though there is no interaction with UI.
The login screen and galley viewer are some examples of activities. They need continuous user inputs to continue.	Playing audio is an example of a service because users can use another app while playing audio.

31. Why can standard Java bytecode run on Android?

Ans: Android uses the Dalvik Virtual Machine platform. It certainly needs a bytecode for smooth functioning. To ensure all files are converted into Dalvik executable files, we need to convert Java class files into Dalvik. It can be done with the help of a tool known as 'dx'.

32. Explain the differences between implicit intent and explicit intent.

Ans: 

Implicit Intent	Explicit intent
It doesn't specify a component name. Although it defines a general action, the system should find a component to manage the intent.	It specifies the component to be launched within an application.
For example, if we want to open a browser for a task, we don’t need to mention anything. The system will open a suitable browser relevant to the task.	For example, we can use explicit intent while navigating between activities in the same application.
It is highly flexible since it allows systems to select components.	It is less flexible as we need to specify the target component.

33. Can you describe the action present on Android?

Ans: A description of the sender's intent requires action. It is included in syntax and comes with a description where the action is added to an intent filter. 

34. Can we make two Android applications with the same ID as Linux for sharing?

Ans: The application must sign with the same certificate to ensure it shares the same user ID and Virtual Machine. It wil provide accurate results.

35. Can you perform JAR deployments on Android?

Ans: There is no way since the Android platform cannot effectively support JAR deployments. Applications packed in the Android Package are deployed for the Android platform with the help of Android Asset Packaging software.

36. Could you name the resource that compiles the visual resource and which you can use as a background, title, and in other screen parts?

Ans: A virtual resource called Drawable is used for different purposes, such as background, title, and other screen parts. 

We must store the bitmaps for some resolutions in the Drawable subfolders. If such bitmaps are offered in other folders, the Android system will select the right option depending on the device's configuration.

37. What is the crucial difference between file, class and activity in Android?

Ans:

• File: A file is a physical entity that stores data in storage devices. Android supports resources, source code, manifest, and build files. In Android, files represent XML files that provide the screen design.
• Activity: A specific class type represents a single screen with a user interface. It handles user interactions and UI elements.
• Class: It is a blueprint for creating objects and defining their properties and behaviours. It is a user-defined data type compiled from Java files, helping to generate executable APKs.

38. Why is XML used for frontend development in Android?

Ans: Here are the reasons why XML is used for frontend development in Android.

• XML separates presenting applications from their codes. In other words, it separates UI design from the application logic.
• It provides different UI layouts for different screen sizes
• It helps to manage various resources, including colours, strings, styles and dimensions.
• It exchanges data in a standardised human-readable format, so it is a go-to choice for Android developers
• It provides a declarative syntax, which simplifies defining UI components.

39. How does Garbage Collector work in Android?

Ans: The garbage collector in Android frees unused objects from storage and allocates memory for further use. It is triggered when memory is scarce, or the heap size reaches its limit.

The garbage collector uses the mark-sweep algorithm to identify the objects that are no longer in use. There are two phases in the garbage collection: mark and sweep. The Garbage collection starts at the mark phase by marking every object it visits. In the sweep phase, the unused objects are removed collectively.

Related Article: Android Installation

40. How do you improve RecyclerView scrolling performance in Android?

Ans: The following are the different ways we can optimise RecyclerView scrolling performance in Android.

• Using image-loading libraries like Fresco, Glide, etc.
• Using the onBindViewHolder method to the least
• Setting the correct image width and height
• Using the notify item RecyclerView API
• Avoiding nested views and creating flat views.

41. What is the difference between onCreate() and onStart()?

Ans. 

onCreate()	onStart()
It is called when an activity is created	It is called when an activity is visible to users
It is called when there is a screen rotation or system memory reclamation.	It is called when an activity enters the started state.
It is responsible for initialising essential components, including layout inflation, retrieving references to UI elements, etc.	It initiates animations, play sounds and other visual or auditory cues.
It supports setting up event listeners and performing other initialisation tasks.	It supports registering broadcast receivers, UI animations, and acquiring system resources.

42. Could you explain a singleton class in detail?

Ans. Singleton is essentially a design pattern we use in Android applications to create an item for once. In simple words, a singleton class has only one instance.

