来自datepicker对话框的日期没有在弹出的android的textview中设置

My question is in onDateSet method, how do i retrieve the selected date from the datepicker dialog on my textview field which is an activity embedded on popup. I get the nullpointer exception for: ((TextView) getActivity().findViewById(R.id.spinner_date)).setText("Date"+year);My question is in onDateSet method, how do i re