To get a week number of a specific date use the Calendar.Week_of_year. To get the week numbers of a certain month run through each day of the month. You can do something like this, calling the function for a the specific month and year and String[] in return with the week number for each day.
public static String[] getWeeksOfMonth(int month, int year) { Calendar cal = Calendar.getInstance(); cal.set(Calendar.YEAR, year); cal.set(Calendar.MONTH, month); cal.set(Calendar.DAY_OF_MONTH, 1); int ndays = cal.getActualMaximum(Calendar.DAY_OF_MONTH); String weeks[] = new String[ndays]; for (int i = 0; i < ndays; i++) { weeks[i] = String.format("%d", cal.get(Calendar.WEEK_OF_YEAR)); cal.add(Calendar.DATE, 1); } return weeks; }
ndays is the numbers of days in the month from the getActualMaximum (28, 30 or 31). Then running through each day and returning the week string[]