gistfile1.java

 int day = datePicker.getDayOfMonth();
 int month = datePicker.getMonth() + 1; //plus 1 for making correct format
 int year = datePicker.getYear();
 long unixtime;
 
 String date = ""+day+month+year; //making String for SimpleDateFormat
 
 DateFormat dfm = new SimpleDateFormat("ddMMyyyy"); // instantiate SimpleDateFormat
 
 try{
  unixtime = dfm.parse(date).getTime(); //getting timestamp in milis
  unixtime=unixtime/1000L; // getting timestamp in unix time
  }
 catch (ParseException e){
  e.printStackTrace();
  }