var style: Int
Style of the popup menu.
For dark themes you should use R.style.Widget_MPM_Menu_Dark.
Setting this to 0 will make the popup use the default style resolved based on context
passed to MaterialPopupMenu.show function. You can customize that default style by defining
R.attr.materialPopupMenuStyle in your theme style.
NOTE: make sure that all of the attributes that are declared in R.style.Widget_MPM_Menu are also declared in your style.