If you have no experience with Android UI but you know a little Java already, maybe this is something for you:
SimpleUi ( https://github.com/bitstars/SimpleUi )
The generated UI (code below):
The complete code to create this Android UI:
I use it in real applications, not only for fast prototyping or dialogs and its well tested over the years. The concept is based on the model view control principle and for most common scenarios there are ready to use components which automatically look correct on any device. I don't say it should be used for any UI (e.g. listviews should be done by hand) but for most usecases this should be quite handy ;) Oh and feel free to fork it and improve it further if you want
