The sections below provide instructions on how to download and install ADT into your Eclipse environment. If you encounter problems, see the Troubleshooting section.
ADT is a plugin for the Eclipse IDE. Before you can install or use ADT, you must have a compatible version of Eclipse installed on your development computer. Check the System Requirements document for a list of Eclipse versions that are compatible with the Android SDK.
http://www.eclipse.org/downloads/
The "Eclipse Classic" version is recommended. Otherwise, a Java or RCP version of Eclipse is recommended.
Additionally, before you can configure or use ADT, you must install the Android SDK starter package, as described in Downloading the SDK Starter Package. Specifically, you need to install a compatible version of the Android SDK Tools and at least one development platform. To simplify ADT setup, we recommend installing the Android SDK prior to installing ADT.
When your Eclipse and Android SDK environments are ready, continue with the ADT installation as described in the steps below.
Use the Update Manager feature of your Eclipse installation to install the latest revision of ADT on your development computer.
Assuming that you have a compatible version of the Eclipse IDE installed, as described in Preparing for Installation, above, follow these steps to download the ADT plugin and install it in your Eclipse environment.
https://dl-ssl.google.com/android/eclipse/
Note: If you have trouble acquiring the plugin, try using "http" in the Location URL, instead of "https" (https is preferred for security reasons).
Note: If you get a security warning saying that the authenticity or validity of the software can't be established, click OK.
After you've successfully downloaded the ADT as described above, the next step is to modify your ADT preferences in Eclipse to point to the Android SDK directory:
You may see a dialog asking whether you want to send usage statistics to Google. If so, make your choice and click Proceed. You cannot continue with this procedure until you click Proceed.
Done! If you haven't encountered any problems, then the installation is complete. If you're installing the Android SDK for the first time, return to Installing the SDK to complete your setup.