Answer Count:
1
Not here yet.
As of Android Honeycomb, you can't. Despite the feature seeming incredibly rudimentary, surprisingly enough there is no undo feature in Android. The lack of the feature is much maligned and has been brought to the attention of the Android developers. If you'd like to add your name to the list of folks that want an undo feature in Android, check out the link below.
http://code.google.com/p/android/issues/detail?id=13329&q=undo








As of Jelly Bean, there is
As of Jelly Bean, there is still no undo feature available in Android.