The important thing is that other classes and subclasses cannot create instances. A singleton class is globally accessible, so every class can use the singleton class instance.

There are a lot of advantages to using the singleton classes.

• efficient resource management
• easy coordination of actions
• centralised configuration
• centralised logging and debugging services
• efficient caching mechanisms

43. What are the essential methods of a content provider?

Ans. Below are the essential methods of a content provider.

• query(): This method receives requests from clients. We will receive the request as a cursor object.
• oncreate(): This method is called when the provider is started
• insert(): It helps to insert a new record into the content provider
• update(): It updates the existing records in the content provider
• delete(): It deletes the records from the content provider

44. Explain the different types of Android UI layouts.

Ans. Let’s discuss the different Android UI layouts.

• Android Linear Layout: We can use a ViewGroup subclass to provide child view elements in a two-way direction.
• Android Constraint Layout: This layout allows us to specify the position of layout constraints for every child view.
• Android Relative Layout: It is another ViewGroup subclass that we use to specify the position of child view elements relative to their parent
• Android Frame Layout: This layout specifies a single object on a screen. We host it to host a single-child view. You can add many child elements to a frame layout.

45. Discuss the advantages of using Kotlin for Android development.

Here are the advantages of using Kotlin for Android development.

• Kotlin codes are concise. We can minimise the number of code lines dramatically.
• It is highly suitable for developing large and complex application developments.
• It provides clean syntax and easily readable codes
• It avoids common errors. It supports writing high-quality codes and boosts productivity
• It supports Java interoperability. It means we can mix Kotlin and Java codes without harming application performance.
• Developers can build native Android applications using Kotlin quickly

46. Explain Kotlin coroutines:

Ans. A coroutine is a concurrent design pattern that simplifies asynchronous code execution. We use coroutines widely in Android development because they break down long-running tasks into simple ones.

Coroutines help avoid blocking the execution of the main thread and prevent your application from becoming unresponsive. Therefore, developers extensively use coroutines in app development to improve productivity.

47. How do you build CI/CD pipelines in Android using Github?

Ans. We must follow the steps below to build CI/CD pipelines in Android.

• First, open the Android Studio
• Change the app file structure to project mode
• Create a new directory with the name .github/workflows
• Finally, create a new file inside the workflow folder with the name androidbuild.yml

48. How can you perform dependency injection in Android using hilt?

Ans. Hilt is a dependency injection library that significantly reduces manual dependency injection by providing containers for every class.

Moreover, hilt provides compile-time correctness, runtime performance, scalability and more.

Congrats! Now that you have gained expertise in Android concepts, it's time to explore its deeper dimensions.

Android interview questions and answers for Experienced:

In this section, you will travel through the crucial QA that will provide you with a holistic knowledge of the Android platform.

49. Explain the Android Architecture:

Ans. The key components of Android architecture include the following:

• Linux Kernel: The Linux kernel is the foundation of the Android platform. Android Runtime depends on it for threading and low-level memory management.
• Hardware Abstraction Layer (HAL): HAL provides interfaces that connect hardware capabilities to the higher-level Java API framework. It consists of multiple library modules, including camera and Bluetooth modules.
• Android Runtime: Android Runtime, or ART, supports running multiple virtual machines on low-memory devices. It executes DEX files, a bytecode format designed for Android OS. AOT and JIT compilation, garbage collection, and debugging support are the key features of Android runtime.
• Native C/C++ libraries: ARL and HAL are some Android components built using native libraries written in C/C++ language. We can access the OpenGL ES library using the Java OpenGL API and the Android API.
• Java API Framework: We can utilise the features of the Android operating system using APIs written in Java. The APIs are the building blocks for constructing Android applications. They allow the reuse of system components and services. The components include a view system, notification manager, resource manager, activity manager, and content providers.
• System Applications: Android has core email, calendars, SMS, contacts, and more applications. The applications are helpful for both developers and users.

50. Explain the Android manifest file.

Ans: Every application project must include the Android manifest file. This file provides the necessary information about the application to Android build tools, the operating system, and Google Play.

The manifest file is required to declare the application components, permissions and the hardware /software features.

