Tuesday, 3 October 2017

Interview/Viva Questions on Android Application Development

                       Following is the list of Interview / Viva questions on Android Application Development which can be asked in Job interviews or Oral exams:

1. Who are the founders of Android?
Ans: Andy RubinRich Miner, Nick Sears, and Chris White

2. What are the advantages of Android?

Ans:  Multitasking, Notification, Widgets, Millions Of apps, Opensource framework, Inbuilt support for the Flash

3. Which languages are supported by Android other than Java for Application Development?
Ans: C, C++, Go, Kotlin

4. Which minimum Java version you required for Android Studio?

Ans: JDK 1.8

5. What are the minimum system requirements for installing Android Studio?

RAM: 3 GM RAM Minimum, 8 GB RAM recommended; plus 1 GB for the Android Emulator
OS: 64 bit Distribution capable of running 32 bit applications
Hard Disk Space: 2 GB minimum (500 MB for IDE and 1.5 GB for Android SDK); 4 GB recommended.
Screen Resolution: 1280*800 (minimum)


RAM: 3 GM RAM Minimum, 8 GB RAM recommended; plus 1 GB for the Android Emulator
OS: Windows 7/8/10 32 or 64 bit
Hard Disk Space: 2 GB minimum (500 MB for IDE and 1.5 GB for Android SDK); 4 GB recommended.
Screen Resolution: 1280*800 (minimum)
6. Explain the architecture of Android OS?
Ans: Check link https://www.comrevo.com/2018/10/architecture-of-android-operating-system.html .

7. What is activity in Android?

Ans: Activity represents single screen with user interface. It is a subclass of ContextThemeWrapper class.

8. Explain Activity Life Cycle in Android.

                        Android Activity Life Cycle is controlled by 7 methods of android.app.Activity class.
                        These 7 methods are as follows:
onCreate: It is called when activity is first created.
onStart: It is called when activity is becoming visible to the user.    
onResume: It is called when activity will start interacting with the user.  
onPause: It is called when activity is not visible to the user.
onStop: It is called when activity is no longer visible to the user.
onRestart: It is called after your activity is stopped, prior to start.
onDestroy: It is called before the activity is destroyed.  

For details, check link: https://developer.android.com/guide/components/activities/activity-lifecycle     

9. What is NDK?

Ans: NDK (Native Development Kit) is a toolset which enables you to implement part of Android Application in native code using languages C or C++.

10. What is Android SDK?

Ans: SDK stands for Software Development Kit that enables developers to create applications for the Android platform. The Android SDK includes sample projects with source code, development tools, an emulator, and required libraries to build Android applications.
11. What is SQLite? Which type of database it is?
Ans: SQLite is database system contained in a C library. It is different than the conventional Client-Server database systems. It is embedded into the end program e.g. Web browsers.
                It is a relational database system and support the SQL standards.

How to create Android App using SQLite database, check in following link: 

12. What is the difference between Internal Storage and External Storage in Android application?

Ans: Internal storage is used to save Application data and it is particular to that application i.e. can not be accessed by other applications. 
                   When you install any app, data files related to App get saved to Internal storage and when you uninstall app, these data files get removed.
                    External storage consists of two types of files: Private files and Public files. Private files are particular to the application i.e. they can not be accessed by other applications and when you uninstall app, these private files get removed. Public files can be accessed by other applications. These public files in external storage persist even after the app is uninstalled. 
                    Check link to know how to use internal storage: https://www.tutorialspoint.com/android/android_internal_storage.htm.
                   Check Link to know how to use external storage: https://www.journaldev.com/9400/android-external-storage-read-write-save-file

13. Mention the name of Class to be used for developing Android Audio Music Player?

Ans: MediaPlayer 

How to create Audio Music Player App for Android, check in following link:

14. Mention the name of Class to be used for developing Android Video Music Player?

Ans: MediaController

How to create Video Music Player App for Android, check in following link:

15. What is APK? What is the full form?

Ans: APK stands for Android application package (APK). It is the package file format used by the Android operating system for distribution and installation of application software and middleware.

16. Android Studio is based on which IDE?

Ans: IntelliJ IDEA

17. What is IntelliJ IDEA? Who has developed it?

Ans: IntelliJ IDEA is a Java integrated development environment (IDE) for developing computer software. It is developed by JetBrains (formerly known as IntelliJ)

18. What is Gradle?

Ans: In Android Studio, Gradle is a custom build tool used to build android packages (apk files) by managing dependencies and providing custom build logic.

19. How events are handled in Android Application?    

Ans: Check link https://www.comrevo.com/2019/09/android-app-for-addition-of-two-numbers.html

20. How permissions are granted in Android Application? What is the difference between tags <uses-permission> and <uses-feature> ?
Ans: Permissions are provided to Android Apps by using <uses-permission> or <uses-feature> tag in AndroidManifest.xml.

If our app is requesting any hardware permission e.g. camera by using <uses-permission>; then Google Play filters out this App from the devices which do not provide that hardware. 
We can control this filtering by using <uses-feature> tag. We can disable filtering by adding attribute android:required="false" in tag <uses-feature>.
For details, check link https://developer.android.com/guide/topics/manifest/uses-permission-element

21. What is intent in Android? What are implicit intent & explicit intent?

Ans: Intent is a class which is used to launch an activity, display a web page, send sms, send email etc.
                      There are two ways of using Intent class. Those are Implicit Intent and Explicit Intent.
                      Implicit Intent is used to invoke the system components (e.g. classes provided by Android SDK like Uri) while Explicit Intent is used to invoke external class (e.g. other Activity class created by us).  

Implicit Intent

Intent i=new Intent(Intent.ACTION_VIEW); 

Explicit Intent

Intent i = new Intent(getApplicationContext(), NewActivity.class); 

Note: startActivity() method is provided by Activity class.

For details, check link: https://www.javatpoint.com/android-intent-tutorial.  

22. What are the steps to get Google Maps API key?
Ans: Check link: https://www.comrevo.com/2019/09/how-to-get-google-maps-api-key.html

23. How to create Android App for getting Current Location on Google Maps Activity?
Ans: Check link: https://www.comrevo.com/2019/09/android-app-to-get-current-location-on-google-maps.html 

                         Find Interview / Viva questions on Advanced Java in this link http://www.comrevo.com/2017/10/interview-questions-on-advanced-java.html.

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