Top android interview questions 2019

Top android interview questions 2019

These are some probable question on android.you can refer these are as quick refresh knowledge about android and android development. 

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1.Who is the founder of Android?

Android Inc. was founded in Palo Alto, California, in October 2003 by Andy Rubin, Rich Miner, Nick Sears, and Chris White.

2.What is android?

Android is a mobile operating system developed by Google.

3. what are versions of android os?

·         Android 1.5: Android Cupcake.

·         Android 1.6: Android Donut.

·         Android 2.0: Android Eclair.

·         Android 2.2: Android Froyo.

·         Android 2.3: Android Gingerbread.

·         Android 3.0: Android Honeycomb.

·         Android 4.0: Android Ice Cream Sandwich.

·         Android 4.1 to 4.3.1: Android Jelly Bean.

4. What is the latest version of Android?

The Latest Version of Android is 9.0, Pie.

5. What is API and SDK?

API is an interface that allows software programs to interact with each other.

SDK is a set of tools that can be used to develop software applications targeting a specific platform.

6. what is the full form of api in android?

Ans. application program interface (API).

7. what is the full form of SDK in android?

Ans. software development kit.

8. what is emulator in android?

An Android emulator is an Android Virtual Device (AVD) that represents a specific Android device. You can use an Android emulator as a target platform to run and test your Android applications on your PC.

9. what is activity in android studio?
An Android activity is one screen of the Android app's user interface. In that way an Android activity is very similar to windows in a desktop application.

10. what are different types of activity templates in android studio?

Basic Activity, Bottom Navigation Activity, Empty Activity, Fullscreen Activity, Login Activity,etc

11. What is activity life cycle?

When an activity moves from being launched to being destroyed, it triggers key activity lifecycle methods: the onCreate() and onDestroy() methods

12. what are views in android?

View is a basic building block of UI (User Interface) in android. A view is a small rectangular box which responds to user inputs. Eg: EditText , Button , CheckBox , etc.

13. Name some predefined views in android?

A partial list of available widgets includes Button , TextView , EditText , ListView , CheckBox , RadioButton , Gallery , Spinner , and the more special-purpose AutoCompleteTextView , ImageSwitcher , and TextSwitcher

14. What is layout?

In Android, an XML-based layout is a file that defines the different widgets to be used in the UI and the relations between those widgets and their containers.

15. What are types of layout?

• AbsoluteLayout
• FrameLayout
• LinearLayout
• RelativeLayout
• TableLayout etc,

16. What is difference between Relative Layout and Linear Layout?

LinearLayout : A layout that organizes its children into a single horizontal or vertical row.

RelativeLayout is a view group that displays child views in relative positions. Or in RelativeLayout area (such as aligned to the bottom, left or center).

17.You want to change text of button, what attribute of Button will you change in xml file?

android:text="@string/button_text"    

18. What are different layout attributes?

android:id, layout_width, layout_height, layout_marginTop, layout_gravity, layout_weight

19. What is onclick listener?

Onclick handlers are used to execute a part of code when a button or other part of the user interface is touched (clicked).

20. What is meant by Services?

Service is an Android component which runs in the background and acts independently. It does not provide any user interface.

21. What is the use of AppCompatActivity?

The AppcompactActivity is a class which extends FragmentActivity that is Base class for activities that use the support library action bar features.

22. How to start an activity from within the activity?

This can be achieved through Intents. You can make Intents to link activities within your app as well as call other apps.

23. What is Intent?

Android has an Intent class when the user has to navigate from one Activity to another. Intent displays notifications from the device to the user and then the user can respond to the notification if required.

24 Explain Implicit and Explicit Intents.

Implicit Intent calls the system components while explicit Intents invoke the Activity class.

25. What is Toast?

Andorid Toast can be used to display information for the short period of time.

26. How do we create Toast?

Toast toast = Toast.makeText(getApplicationContext(),

        "This is a message displayed in a Toast",

        Toast.LENGTH_SHORT);

        toast.show();

27. How do I get text from EditText?

demo.getText();

28. How to we make a view interactive?

Drawing a UI is only one part of creating a custom view. You also need to make your view respond to user input in a way that closely resembles the real-world action you're mimicking. Users also sense subtle behavior or feel in an interface, and react best to subtleties that mimic the real world.

29. How to add a event listener to a view?

An event listener is an interface in the View class that contains a single callback method. These methods will be called by the Android framework when the View to which the listener has been registered is triggered by user interaction with the item in the UI.

30. What are different kinds of event listeners?

onClick(),onLongClick(),onFocusChange(),onKey(),onTouch(),onCreateContextMenu

31. How do I add permission to AndroidManifest?

·  Step 1 : Go to app -> src -> main -> AndroidManifest.xml.

·  Copy following code: <uses-permission android:name="android.permission.INTERNET" />

32. What is most widely used database for Android app local storage?

SQLite

33. What is SQLite?

SQLite is a popular choice as embedded database software for local/client storage in application software such as web browsers.

34. What are advantages of using SQlite?

SQLite does have a data constraints feature and can edit or drop tables without loading them into memory. SQLite works on the data stored on the disk and is slower compared to Core Data.

35. What are services?

Android service is a component that is used to perform operations on the background such as playing music, handle network transactions, interacting content providers etc.

36. When to use services?

If you want the service code to run in a Background

37. You want to design a login screen what layout will you use?

LinearLayout

38. What sensors are available in Android Mobile?

·         Accelerometer. An accelerometer detects acceleration, vibration, and tilt to determine movement and exact orientation along the three axes. ...

·         Gyroscope. ...

·         Magnetometer. ...

·         GPS. ...

·         Proximity Sensor. ...

·         Ambient Light Sensor. ...

·         Microphone. ...

·         Touchscreen Sensors.

39. What are android permissions?

The purpose of a permission is to protect the privacy of an Android user. Android apps must request permission to access sensitive user data

40. Where do you write android permissions?

Manifest.xml

41. What are two permissions associated with location in android?

ACCESS_FINE_LOCATION, ACCESS_COARSE_LOCATION

42. How can we retrieve anything from database?

using an object of the Cursor class.

43. What is .apk extension in Android?

It is a default file format that is used by Android Operating System. Application Package Kit (APK) is used for installation of mobile apps. The .apk contains other code.

44. Tell some common Android APIs.

-  Databases are commonly used for caching data. So SQLite and Content provider and Sync Adapter API are provided for Android.

-  For networking most developers use 3rd party libraries like Okhttp, retrofit, volley.