Dear readers, these Android Interview Questions have been outlined specially to get you familiar with the nature of questions you'll experience during your interview for the subject of Android. As per my experience, great interviewers barely plan to ask any specific question during your interview, normally questions start with some essential concept of the subject, and afterward, they proceed based on advance discussion and what you reply.

Here is the list of android questions and answers asked in interviews

Q1 ) What is Android?

A1) 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.

Q2 ) Describe Android Application Architecture?

A2) Android application architecture has the following components. They are as follows −

• Services − It will perform background functionalities
  
• Intent − It will perform the interconnection 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
  

Q3 ) What is An Activity?

A3) Activity performs actions on the screen. If you want to do any operations, we can do with activity

Q4 ) What is the APK format?

A4) 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.

Q5 ) What is An Intent?

A5) It is connected to either the external world of application or the internal world of application, Such as opening a pdf is intent and connect to the web browser, etc.

Q6 ) What is an Explicit Intent?

A6) Android Explicit intent specifies the component to be invoked from activity. In other words, we can call another activity in android by explicit intent.

Q7 ) What is an Implicit Intent?

A7) Implicit Intent doesn't specify the component. In such a case, intent provides information of available components provided by the system that is to be invoked.

Q8 ) What is An android manifest file?

A8) 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.

Q9 ) What language does Android support to develop an application?

A9) Android applications have written using java(Android SDK) and C/C++(Android NDK).

Q10 ) What does ADT stand for?

A10) ADT stands for Android development tool, This is useful to develop the applications and test the applications.

Q11 ) What are tools are placed in An Android SDK?

A11) Android SDK collaborated with Android Emulator, DDMS(Dalvik Debug Monitoring Services), AAPT(Android Asset Packaging Tool), and ADB(Android debug bridge)

Q12 ) What is a view group in android?

A12) View group is a collection of views and other child views, it is an invisible part and the base class for layouts.

Q13 ) What is a service in android?

A13) The Service is like an activity to do background functionalities without UI interaction.

Q14 ) What is a content provider in android?

A14) A content provider component supplies data from one application to others on request. Such requests are handled by the methods of the ContentResolver class. A content provider can use different ways to store its data and the data can be stored in a database, in files, or even over a network.

Q15 ) What are the notifications available in android?

A15)

• Toast Notification − It will show a pop-up message on the surface of the window
  
• Status Bar Notification − It will show notifications on the status bar
  
• Dialogue Notification − It is an activity-related notification.
  

Q16 ) What is a container in android?

A16) The container holds objects,widgets,labels,fields,icons,buttons.etc.

Q17 ) What is ADB in android?

A17) It acts as a bridge between emulator and IDE, it executes remote shell commands to run applications on an emulator.

Q18 ) What is ANR in android?

A18) ANR stands for application is not responding, basically it is a dialog box that appears when the application is not responding.

Q19 ) What is an Adapter in android?

A19) The Adapter is used to create child views to represent the parent view items.

Q20 ) What are the key components in android architecture?

A20)

• Linux Kernel
  
• Libraries
  
• Android Framework
  
• Android applications.
  
• What does the intent filter do in android?
  
• Intent filters are filter out the intents.
  

Q21 ) Where layouts are placed in android?

A21) In The Layout folder, layouts are placed as XML files

Q22 ) What is the nine-patch images tool in android?

A22) We can change bitmap images in nine sections as four corners, four edges, and an axis

Q23 ) How many dialog boxes do support in android?

A23) AlertDialog, ProgressDialog,DatePickerDialog, and TimePickerDialog

Q24 ) What are the exceptions available in android?

A24)InflateException,Surface.OutOfResourceException,SurfaceHolder.BadSurfaceTypeException,and WindowManager.BadTokenException

Q25 ) What is the order of the dialog-box in android?

A25) Positive, Neutral, Negative.

Q26 ) What are the different storages available in android?

A26) Shared Preferences, Internal Storage, External Storage, SQLite Databases, and Network Connection

Q27 ) What is a Sticky Intent in android?

A27) Sticky Intent is also a type of intent that allows the communication between a function and a service, for example, sendstickybroadcast() performs the operations after completion of intent also.

Q28 ) How to Translate in Android?

A28) Android uses Google translator to translate data from one language into another language and placed it as a string while development

Q29 ) How is the use of web view in Android?

A29) WebView is a UI component that can display either remote web-pages or static HTML.

Q30 ) What are shared preferences in android?

A30) Shared preferences are the simplest mechanism to store the data in XML documents.

Q31 ) Why can't you run java byte code on Android?

A31) Android uses DVM (Dalvik Virtual Machine ) rather than using JVM(Java Virtual Machine), if we want, we can get access to the .jar file as a library.

Q32 ) How does android track the application in the process?

A32) Android provides a Unique ID to all applications is called a Linux ID, this ID is used to track each application.

Q33 ) How to change the application name after its deployment?

A33) It's not truly recommended to change the application name after its deployment, if we change, it will impact all other internal components.

Q34 ) Define the application resource file in android?

A34) JSON,XML bitmap.etc are application resources.You can inject these files to the build process and can load them from the code.

Q35 ) How to launch an activity in android?

A35) Using with intent, we can launch an activity.

Intent intent = new Intent(this, MyTestActivity.class);

startActivity(intent);

Q36 ) How do you pass the data to sub-activities android?

A36) Using with Bundle, we can pass the data to sub-activities.

Bundle bun = new Bundle();

bun.putString("EMAIL", "contact@tutorials.com");

Q37 ) What is a singleton class in android?

A37) A class that can create only an object, that object can be shareable to all other classes.

Q38 ) What is a fragment in android?

A38) Fragment is a piece of activity, if you want to do turn your application 360 degrees, you can do this by fragment.

Q39 ) What is sleep mode in android?

A39) Sleep mode means the CPU will be sleeping and it doesn't accept any commands from the android device except the Radio interface layer and alarm.

Q40 ) Which kernel is used in android?

A40) Android is a customized Linux 3.6 kernel.

Q41 ) How to update UI from service in android?

A41) Use a dynamic broadcast receiver in the activity, and send a broadcast from the service. Once the dynamic receiver is triggered update UI from that receiver.

Q42 ) What folders are impotent in the android project?

A42)

• AndroidManifest.xml
  
• build.xml
  
• bin/
  
• src/
  
• res/
  
• assets/
  

Q43 ) What are application Widgets in android?

A43) App Widgets are miniature application views that can be embedded in other applications (such as the Home screen) and receive periodic updates. These views have referred to as Widgets in the user interface, and you can publish one with an App Widget Provider.

Q44 ) How do you find any view element into your program?

A44) Using with findViewById we can find the view element.

Q45 ) What is a drawable folder in android?

A45) A compiled visual resource that can be used as a background, banners, icons, splash screen, etc.

Q46 ) What is the type of flags to run an application in android?

A46) FLAG_ACTIVITY_NEW_TASK
         FLAG_ACTIVITY_CLEAR_TOP.

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