An example of implementing BottomAppBar: Material Components for Android based on this article on meduim.
backgroundTint is the attribute for setting BottomAppBar background color.
fabAlignmentMode attribute determines the position of the FAB either being at the center or at the end of BottomAppBar. Below screenshot shows FAB alignment when fabAlignmentMode is set to end.
fabCradleDiameter specifies the diameter of the cradle containing the FAB.
fabCradleRoundedCornerRadius specifies the radius of the corner curve at the meeting point of cradle and horizontal part of the BottomAppBar.
fabCradleVerticalOffset specifies the offset of the cradle from the bottom.