• Application Components: Every app component we create in an Android application declares an XML element in the manifest file. For example, the components are service, activity, receiver, and provider, and the corresponding XML elements are service, activity, Broadcast Receiver, and Content Provider.
• Permissions: Android applications must ask permission to access sensitive user data, including cameras, contacts, SMS, etc. Permissions are identified with unique labels in manifest files.
• Intent filters: An intent is typically a message defined by an intent object. All the application activities, services and broadcast receivers are enabled by intent.
• Device Compatibility: We use many manifest tags to ensure device compatibility, including uses-feature and uses-sdk. The uses-feature tag helps to declare hardware and software features that an application needs. The uses-sdk tag supports the minimum version of a device compatible with an application.

51. Explain the important files and folders when creating a new Android application.

Ans: We need to store the crucial files and folders in the app directory. These include the androidmanifest.xml file, build.gradle files, the res folder for resources, the tests folder, and the Java folder for our source code.

• Androidmanifest.xml file: It is the configuration file that includes the activities, app components, permissions, application name and icon, etc.
• Java folder: It consists of the Java codes for the application logic. It includes activities, fragments, services, and broadcast receivers.
• Res Folder: This folder contains the images, strings, layouts, colours, and styles. Its subfolders include layout, mipmap, drawable, and values. Resources are organised logically in this folder.  

52. Explain Java classes associated with the use of sensors on Android.

Ans. Sensor, SensorManager, SensorEvent, and SensorEventListener are the key Java classes related to android sensors.

• Sensor: This class establishes an instance of a specific sensor and provides many methods for assessing its capabilities.
• SensorManager: This class can create a sensor instance. It provides many methods for accessing sensors, registering sensor event listeners, etc. It also has many sensor constants that we can use to mark sensor accuracy and calibrate sensors.
• SensorEvent: This class helps create a sensor event object. Every sensor event object includes the raw sensor data, data accuracy, the sensor type, and the event's timestamp.
• SensorEventListener: We call this class to receive messages from the SensorManager. This message is sent while there is new sensor data,

53. Explain the Fragment Lifecycle.

Ans. In Android, we use fragments to create dynamic user interfaces. The good thing about the fragment is that it simplifies building UIs for multiple screen sizes.

Every fragment has a lifecycle, including the methods below.

• onattach ( ): This method is called by the system even before the onCreate () method is called. It ensures that a fragment is attached to an activity.
• onCreateView( ): This method is called when the fragment is ready to draw its UI for the first time
• OnViewCreated (): The system uses this method to inherit the on-create view () implementation. It helps configure the resulting views.
• OnactivityCreated ( ): This method shows that the creation of an activity is over.
• onStart( ): This method is called when the fragment is visible to users.
• onPause( ): When a user leaves the fragment, the system calls this method.
• onStop( ): This method is called to stop the fragment.
• onDestroyView( ): It is called before destroying the fragment.
• onDestroy(): This method is called to clean up the fragment’s state
• onDetach(): This method is called to notify that the fragment has been detached from its hosting activity.

54. Why must you call setContentView() in onCreate()?

Ans. Generally, setContentView() is a heavy operation. We call setContentView() in onCreate() since we can call an activity's onCreate () only once. It is not advisable to call Setcontentview() in onResume() and onStart() because they are called multiple times.

55. How do you build a single RecyclerView with multiple view types?

Ans. Following is the step-by-step approach to creating a RecyclerView with multiple view types.

• First, create a new project in Android Studio
• Then, add dependencies to implement recyclerview in activity_main.xml
• Add the required drawable file in the resource directory.
• Create all the item layouts
• Create an item class and the adapter class
• Finally, complete the mainactivity.java file

56. How do you manage different screen sizes in Android?

Ans. Below are the methods that help to handle different screen sizes in Android.

• Using the ‘wrap-content’ and ‘match-parent’
• Using Relativelayout
• Using the small-width qualifier
• Using the orientation qualifiers
• Using size qualifiers
• Using the layout aliases
• Using the nine-patch bitmaps

57. How do you create a custom view in Android?

Ans. Below is the step-by-step procedure to build a custom view in Android.

