[This post is by Xavier Ducrohet, Android SDK Tech Lead. — Tim Bray]
However, as Dianne noted, this new API, which is part of Honeycomb, does not help developers whose applications target earlier versions of Android.
Today we’ve released a static library that exposes the same Fragments API (as well as the new LoaderManager and a few other classes) so that applications compatible with Android 1.6 or later can use fragments to create tablet-compatible user interfaces.
This library is available through the SDK Updater; it’s called “Android Compatibility package”.