In this article I am going to discuss some basic questions regarding Android development. These questions are frequently asked in job interviews and also cover the main and important topics in Android development. So, now lets discuss the most common Android Developer Interview Questions and their answers. At first we will have a look at some of the Android basic questions.
Android Developer Interview Questions
1) What is Android?
Android is an operating system used on mobile devices and tablets. It is an open source operating system. Android is a Linux kernel-based system with a variety of features. Android developers create applications that run on mobile devices and tablets. These apps have both basic and advanced features.
2) What is SDK in Android?
It stands for ‘Software Development Kit’. For developing an Android application the developers need some development tools. It contains debugging and development tools in a single installable called SDK.
3) What is the Android ADB?
‘Android Debug Bridge’ is a command-line tool and is used to communicate with the device (smart phone, tablet etc.). Hence, ADB is responsible for many device actions like installing an app or debugging.
4) What does ANR mean? Why does it happen?
In Android ANR means ‘Application Not Responding’. It happens when an activity starts running a heavy task in the main UI thread. Usually when a user is interacting with the activity and the activity is in onResume() method then a dialog appears and displays the message ‘application not responding’.
5) Explain the difference between Mobile Application Testing and Mobile Testing?
Mobile application testing includes the testing of different features and functions of applications on a mobile device.
But, Mobile testing itself is the testing of actual mobile device and its related functionalities such as Call, Messaging, Bluetooth etc.
6) Briefly describe the advantages of Android Operating System?
There are lots of advantages of using Android Operating System because Android is platform independent operating system. It supports removable battery and storage, also it has technologies like Wifi, Infrared and Bluetooth.
7) Explain Android Architecture?
Android architecture consists of the following components
1- The Linux Kernel
2- Hardware Abstraction Layer (HAL)
3- Android Runtime
4- Application Framework (Java API Framework)
8) What are the 4 types of app components in Android?
The 4 main components in Android are:
3- Content Providers
4- Broadcast Receivers
9) Define AAPT?
AAPT also known as ‘Android Asset Packaging Tool’. It is available in the SDK inside the tools/ directory. With the help of this tool one can create, view or update Zip archives. Also, it compiles resources into binary assets.
10) What is Manifest file in Android?
Android Manifest.xml file is a file that every Android application must have in its root directory. Because, it gives the necessary details about the application to the Android System. So, before running the app Android System reads the necessary information about the application from Manifest.xml file.
11) What is an Activity?
12) What is an Intent in Android?
Intents are the means of communication between the components of Android Applications. It passes messages between components such as activities, services, content providers etc. It is also used to pass data between activities. Generally startActivity() method is used to start another activity using Intents.
13) What is Content Provider in Android?
Content Providers in Android is a mechanism which allows to access the data of other applications. Such as the data stored in the databases. So, without the help of Content Providers it would be really difficult to access the data of other Android applications.
14) What is Service in Android?
Service in Android is a component that runs in the background to run long-running operations. It does not need to interact with the user and it still works when the application is closed or the activity is destroyed.
15) What is a Broadcast Receiver?
It is an Android component which allows to register events within Android system or Applications. Then, all the registered events are notified by the System at runtime when a particular event happens. So, Broadcast Receiver is responsible for notifying all these events when they occur.
16) What is a fragment?
A fragment is a representation or a behavior of a portion of UI. So, Fragment has its own XML Layout and Java/Kotlin class. Also, we can use multiple fragments in a single screen. A fragment has its own lifecycle but it totally depends upon the lifecycle of the activity hosting the Fragment.
17) Explain the Android Activity Lifecycle?
When a user interacts with an application and browse different features of the application then the states of the application also change according to the interaction of user with the activity.
Because these states include in Android Activity Lifecycle they are, onCreate(), onStart(), onRestart(), onResume(), onPause(), onStop(), and onDestroy(). These called ‘ callback functions’.
These methods are called when the activity is created or starts or when the user enters in another activity. Similarly, when an activity pauses or resumes or destroys or when the user closes an application these callback methods invoke.
18) What is APK?
Android Package Kit (APK) also APK is the default file format in Android OS. The different applications in Android are available in APK format.
19) What is the Database for Android OS?
SQLite is an opensource database for Android. It stores data in the form of text file on the Android device. Android comes with the built in in SQLite database where as Google Firebase or Firestore database can also be used for Android apps.
20) Define API?
API also ‘Application Programming Interface’ are the standards or set of rules (code) which a program follows to connect and access a database or a web tool. The software companies release their API’s so the developers can use their API’s to communicate and get benefit from their website/database.
21) Define some of the abbreviations used in Android development?
AAPT – Android Asset Packaging Tool
ADB – Android Debug Bridge
ADK – Android Development Kit
AIDL – Android Interface Definition Language
ANR – Application Not Responding
API – Application Programming Interface
APK – Android Package Kit
GPS – Global Positioning System
IAP – In-App Purchase
JVM – Java Virtual Machine
JDK – Java Development Kit
LBS – Location-Based Services
NDK – Native Development Kit
SDK – Software Development Kit
TTS – Text To Speech
UX – User Experience
UI – User Interface
UDID – Unique Device Identifier
WAP – Wireless Application Protocol
XML – eXtensible Markup Language
So, these are some of the most common and important Android Developer Interview questions and answers. I hope these Interview questions and answers will help you to enhancing your knowledge about Android development. Similarly, it is going to help you with your job interviews. Basically, these are the 21 most important Interview questions for Android.
But, do you think have I missed something important that should be in this list? If so, then do inform me in the comments section below?
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