Android Interview Questions | Eklavya Online

Android Interview Questions

The Implicit intent is used to invoke the system components.

Android is a customized Linux 3.6 kernel.

There are 7 life-cycle methods of activity. They are as follows:

  • onCreate()
  • onStart()
  • onResume()
  • onPause()
  • onStop()
  • onRestart()
  • onDestroy()

A content provider is used to share information between Android applications.

DDMS stands for Dalvik Debug Monitor Server. It gives the wide array of debugging features:

  • Port forwarding services
  • Screen capture
  • Thread and heap information
  • Network traffic tracking
  • Location data spoofing

The files which can be injected for the building up of a process are called as application resource file.

Following is a list of components of Android application architecture:

  • Services: Used to perform background functionalities.
  • Intent: Used to 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.

APK is a short form stands for Android Packaging Key. It is a compressed key with classes, UI’s, supportive assets and manifest. All files are compressed to a single file is called APK.

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

An explicit intent is used to invoke the activity class.

Application widgets are miniature application views that can be embedded in other applications and receive periodic updates.

It is a kind of message or information that is passed to the components. It is used to launch an activity, display a web page, send SMS, send email, etc. There are two types of intents in android:

  • Implicit Intent
  • Explicit Intent

The fragment is a part of Activity by which we can display multiple screens on one activity.

The Android architecture consists of 4 components:

  • Linux Kernal
  • Libraries
  • Android Framework
  • Android Applications

A unique Linux ID is assigned to each application in android. It is used for the tracking of a process.

  1. Aestro
  2. Blender
  3. Cupcake
  4. Donut
  5. Eclair
  6. Froyo
  7. Gingerbread
  8. Honeycomb
  9. Ice Cream Sandwich
  10. Jelly Bean
  11. KitKat
  12. Lollipop
  13. Marshmallow

Open-source: It means no license, 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 a highly optimized virtual machine for mobile devices, called DVM (Dalvik Virtual Machine).

ADT stands for Android Development Tool. It is used to develop the applications and test the applications.

Intent i = new Intent(getApplicationContext(), ActivityTwo.class);
startActivity(i);

Following are two types of flags to run an application in Android:

  • FLAG_ACTIVITY_NEW_TASK
  • FLAG_ACTIVITY_CLEAR_TOP

View elements can be identified using the keyword findViewById.

ADB stands for Android Debug Bridge. It is a command line tool that is used to communicate with the emulator instance.

The portable wi-fi hotspot is used to share internet connection to other wireless devices.

Yes, an 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.

  • Alert Dialog
  • Progress Dialog
  • Date Picker Dialog
  • Time picker Dialog

View Group is a collection of views and other child views. It is an invisible part and the base class for layouts.

A service is a component that runs in the background. It is used to play music, handle network transaction, etc.

A singleton class is a class which can create only an object that can be shared by all other classes.

An android toast provides feedback to the users about the operation being performed by them. It displays the message regarding the status of operation initiated by the user.

NDK stands for Native Development Kit. By using NDK, you can develop a part of an app using native language such as C/C++ to boost the performance.

The various storage provided by android are:

  • Shared Preferences
  • Internal Storage
  • External Storage
  • SQLite Databases
  • Network Connection

Layouts in Android are placed as XML files.

The core building blocks of Android are:

  • Activity
  • View
  • Intent
  • Service
  • Content Provider
  • Fragment etc.

Android is an open-source, Linux-based operating system used in mobiles, tablets, televisions, etc.

An adapter is used to create a child view to present the parent view items.

An opensource and lightweight relational database for mobile devices.

In sleep mode, CPU is slept and doesn’t accept any commands from android device except Radio interface layer and alarm.

The following folders are declared as impotent in android:

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

ANR stands for Application Not Responding. It is a dialog box that appears if the application is no longer responding.

  • Inflate Exception
  • Surface.OutOfResourceException
  • SurfaceHolder.BadSurfaceTypeException
  • WindowManager.BadTokenException

Layouts in Android are placed in the layout folder.

We can change bitmap images into nine sections with four corners, four edges, and an axis.

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

AAPT is an acronym for android asset packaging tool. It handles the packaging process.

In Android, a drawable folder is compiled a visual resource that can use as a background, banners, icons, splash screen, etc.

We use bundles to pass the required data to various subfolders.

The Google Android SDK is a toolset which is used by developers to write apps on Android-enabled devices. It contains a graphical interface that emulates an Android-driven handheld environment and allows them to test and debug their codes.