Android is a software package and linux based operating system for mobile devices such as tablet computers and smartphones.
In this blog post, we present 60 multiple choice questions to test your knowledge of Android. Each question has 4 options, a correct answer, and an explanation.
1. What is Android?
Answer:
Explanation:
Android is a mobile operating system developed by Google, designed primarily for touchscreen mobile devices such as smartphones and tablets.
2. Who initially developed Android?
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Android was initially developed by Android Inc., which Google bought in 2005.
3. What is the name of the Android build tool for compiling and packaging apps?
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Gradle is the official build tool for Android, used for compiling and packaging apps.
4. What programming language is primarily used for Android app development?
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Java is the primary programming language used for developing Android apps, although Kotlin is also officially supported.
5. What is an APK in Android?
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APK stands for Android Package Kit. It is the file format used by the Android operating system for the distribution and installation of mobile apps.
6. What does the Android Runtime (ART) do?
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The Android Runtime (ART) is the application runtime environment used by the Android operating system. It converts app bytecode into machine code during app installation.
7. What is the name of Android's virtual machine?
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The Dalvik virtual machine is an integral part of older Android versions, optimized for systems that are constrained in terms of memory and processor speed.
8. Which file specifies the essential features of an Android app?
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AndroidManifest.xml is a file that specifies essential information about the app to the Android build tools, the Android operating system, and Google Play.
9. What is a Content Provider in Android?
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A Content Provider in Android is a component that manages access to a central repository of data, allowing apps to store and retrieve data and share it with other apps.
10. What is an Intent in Android?
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In Android, an Intent is a messaging object you can use to request an action from another app component.
11. What is Android Jetpack?
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Android Jetpack is a suite of libraries, tools, and architectural guidance to help make it quick and easy to build great Android apps.
12. What is the primary language developed by Google for Android app development?
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Kotlin is a statically typed programming language developed by Google specifically for modern multiplatform applications, including Android app development.
13. Which component in Android is responsible for screen navigation?
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Explanation:
An Activity in Android is a component that provides a screen with which users can interact to do something, such as dial the phone, take a photo, send an email, or view a map.
14. What is a Fragment in Android?
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A Fragment represents a behavior or a portion of user interface in an Activity. You can combine multiple fragments in a single activity to build a multi-pane UI.
15. What does ADB stand for in Android development?
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Android Debug Bridge (ADB) is a versatile command-line tool that lets you communicate with a device. It facilitates a variety of device actions, like installing and debugging apps.
16. What is a RecyclerView in Android?
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RecyclerView is a more advanced and flexible version of ListView. It is a container for displaying large data sets that can be scrolled very efficiently by maintaining a limited number of views.
17. What is the Google Play Store?
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The Google Play Store is Google's official store and portal for Android apps, games, and other content for your Android-powered phone, tablet, or Android TV device.
18. What is a Service in Android?
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A Service is an application component that can perform long-running operations in the background and does not provide a user interface.
19. What does XML stand for and how is it used in Android?
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XML, or eXtensible Markup Language, is a markup language used for encoding documents in a format that is both human-readable and machine-readable. In Android, it's primarily used for designing user interfaces.
20. What is Gradle in the context of Android?
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Explanation:
Gradle is an open-source build automation tool that is designed to be flexible enough to build almost any type of software. In Android, Gradle is used to compile and package apps.
21. What is a Toast in Android?
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A Toast provides simple feedback about an operation in a small popup. It only fills the amount of space required for the message and the user's current interaction remains visible and interactive.
22. What is an AsyncTask in Android?
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AsyncTask is designed for short tasks that need to be performed on the background thread and update the UI on the main thread, but it's deprecated in Android API level 30.
23. What is the Android operating system based on?
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The Android operating system is based on a modified version of the Linux kernel and other open-source software.
24. What is ProGuard used for in Android?
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ProGuard is a tool used in Android for app obfuscation, which helps in reducing the APK size and protecting the app code against reverse engineering.
25. What is a Broadcast Receiver in Android?
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A Broadcast Receiver is an Android component that allows you to register for system or application events. All registered receivers for an event are notified by the Android runtime once this event happens.
26. What is DDMS in the context of Android?
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The Dalvik Debug Monitor Server (DDMS) is a debugging tool in Android that provides a wide range of debugging features including port forwarding, screen capture, and memory usage monitoring.
27. What is the primary function of the 'onCreate()' method in Android?
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Explanation:
The 'onCreate()' method is one of the most fundamental lifecycle methods in Android, used to perform basic application startup logic that should happen only once for the entire life of the activity.
28. What is 'Firebase' in the context of Android?
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Firebase is a platform developed by Google for creating mobile and web applications. It provides tools for tracking analytics, reporting and fixing app crashes, creating marketing and product experiment.
29. What is a ConstraintLayout in Android?
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ConstraintLayout is a ViewGroup which allows you to position and size widgets in a flexible way. It allows creating large and complex layouts with a flat view hierarchy.
30. What is a View in Android?
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In Android, a View is the basic building block for UI components. A View occupies a rectangular area on the screen and is responsible for drawing and event handling.
31. What is the use of the 'findViewById' method in Android?
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The 'findViewById' method is used to find and reference views in your activity layout. It returns a view object, allowing you to interact with and modify those views.
