"AndroidBottomSheet" is an Android-library, which provides a bottom sheet as proposed by Android's Material design guidelines (see here for further details), which even works on pre-Lollipop devices. A bottom sheet is supposed to contain menu items, which can be clicked by the user. By default only a few items are shown, but by dragging the bottom sheet, it can be expanded to display all items.

On these Wiki pages the API of the library is discussed.