• First, set up the project
• Create the custom view class
• Integrate the custom view into the XML layout
• Finally, perform testing 

58. How do you implement animations in Android UI development?

Ans. We can implement animations in Android UI development in three ways as follows:

• Using the transition Framework
• Using the MotionLayout
• Using the AnimationDrawable

59. Could you explain the three key loops to help you monitor the activity?

Ans. Each activity is tracked down in Android. It helps in mentoring the activity. It is categorised into three things. They are:

• Visible lifetime: This is an activity taking place between onStop and onStart
• Foreground lifetime: This is an activity taking place between onPause and onResume
• Entire lifetime: This is an activity taking place between onCreate and onDestroy 

60. Could you explain the dialogue boxes that can be used in the Android Application?

Ans. A dialogue box consists of some of the parts such as:

• DatePickerDialog: we use this dialogue for date selection
• ProgressDialog: It is essentially an extension with which we might want to have some buttons. It describes the progress bar.
• AlertDialog: This alertdialog contains three buttons with a selectable elements list
• TimePickerDialog: We use this dialogue to select the time.

61. Can you change the application name once it gets deployed?

Ans. An application's name should be the same once it is deployed. It will break certain functions, and there is a huge risk involved. Supposedly, there will be no shortcuts that would work if we change the name applications of t. Of course, it is possible to change, but once the name is deployed, changing it makes no sense due to the huge loss risk.

62. How can you prevent ANR?

Ans. Let’s see the causes of the occurrence of ANR and the ways to fix them.

• Keeping the main thread unblocked and using threads strategically
• Avoiding long-running operations on the main thread of applications
• Minimising lock contention between the main thread and other threads
• Avoiding sharing the same threads for time-sensitive tasks
• Applying canvas drawing methods efficiently
• Leveraging strict mode to identify unintentional I/O operations on the main thread.

63. Explain services in Android.

Ans. In Android, there are two types of services: started and bound services. Let's examine them.

• Started services: When an application calls the startservice () method, the service is declared started. We can stop this service using the stopservice() and stopself() methods.
  • Once started, a started service runs in the background. It runs continuously even though the component that created the service has been destroyed.
  • Start services are also called as background services. They become active when application components call the Startservice() method. The application components can be the receiver, activity,  or provider.
  • It performs a single operation and doesn’t return any result.
• Bound Services: A service is known to be bound when an application component binds using the bindservice() method.
  • It returns results to callers
  • It continuously interacts with the element that is called it
• Started Services:
  • OnCreate(): It is called when the service is created
  • OnStartcommand(): It is called when the component uses the Startservice() to start the service
  • OnDestroy(): It is called when the service is no longer required and to destroy the service
• Bound Services
  • OnCreate(): It is called when the service is created
  • OnBind(): This is when the component binds to the service. In this case, the components use the bind service () method.
  • OnUnbind(): It is called when clients unbind from the service
  • OnDestroy(): It is called when the service is no longer used and needs to be destroyed.

64. Explain about ContentResolvers.

Ans. ContentResolver is essentially a class that allows applications to access content providers. In other words, it is an interface that provides various methods for applications to fetch, interact with, and edit content stored in applications, file systems, and APIs.

ContentResolver acts as a client that communicates with content providers to support data operations. It receives requests to access content providers and resolves them with full authority.

Like abstract methods such as insert, update, query, and delete used in content providers, we can apply the CRUD methods such as create, read, update and delete with ContentResolver.

65. Explain Android Jetpack.

Ans. Android Jetpack is a bundle of software components that includes tools, libraries, and more. We can leverage Android Jetpack to build robust Android applications.

Android jetpack has many vital components, including room, work manager, navigation, paging, lifecycle, ViewModel, live data, and more. Let's outline them in the following.

• Room: It helps to reduce boilerplate codes and simplify the database access mechanism
• WorkManager: It provides backward compatibility. It supports scheduling and chaining of tasks.
• Lifecycle: It supports creating organised application components. It also helps to maintain and test components.
• Livedata: It helps to remove stopped and destroyed activities so we can avoid software crashes
• ViewModel: It stabilizes data management while making configuration changes. It helps to reduce UI bugs and crashes.
• Navigation: It supports transition through animated visualisation and deep linking.
• Paging: It helps integrate with the recycler view to display a high volume of data.

66. Explain Jetpack Compose:

Ans. Jetpack Compose is a modern toolkit for Android developers to build native UI applications. This toolkit provides robust development tools, supports fewer codes, and offers Kotlin APIs.

