Android Interview Questions

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Android programming is growing day by day. The question asked by interviewers in android is given below. A list of top android interview questions and answers are given below.
                                     

1) What is Android?

-- Android is a open-source, linux-based operating system that is used in mobiles, tablets, television etc.
2) Who is the founder of Android?

-- Andy Rubin.
3) Explain the Android Application Architecture.

-- Following list of components of Android Application Architecture.

  • Services : Used to perform background functionality.
  • Intent : Used to perform the inter connection between activities and the data passing mechanism.
  • Resource Externalization : strings and graphics.
  • Notification : Light, icon, sound, notification, dialog box and toast.

4) What are the code names of Android?

1. Aestro
2. Blender
3. Cupcake
4. Donut
5. Eclair
6. Froyo
7. Gingerbread
8. Honycomb
9. Ice cream sandwich
10. Jelly bean
11. Kitkat
12. Lollipop
13. Marshmallow


5) What are the advantages of android?

  • Open-source: It means no licence, distribution and development fee.
  • Platform-independent: It supports windows, mac and linux platforms.
  • Supports various technologies: It supports camera, Bluetooth, WiFi, speech, EDGE etc. technologies.
  • Highly optimized Virtual Machine: Android uses highly optimized virtual machine for mobile devices, called DVM (Dalvik Virtual Machine).


6) Does android support other language than java?

-- Yes, android app can be developed in C/C++ also using android NDK (Native Development Kit). It makes the performance faster. It should be used with android SDK.


7) What are the core building blocks of android?

-- The core building blocks of android are:
  • Activity
  • View
  • Intent
  • Service
  • Content Provider
  • Fragment etc.

8) What is activity?

-- Activity is like a frame or window in java that represents GUI. It represents one screen of android.


9) What are the life cycle methods of android activity?

-- There are 7 life-cycle methods of activity. They are as follows:
  • onCreate()
  • onStart()
  • onResume()
  • onPause()
  • onStop()
  • onRestart()
  • onDestroy()

10) What is intent?

-- It is a kind of message or information that is passed to the components. It is used to launch an activity, display a web page, send sms, send email etc.

-- There are two types of intents in android:
  • Implicit Intent
  • Explicit Intent

11) What is implicit intent in android?

-- Implicit intent is used to invoke the system components.


12) What is explicit intent in android?

-- Explicit intent is used to invoke the activity class.


13) How to call another activity in android?

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


14) What is service in android?

-- A service is a component that runs in the background. It is used to play music, handle network transaction etc.


15) What is the name of database used in android?

  • SQLite : An opensource and lightweight relational database for mobile devices.

16) What is AAPT?

-- AAPT is an acronym for android asset packaging tool. It handles the packaging process.


17) What is content provider?

-- Content providers are used to share information between android applications.


18) What is fragment?

-- Fragment is a part of Activity. By the help of fragments, we can display multiple screens on one activity.


 19) What is ADB?

-- ADB stands for Android Debug Bridge. It is a command line tool that is used to communicate with the emulator instance.


 20) What is NDK?

-- NDK stands for Native Development Kit. By using NDK, you can develop a part of app using native language such as C/C++ to boost the performance.


21) What is ANR?

-- ANR stands for Application Not Responding. It is a dialog box that appears if the application is no longer responding.


22) What is the Google Android SDK?

-- The Google Android SDK is a toolset which is used by developers to write apps on Android enabled devices.

-- It contains a graphical interface that emulates an Android driven handheld environment and allow them to test and debug their codes.


23) What is an APK format?

-- APK is a short form stands for Android Packaging Key.

-- All files are compressed to a single file is called APK.


 24) Which language does Android support to develop an application?

-- Android applications are written by using the java (Android SDK) and C/C++ (Android NDK).


25) What is ADT in Android?

-- ADT stands for Android Development Tool. It is used to develop the applications and test the applications.


26) What is View Group in Android?

-- View Group is a collection of views and other child views. It is an invisible part and the base class for layouts.


27) What is Adapter in Android?

-- An adapter is used to create a child view to present the parent view items.


28) What do you mean by a drawable folder in Android?

-- In Android, a drawable folder is compiled visual resource that can use as a backgrounds, banners, icons, splash screen etc.


29) Name the dialog box which are supported by android?

  • Alert Dialog
  • Progress Dialog
  • Date Picker Dialog
  • Time picker Dialog

30) What are the basic tools used to develop an android app?

-- JDK
-- Android-studio-bundle-162.3764568-windows software
-- SDK Tools