Android



1. What is Android?  

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. What are the advantages of Android?  

The following are the advantages of Android:
* 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.
Components can be reused and replaced by the application framework.
* Optimized DVM for mobile devices
* SQLite enables to store the data in a structured manner.
* Supports GSM telephone and Bluetooth, WiFi, 3G and EDGE technologies
* The development is a combination of a device emulator, debugging tools, memory profiling and plug-in for Eclipse IDE.



3. What Is the Google Android SDK?  

The Google Android SDK is a toolset that developers need in order to write apps on Android enabled devices. It contains a graphical interface that emulates an Android driven handheld environment, allowing them to test and debug their codes.




4. Describe Android application Architecture?  

Android application architecture has the following components.They are as follows -

Services - It will perform background functionalities
Intent - It will perform the inter connection between activities and the data passing mechanism
Resource Externalization - strings and graphics
Notification - light,sound,icon,notification,dialog box,and toast
Content Providers - It will share the data between applications




5. What is the Android Architecture?  

Android Architecture is made up of 4 key components:
- Linux Kernel
- Libraries
- Android Framework
- Android Applications



6. Explain about the exceptions of Android?  

The following are the exceptions that are supported by Android
* InflateException : When an error conditions are occurred, this exception is thrown
* Surface.OutOfResourceException: When a surface is not created or resized, this exception is thrown
* SurfaceHolder.BadSurfaceTypeException: This exception is thrown from the lockCanvas() method, when invoked on a Surface whose is SURFACE_TYPE_PUSH_BUFFERS
* WindowManager.BadTokenException: This exception is thrown at the time of trying to add view an invalid WindowManager.LayoutParamstoken.



7. What is the manifest file and how is it used?  

Every Android app must have this manifest file in its root directory named 'AndroidManifest.xml'. The file includes critical information about the app, including the Java package name for the application.



8. What is AAPT?  

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.



9. Name 4 ways Android allows you to store data?  

Any of the following 5 possible options are acceptable:
* SharedPreferences
* Internal Storage
* External Storage
* SQLite Database
* Network connection



10. Describe the APK format?  

The APK file is compressed the AndroidManifest.xml file, application code (.dex files), resource files, and other files. A project is compiled into a single .apk file.





11. What is An Intent?  

It is connected to either the external world of application or internal world of application ,Such as, opening a pdf is an intent and connect to the web browser.etc.



12. What is an explicit Intent?  

Android Explicit intent specifies the component to be invoked from activity. In other words, we can call another activity in android by explicit intent.



13. What is an implicit Intent?  

Implicit Intent doesn't specifiy the component. In such case, intent provides information of available components provided by the system that is to be invoked.



14. What is .apk extension?  

The extension for an Android package file, which typically contains all of the files related to a single Android application. The file itself is a compressed collection of an AndroidManifest.xml file, application code (.dex files), resource files, and other files. A project is compiled into a single .apk file.



15. What items or folders are important in every Android project?  

The developer should name at least 4 of these 6 items below, as these are essential within each Android project:
* AndroidManifest.xml
* build.xml
* bin/
* src/
* res/
* assets/





16. What is the importance of having an emulator within the Android environment?  

The emulator lets developers "play" around an interface that acts as if it were an actual mobile device. They can write and test codes, and even debug. Emulators are a safe place for testing codes especially if it is in the early design phase.



17. What language does android support to develop an application?  

Android applications has written using the java(Android SDK) and C/C++(Android NDK).



18. What is ANR?  

ANR stands for "Application Not Responding" It's a dialog box that appears when an application doesn't respond for more than 10 seconds (sometimes it can be less than 10 seconds). The ANR dialog box offers the user the option of either closing the app or waiting for it to finish running.



19. How do you avoid an ANR?  

A follow-up to the previous question, there are a number of possible answers here. What you want to hear is that you want as little work done as possible on the main thread, also known as the "UI thread". Since that is the core single thread that your application runs on, you would want to keep activities that require more complex computations or network and database connections, for example, on separate worker threads so as not to slow down the main thread.



20. What is .dex extension?  

Android programs are compiled into .dex (Dalvik Executable) files, which are in turn zipped into a single .apk file on the device. .dex files can be created by automatically translating compiled applications written in the Java programming language.



.Net Interview Question

PHP Interview Question

Java Interview Question

AngularJS Interview Questions