Basic Building blocks Activities Services Broadcast Receivers and Content providers

Basic Building blocks
Android application is written in java program.But android phone tabs cant be execute the java file directly.Android os supporting devices like phone and Tabs contain  Dalvik Virtual machine.

Android program is mainly run on the Dalvik environment that is DALVIK VIRTUAL MACHINE.Dalvik Virtual Machine is  register based virtual machine,designed and written by Dan Borstin with the contribution of Google engineers.Features DVM is mainly optimized for low memory requirements and It designed to multiple VM instance to run at once,It also support for process isolation and Memmory management and Threading support.

Application Components

• Activities
• Services
• Content providers
• Broadcast receivers

       Activities

Activity represent a single screen with a user interface.Each of the screen are independent to each other.
To extend the features of the Activity we have to extend the class as follows:-


                 class Activity1 extends Activity implements OnClickListener

.Services

service also a componet that run in the Background to perform long running action.musuc player is the one of the example for Services.Service need to declard  in the androidmanifest.xml as follows:-


<service android:name="yourclasss"> </service>


and also mention the running services as  android:process=":process_description" attribute.

        Content providers

Content provider which manages a shared set of application of data.Shared pref reference and bundle mainly handle the Content provider services.

        Broadcast receivers

Broadcast component that respond to system wide broadcast announcent-for example during the low battery time we cant take the snap using camera function this is because the camera application get the system status through the Broadcast receiver

Dalvik virtual machine and apk Extention

Dalvik virtual machine

Android program is mainly run on the Dalvik environment that is DALVIK VIRTUAL MACHINE. Dalvik Virtual Machine is  register based virtual machine,designed and written by Dan Borstin with the contribution of Google engineers.
Features

• It is optimized for low memory requirements.
• It designed to multiple VM instance to run at once
• It also support for process isolation
• Memmory management and Threading support

A tool named dx, included in the Android SDK, transforms the Java Class files of Java classes compiled by a regular Java compiler into another class file format (the .dex format).

APK (Android application package)

APK is the file format used to distribute and install application software and middleware onto Google's Android operating system that is android devices like phone and tabs. To build an APK file, a program for Android is first compiled, and then all of its parts are packaged into one file that file which hold the apk extension. and also holds all of that program's code such as (.dex files), resources, assets, certificates, and manifest file. As is the case with many file formats, APK files can have any name needed, but must end with the four character, three letter extension, .apk.

Setting up development environment of Android in WINDOWS

Setting up development environment of Android in For Windows XP

Android

What is Android?

Context menu    It is long press menu.  view Contex menu code  List View in android    List view which provide List of content.  view List View code  List View + Context menu    List view and context menu  view List View code  Display Google Map in Android   Display the map in android phone  view map code There are different mobiles and computers operating systems like different models of computers and mobiles. Android is one of the operating systems using by the smart phones. Android is not simply an operating system rather hardware and programming languages are also use this Android Technology.

Android is a mobile software stack for mobile ,Tab devices. It also includes an operating system, middleware and key applications. TheAndroid SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language. Android was invented by an anonymous company but later on Google has taken its copyrights reserved and is now doing further development in this technology. It is Linux based technology that uses Unix as an operating system. Linux is the most recent technology in the field of communication and computing. It is therefore Android is demanded by most of the users to have it their operating system.  However it is also a fact that Google is offering an open choice for the users to modify and add any new application without even bring on the notice of Google. Anyone can upload a new application on the Android platform as App Store to either free or payable. These application uploads by the users can be easily download by the users and enjoy more features like additional games, interactive media and business plan.

Features Fast and easy application development Application framework(Eclipse IDE basecdevelopment) Dalvik virtual machine AVD managenent  Integrated browser Optimized graphics  SQLite for structured data storage Media support GSM Telephony  Bluetooth, EDGE, 3G, and WiFi Camera, GPS, compass, and accelerometer  Rich development environment,more editable and updateable Breaking down the application boundries

SDK

Installing the SDK

This page describes how to install the Android SDK and set up your development environment for the first time

Step 1. Preparing Your Development Computer


Before getting started with the Android SDK, take a moment to confirm that your development computer meets the System Requirements. In particular, you might need to install the JDK, if you don't have it already.
If you will be developing in Eclipse with the Android Development Tools (ADT) Plugin—the recommended path if you are new to Android—make sure that you have a suitable version of Eclipse installed on your computer as described in the System Requirements document. If you need to install Eclipse, you can download it from this location:

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

The "Eclipse Classic" version is recommended. Otherwise, a Java or RCP version of Eclipse is recommended.

