Android Development Tools (ADT) is a plugin for the Eclipse IDE that is designed to give you a powerful, integrated environment in which to build Android applications.
ADT extends the capabilities of Eclipse to let you quickly set up new Android projects, create an application UI, add components based on the Android Framework API, debug your applications using the Android SDK tools, and even export signed (or unsigned) .apk files in order to distribute your application.
Developing in Eclipse with ADT is highly recommended and is the fastest way to get started. With the guided project setup it provides, as well as tools integration, custom XML editors, and debug ouput pane, ADT gives you an incredible boost in developing Android applications.
This document provides step-by-step instructions on how to download the ADT plugin and install it into your Eclipse development environment. Note that before you can install or use ADT, you must have compatible versions of both the Eclipse IDE and the Android SDK installed. For details, make sure to read Installing the ADT Plugin, below.
If you are already using ADT, this document also provides instructions on how to update ADT to the latest version or how to uninstall it, if necessary.