This is an old question, that unfortunately even several years on doesn't have a good solution. I've just ported an app from iOS (Obj C) to Android. The biggest problem was not the back end code (for many/most folks, if you can code in Obj C you can code in Java) but porting the native interfaces. What Todd said above, UI layout is still a complete pain. In my experience, the fastest wat to develop a reliable UI that supports multiple formats etc is in good 'ol HTML.
