Android Interview Questions & Material

1) What is Android?

Ans: It is an open-sourced operating system that is used primarily on mobile devices, such as cell phones and tablets. It is a Linux kernel-based system that’s been equipped with rich components that allows developers to create and run apps that can perform both basic and advanced functions.

2)Who developed Android?

Ans:It was initially dveloped by Android Inc., which was financially backed by Google and later Google purchased it in 2005. The first Android-powered phone was sold in October 2008.

3)What is a ANR ?

Ans: ANR is short for Application Not Responding. Android systems shows this dialog, if application is performing too much of task on main thread and been unresponsive for a long period of time.

4) What is AAPT? 

Ans: AAPT is short for Android Asset Packaging Tool. This tool provides developers with the ability to deal with zip-compatible archives, which includes creating, extracting as well as viewing its contents.

5) What are the code names fo Android?
Ans: 
  • Aestro
  • Blender
  • Cupcake
  • Donut
  • Eclair
  • Froyo
  • Gingerbread
  • Honycomb
  • Ice Cream Sandwitch
  • Jelly Bean
  • Kitkat
  • Lollipop
6).  What is AIDL?

Ans: Android Interface Definition Language. It offers to define the clint’s interface requirements and moreover a service in order to communicate at same level with the help of inter process communications
         
7). What are the advantages of android?

Ans: The customer will be benefited from wide range of mobile applications to choose, since the monopoly of wireless carriers like AT&T and Orange will be broken by Google Android.
Features like weather details, live RSS feeds, opening screen, icon on the opening screen can be customized
Innovative products like the location-aware services, location of a nearby convenience store etc., are some of the additive facilities           in Android.
         
8). What is NDK?

Ans: 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.

9). What is Daydream?

Ans: Android 4.2’s Daydream is a smart screen-saver. Daydream lets       the Android device display useful and delightful information when idle or docked.  It lets us display photo slide shows, news headline etc.

10). What is Activities?

Ans: An activity is a single, focused thing that the user can do. when ever user click on GUI the next Activity will be start and new GUI set base on coding.

11).  What do you mean by android’s multiuser support?

Ans: In case of Android 4.2, a tablet can be shared among multiple users. When we switch users, it seems as if we are switching tablets: Each person gets her own set of settings, complete with home screen, apps, and everything.

12). Which database is used for Android?

Ans : We use SQLite database in Android.Some points about SQLite:
  • Open Source Database
  • SQLite is available on every Android device
  • It supports standard relational database features like 
  • a)SQL syntax 
  • b)transactions 
  • c)SQL statements
  • Very light weight database
  • Requires very little memory
  • Approx. 250KB
  • SQLite Database is automatically managed by Android Platform

 13.  How does Android system track the applications?

Ans: Android system assigns each application a unique ID that is called Linux user ID. This ID is used to track each application.
    
14).  What is an Action?

Ans: Action in Android glossary is something that an Intent sender wants done. It is a string value that is assigned to intent. Action string can be defined by the Android itself or by you as third party application developer.

15).  How can two Android applications share same Linux user ID and share same VM?

Ans:The applications must sign with the same certificate in order to share same Linux user ID and share same VM.
      
16). When does Android start and end an application process?

Ans: Android starts an application process when application's component needs to be executed. It then closes the process when it's no longer needed (garbage collection).
   
17). What are the core  building blocks of android?
     
 Ans: The core building blocks of android are:
Activity
View
Intent
Serv ice
Content Provider
Fragment etc.

18). What are the cycle methods of android activity?
    
Ans: There are 7 life-cycle methods of activity. They are as follows:
  • onCreate()
  • onStart()
  • onResume()
  • onPause()
  • onStop()
  • onRestart()
  • onDestroy()
19). Does android support other language than java?

Ans: 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.

20).What is Adapter? 

Ans: Adapter are bridging classes that bind data to Views(such as List Views) used in the user interface. The adapter is responsible for creating for creating the child Views used to represent each item within the parent View, and providing access to the underlying data.

21). What are the different storage methods in android

Ans :Android offers several different options for data persistence.
  • Shared Preferences – Store private primitive data in key-value pairs. This sometimes gets limited as it offers only key value pairs. You cannot save your own java types.
  • Internal Storage – Store private data on the device memory
  • External Storage – Store public data on the shared external storage
  • SQLite Databases – Store structured data in a private database. You can define many number of tables and can store data like other RDBMS.

22)  What language is supported by Android for application       development 

Ans: The main language supported is Java programming language. Java is the most popular language for app development, which makes it ideal even for new Android developers to quickly learn to create and deploy applications in the Android environment.

23). What is Intent?
 
Ans: An Intent is exactly what it describes. It's an "intention" to do an action.An Intent is basically a message to say you did or want something to happen. Depending on the intent, apps or the OS might be listening for it and will react accordingly.

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

24). What is AVD?
 
Ans: AVD Stand for Android Virtual Device (emulator), The Android SDK includes a mobile device emulator - a virtual mobile device that runs on your computer.

25) What attribute values should be localized?

Ans: The attribute values that can be displayed to users should be localized. For example: label, icon etc.

26). What are containers?

Ans: Containers holds objects and widgets together, depending on which items are needed and in what arrangement they need to be in. Containers may hold labels, fields, buttons, or even child containers, as examples.

27). How to Remove Desktop icons and Widgets? 

Ans: Press and Hold the icon or widget. The phone will vibrate and on the bottom of the phone you will see an option to remove. While still holding the icon or widget drag it to the remove button. Once remove turns red drop the item and it is gone

28). Does Android support Adobe Flash in the browser?

Ans: Flash support varies by device with Android 2.1. The Samsung Acclaim does not have Flash support upon launch, but the HTC Desire will support Flash Lite 4.0 running Android 2.1. Flash 10.1 support is coming to Android-powered phones with Android 2.2.



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