Important: Support for the Android Developer Tools (ADT) in Eclipse has ended, per our announcement. You should migrate your app development projects to Android Studio as soon as possible. For more information on transitioning to Android Studio, see Migrating from Eclipse ADT.
Formerly the official IDE solution for Android development, Android Developer Tools (ADT) is a plugin for Eclipse that provides GUI-based access to many of the command-line SDK tools, along with a UI design tool for rapid prototyping, designing, and building of your app's user interface.
As with ADT, support for the tool for building from the command line has ended. Gradle is now the supported method of building Android apps.