java Android get date before 7 days (one week) Stack Overflow

Parse the date:

Date myDate = dateFormat.parse(dateString);

And then either figure out how many milliseconds you need to subtract:

Date newDate =newDate(myDate.getTime()-604800000L);// 7 * 24 * 60 * 60 * 1000

Or use the API provided by the java.util.Calendar class:

Calendar calendar =Calendar.getInstance();
calendar.setTime(myDate);
calendar.add(Calendar.DAY_OF_YEAR,-7);Date newDate = calendar.getTime();

Then, if you need to, convert it back to a String:

String date = dateFormat.format(newDate);