On this page concerning installation, it currently says:
You can choose downloading ADT Bundle package that in addition to Android SDK Tools includes Eclipse + ADT + NDK/CDT plugins, Android Platform-tools, the latest Android platform and the latest Android system image for the emulator - this is the best choice for those who is setting up Android development environment the first time!
But this is no longer a supported development environment, as indicated here.
How do required changes to the OpenCV documentation get in the queue?