AndroidAPPLICATION DEVELOPMENTBY ABHIANDROID

Table of contents• About Android• History and Version• Software Stack• Core Building Blocks• Android Emulator• Installing software• Setup Eclipse• Dalvik VM• AndroidManifest.xml• R.java• Questions & Answers

About Android• Android is a software package and linux based operating

system for mobile devices such as tablet computers and smartphones.• It is developed by Google and later the OHA (Open Handset

Alliance). Java language is mainly used to write the android code even though other languages can be used.• The goal of android project is to create a successful real-world

product that improves the mobile experience for end users.• It is open-source.• Anyone can customize the Android Platform.• There are a lot of mobile applications that can be chosen by

the consumer.• It provides many interesting features like weather details,

opening screen, live RSS (Really Simple Syndication) feeds etc.

Android History• Initially, Andy Rubin founded Android Incorporation in Palo

Alto, California, United States in October, 2003.• In 17th August 2005, Google acquired android Incorporation.

Since then, it is in the subsidiary of Google Incorporation.• The key employees of Android Incorporation are Andy Rubin,

Rich Miner, Chris White and Nick Sears.• Originally intended for camera but shifted to smart phones

later because of low market for camera only.• Android is the nick name of Andy Rubin given by coworkers

because of his love to robots.• In 2007, Google announces the development of android OS.• In 2008, HTC launched the first android mobile.

Android versionsVersion Code name API Level

1.5 Cupcake 31.6 Donut 42.1 Eclair 72.2 Froyo 82.3 Gingerbread 9 and 103.1 and 3.3 Honeycomb 12 and 134.0 Ice Cream Sandwitch 154.1, 4.2 and 4.3 Jelly Bean 16, 17 and 184.4 KitKat 195.0 Lollipop 21

Android Software Stack• linux kernel• native libraries (middleware),• Android Runtime• Application Framework• Applications

Android Core Building Blocks• The core building blocks or fundamental components

of android are:• activities• Views• Intents• Services• content providers• Fragments• AndroidManifest.xml.

Android Emulator• Android Emulator is used to run, debug and test the

android application. If you don't have the real device, it can be the best way to run, debug and test the application.• It uses an open source processor emulator technology

called QEMU.• The emulator tool enables you to start the emulator from

the command line.• In case of Eclipse IDE, you can create AVD by Window

menu > AVD Manager > New.• In the given image, you can see the android emulator, it

displays the output of the hello android example.

Installing software• Android supports java, c++, c# etc. language to

develop android applications. Java is the officially supported language for android. All the android examples of this site is developed using Java language and Eclipse IDE.• Here, we are going to tell you, the required softwares

to develop android applications using Eclipse IDE.• There are two ways to install android: by ADT Bundle,

by Setup Eclipse Manually.

Setup Eclipse• Install the JDK• Download and install the Eclipse for developing

android application• Download and Install the android SDK• Intall the ADT plugin for eclipse• Configure the ADT plugin• Create the AVD• Create the hello android application

Dalvik Virtual Machine | DVM• The Dalvik Virtual Machine (DVM) is an android virtual

machine optimized for mobile devices. It optimizes the virtual machine for memory, battery life and performance.• The Dex compiler converts the class files into the .dex file

that run on the Dalvik VM. Multiple class files are converted into one dex file. • The javac tool compiles the java source file into the class

file.• The dx tool takes all the class files of your application and

generates a single .dex file. It is a platform-specific tool.• The Android Assets Packaging Tool (aapt) handles the

packaging process.

Dalvik Virtual Machine | DVM

AndroidManifest.xml• The AndroidManifest.xml file contains information of your

package, including components of the application such as activities, services, broadcast receivers, content providers etc.• It is responsible to protect the application to access any

protected parts by providing the permissions.• It also declares the android api that the application is going to

use.• It lists the instrumentation classes. The instrumentation

classes provides profiling and other information's. These information's are removed just before the application is published etc.• This is the required xml file for all the android application and

located inside the root directory.

R.Java• Android R.java is an auto-generated file by aapt

(Android Asset Packaging Tool) that contains resource IDs for all the resources of res/ directory.• If you create any component in the activity_main.xml

file, id for the corresponding component is automatically created in this file. This id can be used in the activity source file to perform any action on the component.• If you delete R.jar file, android creates it

automatically.

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