Step 2. Downloading the SDK Starter Package

The SDK starter package is not a full development environment—it includes only the core SDK Tools, which you can use to download the rest of the SDK components (such as the latest Android platform).
If you haven't already, get the latest version of the SDK starter package from the SDK download page.
If you downloaded a .zip or .tgz package (instead of the SDK installer), unpack it to a safe location on your machine. By default, the SDK files are unpacked into a directory named android-sdk-<machine-platform>.
If you downloaded the Windows installer (.exe file), run it now and it will check whether the proper Java SE Development Kit (JDK) is installed (installing it, if necessary), then install the SDK Tools into a default location (which you can modify).
Make a note of the name and location of the SDK directory on your system—you will need to refer to the SDK directory later, when setting up the ADT plugin and when using the SDK tools from the command line.

Step 3. Installing the ADT Plugin for Eclipse

Android offers a custom plugin for the Eclipse IDE, called Android Development Tools (ADT), that is designed to give you a powerful, integrated environment in which to build Android applications. It extends the capabilites of Eclipse to let you quickly set up new Android projects, create an application UI, debug your applications using the Android SDK tools, and even export signed (or unsigned) APKs in order to distribute your application. In general, developing in Eclipse with ADT is a highly recommended approach and is the fastest way to get started with Android.
If you'd like to use ADT for developing Android applications, install it now. Read Installing the ADT Plugin for step-by-step installation instructions, then return here to continue the last step in setting up your Android SDK.
If you prefer to work in a different IDE, you do not need to install Eclipse or ADT. Instead, you can directly use the SDK tools to build and debug your application. The Introduction to Android application development outlines the major steps that you need to complete when developing in Eclipse or other IDEs.

Step 4. Adding Platforms and Other Components

The last step in setting up your SDK is using the Android SDK and AVD Manager (a tool included in the SDK starter package) to download essential SDK components into your development environment.
The SDK uses a modular structure that separates the major parts of the SDK—Android platform versions, add-ons, tools, samples, and documentation—into a set of separately installable components. The SDK starter package, which you've already downloaded, includes only a single component: the latest version of the SDK Tools. To develop an Android application, you also need to download at least one Android platform and the associated platform tools. You can add other components and platforms as well, which is highly recommended.
If you used the Windows installer, when you complete the installation wizard, it will launch the Android SDK and AVD Manager with a default set of platforms and other components selected for you to install. Simply click Install to accept the recommended set of components and install them. You can then skip to Step 5, but we recommend you first read the section about the Available Components to better understand the components available from the Android SDK and AVD Manager.
You can launch the Android SDK and AVD Manager in one of the following ways:

• From within Eclipse, select Window > Android SDK and AVD Manager.
• On Windows, double-click the SDK Manager.exe file at the root of the Android SDK directory.
• On Mac or Linux, open a terminal and navigate to the tools/ directory in the Android SDK, then execute:

  android

To download components, use the graphical UI of the Android SDK and AVD Manager to browse the SDK repository and select new or updated components (see figure 1). The Android SDK and AVD Manager installs the selected components in your SDK environment. For information about which components you should download, see Recommended Components.

Figure 1. The Android SDK and AVD Manager's Available Packages panel, which shows the SDK components that are available for you to download into your environment.

Available Components

By default, there are two repositories of components for your SDK: Android Repository and Third party Add-ons.
The Android Repository offers these types of components:

• SDK Tools — Contains tools for debugging and testing your application and other utility tools. These tools are installed with the Android SDK starter package and receive periodic updates. You can access these tools in the <sdk>/tools/ directory of your SDK. To learn more about them, see SDK Tools in the developer guide.
• SDK Platform-tools — Contains platform-dependent tools for developing and debugging your application. These tools support the latest features of the Android platform and are typically updated only when a new platform becomes available. You can access these tools in the <sdk>/platform-tools/ directory. To learn more about them, see Platform Tools in the developer guide.
• Android platforms — An SDK platform is available for every production Android platform deployable to Android-powered devices. Each SDK platform component includes a fully compliant Android library, system image, sample code, and emulator skins. To learn more about a specific platform, see the list of platforms that appears under the section "Downloadable SDK Components" on the left part of this page.
• USB Driver for Windows (Windows only) — Contains driver files that you can install on your Windows computer, so that you can run and debug your applications on an actual device. You do not need the USB driver unless you plan to debug your application on an actual Android-powered device. If you develop on Mac OS X or Linux, you do not need a special driver to debug your application on an Android-powered device. See Using Hardware Devices for more information about developing on a real device.
• Samples — Contains the sample code and apps available for each Android development platform. If you are just getting started with Android development, make sure to download the samples to your SDK.
• Documentation — Contains a local copy of the latest multiversion documentation for the Android framework API.

The Third party Add-ons provide components that allow you to create a development environment using a specific Android external library (such as the Google Maps library) or a customized (but fully compliant) Android system image. You can add additional Add-on repositories by clicking Add Add-on Site.