Android Interview Question

What are the advantages of Android?

• It is modest and potent SDK (Software Development Kit) and importantly it is open source, meaning that Licensing, Distribution or Development fee is not required.
• Easy to Import third party Java library.
• Android Supports platforms such as Linux, Mac Os, Windows.
•  Ground-breaking products like Location-Aware services, location of a nearby convenience store etc. are quite helpful.
• Components of Android can be reused and replaced by the application framework. Has optimized DVM for mobile devices. SQLite enables to store the data in a structured manner.
• Android Supports GSM telephone and Bluetooth, WI-Fi, 3G and EDGE technologies. The development is a combination of a device emulator, debugging tools, memory profiling and plug-in for Eclipse IDE.

What are the different phases of the Activity life cycle?

As an activity transitions from state to state, it is notified of the change by calls to the following protected methods:

•  void onCreate(Bundle savedInstanceState)
•  void onStart()
•  void onRestart()
•  void onResume()
•  void onPause()
•  void onStop()
•  void onDestroy()

These seven methods define the entire lifecycle of an activity.

What is an Explicit Intent?

In an explicit intent, the activity that is required to respond to the intent is specified. To be precise, the target components are explicitly designated. This is typically used for application internal messages.

What is an Implicit Intent?

In an implicit intent, only the intent is declared and the activity that can respond to the intent is left to the platform. Here the target component is not declared, hence it is usually used for activating components of other applications as well.

What is an AndroidManifest file?

Applications confirm their components like the .apk file that also holds the application’s code, files, and resources in a manifest file that’s bundled into the Android package. The manifest is a structured XML file and is always named AndroidManifest.xml for all applications. It is also used for naming libraries the application that needs to be linked and identifying any permissions the application expects to be granted.

What’s the difference between a file, a class and an activity in android?

• File – It is a chunk of arbitrary information, or resource for storing information.
• Class – It’s a compiled form of Java file. Android uses the .class files to produce an executable apk
• Activity – An activity is the comparable to a Frame/Window in GUI toolkits. It is not a file or a file type it is just a class that can be extended in Android for loading UI elements on view.

What is the significance of the .dex files?

Android programs are compiled into ‘.dex’ (Dalvik Executable) files, which are zipped into a single .apk file on the device. ‘.dex’ files can be created by translating compiled applications written in Java.

What does ADT stand for?

ADT stands for Android Development Tools. The Android SDK contains several tools and utilities to help create, test and debug your projects.

What are the different tools in Android and explain them?

• The Android SDK and Virtual Device Manager:

It is used to create and manage Android Virtual Devices (AVD) and SDK packages. The AVD holds an emulator, letting you specify supported SDK version, screen resolution, SD card storage available and available hardware abilities such as touch screens and GPS.

• The Android Emulator:

Android Emulator is an implementation of the Android virtual machine designed to run within a virtual device on the development computer. It is used for testing and debugging Android applications.

• Dalvik Debug Monitoring Service (DDMS):

The DDMS is used to monitor and control the Dalvik virtual machines on which the applications are being debugged.

• Android Asset Packaging Tool (AAPT): 

Builds the distributable Android package files ‘.apk’

• Android Debug Bridge(ADB):

Android Debug Bridge is a command-line debugging application distributed along with the SDK. It provides tools to browse the device, copy tools and forward ports for debugging.

What is Dalvik Virtual Machine?

Dalvik is the name of Android’s virtual machine. The Dalvik VM is an interpreter-only virtual machine that executes files in the Dalvik Executable (.dex) format, a format that is optimized for effective storage and memory-mappable executions. The virtual machine is register-based and can run classes compiled by Java language compiler that have been altered into its native format using the included ‘dx’ tool. The VM runs on top of Posix-compliant operating systems depending on it for performing threading and low level memory management functionalities. The Dalvik core class library is envisioned to provide a familiar development base for those used to programming with Java Standard Edition, but is geared explicitly for the needs of a small mobile device.

Why Learn Android Course?

Android is quick getting to be distinctly one of the greatest stages for developers today. There is a gigantic interest for gifted Android designers everywhere throughout the world. Most organizations over numerous areas are building Android Apps both for big business and retail items. Whether you are understudy or in the IT business, having Android Development aptitudes will help you take the following huge jump in your career.As a piece of this course, you'll build up your own particular portable applications under the direction of our master educators to give you a hands-on experience.This course is intended to help you turn into a top versatile application engineer.

Besant Technologies is a main Training and Placement organization in Chennai oversaw by IT sector with over 6 years involvement in driving MNC organizations.