@Override
        public void onBindViewHolder(MonthViewHolder holder, int position) {
            final int year = getYearForPosition(position);
            final int month = getMonthForPosition(position);
            holder.bind(year, month, position == selectedPosition, position < selectedPosition);
        }
Color when month is before the current selected month
library/src/main/java/com/github/badoualy/datepicker/MonthView.java