Downloading Android SDK:

Android SDK provides you all the APIs necessary to develop and debug android applications,you can download ADT bundle,which Includes :

1. Eclipse + ADT plugin
2. Android SDK Tools
3. Android Platform-tools
4. The latest Android platform
5. The latest Android system image for the emulator

You can Download Complete ADT Bundle From the Link below:

Download ADT Bundle

Be Sure To select Your System Architecture i-e 32/64 bit before Downloading.

Or else If you already installed IDE then you can just download SDK available for particular OS,but sticking to majority,you can download Android SDK for Windows from the link below:

Download SDK For Windows

Integrating Android SDK

Now you are ready to open Eclipse, aren't you?

After clicking the icon following screen pops up:

This workspace launcher want you to select the directory you want,by default it stores in C:/users/xyz/workspace,though you can change it later on as well.

This should be followed by the people who have downloaded SDK separately,

 After opening Eclipse 

Follow the Following Steps:

• Click on the Help-tab and select Install new software

• click add-button and type ADT Plugin in the Name box
• copy and paste the following link into your Location-tab

http://dl-ssl.google.com/android/eclipse/

 

Now Accept the License Agreement and Install it,Now you will be noticing these two icons:

ASM is the Android SDK manager that let you Install all the latest APIs of Android,whereas AVD (Android Virtual Device) that is the Emulator used for Running Android applications by installing their .apk (Android application Extension).

Now one last step and you are ready to build your first ever Android app:

Go to Windows tab and Click on preferences.

 And you are DONE!