32. What is 'SQLite' in Android?
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SQLite is a lightweight SQL database that stores data to a text file on a device. Android comes in with built-in SQLite database implementation.
33. What is the 'Android NDK' used for?
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The Android Native Development Kit (NDK) is a toolset that allows you to implement parts of your app using native-code languages such as C and C++.
34. What is the purpose of 'Google Material Design' in Android?
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Google's Material Design is a design language that combines the classic principles of successful design along with innovation and technology.
35. What is an ANR in Android?
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Explanation:
ANR (Application Not Responding) is a dialog that appears to the user when an application has been unresponsive for a long period of time, usually due to long computations on the main thread.
36. What is 'Doze Mode' in Android?
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Explanation:
Doze Mode is a power-saving feature introduced in Android 6.0 (Marshmallow), which defers background CPU and network activities when the device is unused for long periods of time.
37. What does 'UI Thread' refer to in Android?
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Explanation:
The UI Thread, also known as the main thread, is where user interface operations are performed. It's important not to block this thread to prevent ANR dialogs from showing up.
38. What is the 'Google Assistant' in the context of Android?
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Explanation:
Google Assistant is an artificial intelligence-powered virtual assistant developed by Google, primarily available on mobile and smart home devices, capable of voice interaction and more.
39. What is the function of 'onPause()' in Android app lifecycle?
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The 'onPause()' method is called when the user partially covers the activity (a new, semi-transparent activity such as a dialog starts).
40. What is 'Google Play Services' in Android?
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Google Play Services is a background service that provides core functionality like authentication to your Google services, synchronized contacts, and access to all the latest user privacy settings.
41. What is 'OpenGL ES' in Android?
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OpenGL ES (OpenGL for Embedded Systems) is a subset of the OpenGL 3D graphics API designed for embedded devices such as mobile phones, tablets, and game consoles.
42. What is the purpose of the 'manifest' file in an Android application?
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Explanation:
The manifest file (AndroidManifest.xml) is essential in every Android application. It declares the app's components, permissions, minimum level of API and other essential information.
43. What are 'Shared Preferences' in Android?
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Shared Preferences in Android is a mechanism to store and retrieve key-value pairs of primitive data types, typically used to store user preferences.
44. What is the main purpose of the 'LayoutInflater' in Android?
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LayoutInflater is used in Android to instantiate the contents of layout XML files into their corresponding View objects.
45. What is 'Google Cloud Messaging' (GCM) in Android?
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Explanation:
Google Cloud Messaging (GCM) was a mobile notification service that enabled third-party application developers to send notification data or information from developer-run servers to applications that target the Google Android Operating System.
46. What is a 'Handler' in Android?
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A Handler in Android allows you to send and process Message and Runnable objects associated with a thread's MessageQueue.
47. What is 'Dagger 2' in Android?
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Dagger 2 is a fully static, compile-time dependency injection framework for both Java and Android. It is the evolution of the popular Dagger 1 and is based on the use of Java annotations.
48. What is 'Retrofit' in Android?
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Explanation:
Retrofit is a type-safe HTTP client for Android and Java developed by Square. It makes it easier to consume RESTful web services.
49. What does the 'onDestroy()' method do in Android?
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Explanation:
The 'onDestroy()' method is called by the Android system when the activity is being destroyed. This method is used to perform final cleanup of the activity's resources.
50. What is 'Espresso' in the context of Android?
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Explanation:
Espresso is a testing framework for Android to write concise, reliable, and automated UI tests.
51. What is the purpose of 'LiveData' in Android?
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LiveData is a data holder class that can be observed within a given lifecycle. This means that an Observer can be added to a LiveData object to receive updates on data changes.
52. What is 'Room' in Android?
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Room is part of the Android Jetpack and provides an abstraction layer over SQLite to allow for more robust database access while harnessing the full power of SQLite.
53. What does 'MVP' stand for in the context of Android app architecture?
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MVP stands for Model-View-Presenter. It's an architectural pattern used for developing Android apps, helping to separate the presentation layer from the logic.
54. What is 'Data Binding' in Android?
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Explanation:
Data Binding is a support library that allows you to bind UI components in your layouts to data sources, using a declarative format rather than programmatically.
55. What is 'ViewModel' in Android?
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Explanation:
ViewModel is a class that's responsible for preparing and managing the data for an Activity or a Fragment. It also handles the communication of the Activity / Fragment with the rest of the application.
56. What is 'MotionLayout' in Android?
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MotionLayout is a subclass of ConstraintLayout for Android, allowing developers to animate widgets and manage motion and widget animation in their apps.
57. What is 'Proximity Sensor' in Android?
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A Proximity Sensor in Android detects how close the phone is to an outside object, such as your ear. This is commonly used to turn off the screen during calls.
58. What is 'Picasso' in Android?
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Explanation:
Picasso is a popular open-source Android library for handling image loading and caching, making it easier to display images from external locations in your app.
59. What is 'AAPT' in Android development?
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Explanation:
AAPT (Android Asset Packaging Tool) is a build tool that Android uses to convert your app resource files into a binary format that is optimized for the Android platform.
60. What is 'OkHttp' in Android?
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Explanation:
OkHttp is an open-source project designed to be an efficient HTTP client. It supports HTTP/2, allows network operations to be done outside of the main thread, and includes features like connection pooling.
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