Top 30 Android Interview Questions &Answers
In the today’s world ,Android demanding is growing day to day.So the top questions which is asked by the interviewer is give below.
1 What is Android ?
Android is open source and linux based operating system which is used in mobile,smartphones and tablets computers etc.
It is acquired by the google in 2005 and launched it in 2007 for the smartphones ,tablets etc.
2 Who is the founder of Android ?
3 what is the main component/framework of android ?
It represents a single screen in which user can interact and perform operations.
It is same as frame/window
The operations are performed in the background is known as services
It is used to go one activity to another or transfer data between the activities .There are two types of intent(implicit & explicit)
It is used to share data between the applications
It enable user to access the data like audio,video etc within the application
resources -res/string, res/layout, res/drawable, res/menu etc
4 what is intent
It is a message which is passed between the component(like activity,services,broadcast receiver etc)
It is used to go one activity to another,transfer data between the activites or launch the activity etc.
There are two types of intent
5 How to go from one activity to another ?
Intent intent=new Intent(getApplicationContext,Activity2.class)
6 what do you mean by ANR ?
ANR stands for “Application not responding”.It is dialog box which appears when application not responding for long period of time
7 what are the Android activity life-cycle ?
onCreate:when android activity launched first time
onStart:when activity visible to the user
onResume:when activity start interact with the user
onPause:when activity not visible to the user
onStop:when activity is not visible to longer to the user
onRestart:when activity has stopped
onDestroy: when activity has finished
8 What do you mean by APK ?
APK stands for android packaging kit.It is the compressed file of application codes ,manifest(All classes are defined etc) , resources files(drawable,string ,menu etc) and other files.All the files are compressed into single unit is known as APK.
9 What do you mean by ADB ?
ADB stands for Android Debug Bridge.It is a debugging application which provides tools to the developer to perform action such as communicate to the emulator,browse the device,copy tools etc
10 What are the various storage methods in android ?
Android provides various storage methods.
1.shared preference: It store value in key-value pair formate
2.Internal storage: It store private data on the device memory
3.External storage: It store private data from the main device or secondary storage
4.SQLite database: It stores the relational database
11 What are the dialog boxes in Android ?
1Alert Dialog Box
2 Datepicker Dialog Box
3.TimePicker Dialog Box
4.Progress Dialog Box
12 What is the difference between implicit and explicit intent ?
when requested tasks are performed by the system/Os then it is known as implicit intent.
suppose we want to open the “www.google.com” url
Intent intent=new Intent( );
when requested tasks are exactly known then it is known as explicit intent
suppose there are two activities (Activity1 and Activity2).
I want to go from Activity1 to Activity2
Intent intent=new Intent(Activity1.this,Activity2.class);
13 which languages are used in the android development ?
Java is the primary language which is supported by Android Studio to develop android applcation.
Kotlin is secondary language which supported by Android studio.It it is little bit easier than the java,need to write less code etc.
C/C++ is also used to develope android app.It makes speed fast.
14 what is Toast in android ?
Android toast is a small pop-up which is used to show the message for the short period of time.
//code for display the message for the short period of time
Toast.makeText(getApplicationContext,” toast message”,Toast.LENGHT_SHORT).show( ));
//code for display the message for the long period of time
Toast.makeText(getApplicationContext,” toast message”,Toast.LENGHT_LONG).show( ));
15 What are the essential folders/items required in android project ?
There are the various folders/items required
16 What is AndroidManifest.xml in android ?
It is the root directory of the application and contains the complete information about the application.
All the Activity(.java class) of the application must be decleared inside the AndroidManifest.xml before run the application
17 What is APPT in Android ?
APPT stands for(Android Assest Packaging Tool)
It provides the tool to the developers in which they can packaging all the resources of the application into the single unit such as AndroidManifest.xml and other XML files.
18 What is Layout ? List the various layout in Android
Layout means simply creating GUI(Graphical User Interface) for our application.
Layout contains different widgets such as button,textview,radiobutton etc
Various Layouts are listed below
1 Linear Layout
2 Relative Layout
3 Table Layout
5 Cardview Layout
6 Recycleview Layout
7 Listview Layout
8 Frame Layout
19 What is fragment in android ?
Fragment is like a sub-activity/part of an activity/portion of an activity.
One fragment can display in multiple activities
Multiple fragment can display in one activity
20 What are the major component of android architecture ?
There are four major component of Android Architecture.
21 What is AIDL in android ?
AIDL stands for “Android Interface Definition Language”
It provides the medium to communicate between the client and server
It is an interface between the client and server to communicate each others.
22 What is “bundle” in android ?
Bundle is used to pass the data between the activities
We can pass any type of data(like Integer,String,Float etc)
Suppose we have two activities(FirstActivity.class and SecondActivity.class)
FirstActivity.class //Here i am passing “suman kumar” to the second Activity
Intent intent=new Intent(FirstActivity.this , SecondActivity.class);
Bundle bundle=new Bundle();
SecondActivity.class// Here i am getting “suman kumar” from the first Activity
Bundle bundle=getIntent.getExtras( );
Here we can get name “suman kumar”.
23 What are benifit of Android operating system ?
It is an open source (anyone can use it) and platform-Independent(support on window,Lunix or Mac) operating system.
It support different technologies like Wi-Fi,Bluetooth,Camera etc
24 How make HTTP request in android ?
HTTP stands for(Hyper Text Transfer Protocol)
1.By using Volley
2.By using Retrofit
3.By using AsyncTask
4,By using Jackson
25 Where the layouts are placed in android ?
Layouts are placed in XML files in Android
26.How we can get the layout “id” in android ?
We can get the layout id with the help of “findViewById”.
//textview layout in xml files
<Textview android id:"id/textview1" android height="match_parent" android weight="match_parengt"/>
//Get id in java class
27 What is Orientation in Android ?
Orientation means how do you want to keep your smartphone screen(Horizontally or Vertically).
It support two type of screen roration
1.portait:When device is Vertically aligned
2.Landscape:When device is Horizontally aligned
28 What are the flags used to run the Android Application ?
There are two types of flags are used to run the android application
29 List the various exceptions in Android
Some exceptions are given below
30 What is DDMS ?
DDMS stands for (Delvik Debug Monitor Server).
It is a debugging tools which has different features
Port forwarding services
Keep radio state information
Thread and Heap information