Since Jetpack Compose supports fewer codes, we can easily avoid bugs and maintain codebases. It allows seeing live previews and supports Android Studio. Moreover, it provides built-in support for material design, dark themes, and animations.

67. How will you optimise Android application performance?

Ans. We can optimise Android app performance in the following ways.

• Reducing the app sizes
• loading the data necessary to start apps, increasing the speed
• Optimising layouts using data binding and view binding
• Minimising network requests using libraries such as Picasso and glide
• Eliminating memory leaks using Android profiler and LeakCanary
• Optimising the efficiency of codes using StringBuilders and Asynchronous programming

68. Explain retrofit in Android.

Ans. Retrofit is a networking library for managing network requests in applications. It is a type-safe networking and annotation-based library with simple syntax and better functionalities.

Advantages:

• Retrofit supports request cancellation
• It supports direct communication with web services
• It supports converters and dynamic URLs

Disadvantages:

• It doesn’t have any retry policy
• It doesn’t have a request prioritisation inbuild
• It doesn’t support image loading

Celebrate! You have thoroughly learned the Android interview questions. Now, you can face your Android interviews and confidently bag your dream job.

Tips to crack Android interviews:

Enriching your technical expertise plays a significant role in clearing your Android interviews. But that's not enough. The pointers below will help you crack the interviews on the first attempt.

• Research the company: Before appearing for interviews, thoroughly research the company where you will attend interviews. Study the technologies the company adopts, the products it offers, its clients and business partners, and so on. It will help to impress the interviewers that you are highly interested in the company.
• Prepare a strong portfolio: Ensure your portfolio is robust and includes all the relevant skills and knowledge. Add your projects, interns' details, certifications, workshops, and other information. It will help you show your strengths to recruiters in the best way.
• Attend mock interviews: Don't miss the opportunity to attend mock interviews. They help boost your confidence and examine your competency before appearing for interviews. Final round AI, Pramp, and interviewing.io are some mock interview platforms.
• Be sharp and bold in interviews: Deliver short and sharp answers. Don't exaggerate answers, but at the same time, don't miss anything. Answer relevant to the questions. Don't deviate from the actual answers. You can quote examples and past project experiences wherever needed.

Yes! If you apply these tips, your Android interview will be a breeze. You will crack your interviews on the first attempt.

Frequently Asked Questions:

1. What is the history of the Android operating system?

Ans. Rich Miner, Chris White, Nick Sears, and Andy Rubin established Android Inc. in 2003. Google acquired the company in 2005. It released the first Android phone in 2008.

2. What is the use of Android?

Ans. 

• Android development tools like Android SDK, JDK, and Eclipse IDE are open-source, so their cost is low.
• Android applications support multiple platforms like macOS, Windows and Linux.
• Most telecom carriers, like Airtel, Vodafone, BSNL, etc., support Android-powered phones.

3. Which one is the best operating system – Android or iOS?

Ans. Both Android and iOS have their pros and cons. Android excels in customisation, low cost, user-friendliness, cross-platform support, and other features. On the other hand, iOS excels in security, performance, quick app development, and other features.

4. What is the definition of Android?

Ans. Android symbolises a robot that looks like a human without emotions and feelings.

5. Is Android hard to learn?

Ans. No, learning Android is easy. MindMajix offers job-oriented Android training by industry-experienced trainers for beginners and experienced learners. The training will provide you with the necessary skills to become a competent Android developer in your workplace.

6. How long does it take to learn Android development?

Ans. MindMajix offers a 25-hour-long Android course by trainers with vast Android development experience. The training is delivered in instructor-led live classes and self-paced on-demand videos. You can choose the learning path based on your needs and convenience. So, you can master Android development in 25 hours by choosing MindMajix as your learning partner.

Conclusion:

We hope that the Android interview questions and answers included in this section have provided you with a comprehensive knowledge of Android. The information about skills requirements, job responsibilities, and tips to crack android interviews might have been helpful to you.

Professional training will enhance your knowledge of Android and mobile development. MindMajix offers job-oriented Android training for both beginners and experienced learners. Once you complete the training, you will breeze through your Android interviews and bag your dream job for competitive salaries.