Currently, Titanium's TabbedBar feature is iOS only. We should add support on Android for parity.
This would also be a solution for developers who want to see tabs at the bottom of the Android screen, such as how it works on iOS. The TabbedBar can be used in conjunction with a ScrollableView with scrolling disabled to have the same effect as a TabGroup.
Use the Google "design" support library's TabLayout class which only shows tabs.
Alternatively, use the Java TabHost class. The TabHost content area for the tabbed view can be set with a zero height so that only the tab bar is shown.
The iOS Ti.UI.TabbedGrouped is currently flagged deprecated. We should un-deprecate it and make the Ti.UI.iOS.TabbedGroup deprecated instead.
Google's material design guidelines suggests that you use a BottomNavigationView if the tabbed bar is shown at the bottom of the screen. It doesn't show an underline for tab selection and instead highlights the text and image. Unfortunately, this solution has a limit on how many tabs can be shown. It doesn't support horizontal scrolling. Perhaps this should be a style setting upon TabbedBar creation that can be implemented later?