To expand on the above answer a bit...
Moai is not really designed for this sort of thing. It's mostly about providing a fairly low-level framework for graphics/games that can be targeted to different devices. This works great if your game has a sui-generis interface with it's own buttons etc but works less well the minute you start wanting to use standard UI controls on whichever platform you happen to be running on.
One could build a UI-library on top of Moai and there are people doing that but but it's not something that's wrapped up in Moai itself.