Popovers are very common within the iPad user interface but you were restricted to the design provided by Apple. With iOS 5 came a little known class called UIPopoverBackgroundView which allows you to provide a custom border and arrow for the popover.
Full tutorial with sample code here.
The ActionBar UI component has been introduced in Android 3.0 and above, and it seems to become the standard way to use tabs and context/action menus in Android applications.
You may also customize the ActionBar associated to your application in different ways through this great tutorial, however you might run into errors when you wish to override Tab item styles, to resolve this issue,
check this blog for a very straightforward solution. (due to private API issues)