Android Questions & Answers (Compiled from UPSC, SSC ,PSC ,IBPS previous question papers)

What is the importance of XML-based layouts?
The use of XML-based layouts provides a consistent and somewhat standard means of setting GUI definition format. In common practice, layout details are placed in XML files while other items are placed in source files.

What are the life cycle methods of android activity?
There are 7 life-cycle methods of activity. They are as follows:
1. onCreate()
2. onStart()
3. onResume()
4. onPause()
5. onStop()
6. onRestart()
7. onDestroy()

What do ADT stands for?
ADT stands for Android development tool,This is useful to develop the applications and test the applications.

What items are important in every Android project?
These are the essential items that are present each time an Android project is created:
– AndroidManifest.xml
– build.xml
– bin/
– src/
– res/
– assets/

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

What language does android support to develop an application?
Android applications has written using the java(Android SDK) and C/C++(Android NDK).

How can we use escape characters as attributes?
Escape characters usually have backlashes before them. For instance, one can create a newline character with the use of ‘\\n’

Differentiate Activities from Services.
Activities can be closed, or terminated anytime the user wishes. On the other hand, services are designed to run behind the scenes, and can act independently. Most services run continuously, regardless of whether there are certain or no activities being executed.

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

What is An android manifest file?
Every application must have an AndroidManifest.xml file (with precisely that name) in its root directory. The manifest file presents essential information about your app to the Android system, information the system must have before it can run any of the app's code.

What is Android Architecture?
Android Architecture consists of 4 main elements
- Linux Kernel
- Android Framework
- Android Applications
- Libraries

Describe Activities.
Activities are what you refer to as the window to a user interface. Just as you create windows in order to display output or to ask for an input in the form of dialog boxes, activities play the same role, though it may not always be in the form of a user interface.

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.

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.

What is adb?
Adb simply stands for Android Debug Bridge. It presents developers with the power to perform shell commands that are remote. Its major work is to permit and direct communication towards and from the emulator port.

What is the use of an activityCreator?
An activityCreator is the first step towards the creation of a new Android project. It is made up of a shell script that will be used to create new file system structure necessary for writing codes within the Android IDE.

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).

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.

What is Orientation?
Orientation dictates whether the LinearLayout is represented as a column or a roll, when it is set using setOrientationa(). The values are set as VERTICAL or as HORIZONTAL.

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.

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 Sandwitch
10. Jelly Bean
11. Kitkat
12. Lollipop
13. Marshmallow

What is the APK format?
The Android packaging key is compressed with classes,UI's, supportive assets and manifest.All files are compressed to a single file is called APK.

What is ANR?
ANR is the acronym for Application Not Responding. When an application is unresponsive for a long time, the dialogue shows up to let the user know about the situation.

What are intents?
Intents display messages of notification from within the Android enabled device to the user. Intents are used to notify the user when a particular state occurs, and users have the opportunity to respond to the notification.

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.

Explain the Android application Architecture.
Following is a list of components of Android application architecture:
- Services: Used to perform background functionalities.
- Intent: Used to 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.

What is An Activity?
Activity performs actions on the screen.If you want to do any operations, we can do with activity

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.

Who is the founder of Android?
Andy Rubin.

What is Android?
Android is a stack of software for mobile devices which includes an Operating System, middleware and some key applications. The application executes within its own process and its own instance of Dalvik Virtual Machine.c

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