Android

Android is a operation system used for mobile ( Google’s ) and it includes software components, application and key application  (Menu key or Application key is a key found on Microsoft Windows-oriented computer ). It is java based object oriented application frame work  and it allows developers to write manage code in the java,

Android programmed in C (core), C++ (for third party libraries), Java  and it is free open source application , their latest version called  Froyo 2.2

Nowadays developers using widely because development tools and platform are free to download ( * Charging for  distribute application to market ), it is an opean-source platform Linux kernel and open ource libraries. ndroid developers are not required to sign an NDA and are encouraged to collaborate and share source code with each other. Google’s Android Market, and developers are free to distribute their applications through other distribution channels as well, and it support multi platform,  and nowdays all are supporting Android support .

How to install Android SDK

Before getting started with the Android SDK, we need JDK in our system  you can download that from bellow link

http://java.sun.com/javase/downloads/index.jsp

I thought this application can develop in Eclipse with Android Development Tool ( ADT ) please download eclipse  from bellow link – Download   ”Eclipse Classic”

http://www.eclipse.org/downloads/

you can install android SDK from bellow link
http://developer.android.com/sdk/index.html ( * I am using windows so downloaded windows  package )

You can find installation steps on Android website
http://developer.android.com/sdk/installing.html#components

Creating an application

The /src folder
It contains all of our custom source code, grouped into packages.

The /gen folder
This folder include file R.java file and all automatically generated AIDL java files ,
Better say code generated for all the resources , we can access layouts and controls defined within our code .

The assets/ folder
This is empty. You can use it to store raw asset files.

The res/ folder
A folder for your application resources, such as drawable files, layout files, string values, etc.To view the XML for the layout on screen, click the main.xml tab.Values are where you define (in XML) your globally used colors, dimensions, strings and styles. The strings.xml file allows you to add and edit values for your project.

AndroidManifest.xml
Every application must have an AndroidManifest.xml file (with precisely that name) in its root directory.The manifest presents essential information about the application to the Android system,You will notice that the Name field doesn’t actually contain the name text, but “@string/app_name” instead. This is a string reference and can be used anytime a string is expected. The actual string text is then defined in one of the XML files found under the res/values folder. The app creation wizard generated a file there called strings.xml

default.properties
This file contains project settings, such as the build target. This files is integral to the project, as such, it should be maintained in a Source Revision Control system. It should never be edited manually — to edit project properties, right-click the project folder and select “Properties”.

Android Stimulator Output

• Application framework enabling reuse and replacement of components
• Dalvik virtual machine optimized for mobile devices
• Integrated browser based on the open source WebKit engine
  Optimized graphics powered by a custom 2D graphics library; 3D graphics based on the OpenGL ES 1.0 specification (hardware acceleration optional)
• SQLite for structured data storage
• Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)
• GSM Telephony (hardware dependent)
• Bluetooth, EDGE, 3G, and WiFi (hardware dependent)
• Camera, GPS, compass, and accelerometer (hardware dependent)Rich development environment including a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE

Android Architecture

Android Architecture

Courtesy – developer.android.com