private void refreshShiftsPreferences() {
   // Create default shifts if preferences are empty
   SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
   mCustomShifts = prefs.getString("shifts", "");
   if (mCustomShifts.equals("")) {
     SharedPreferences.Editor editor1 = prefs.edit();
     editor1.putString("shifts", DEFAULT_SHIFTS);
     editor1.commit();
     mCustomShifts = DEFAULT_SHIFTS;
   }
   mShiftList = Shift.parse(mCustomShifts);
   mShiftTable = new Hashtable<String, Shift>();
   changeItems = new CharSequence[mShiftList.size()];
   int i = 0;
   dialogItems = new ArrayList<String>();
   String itemRow;
   for (Shift s : mShiftList) {
     itemRow = s.getAbbreviation() + " (" + s.getName() + ")";
     changeItems[i++] = itemRow;
     dialogItems.add(itemRow);
     mShiftTable.put(s.getAbbreviation(), s);
   }
   dialogItems.add(getString(R.string.overtime_set));
   dialogItems.add(getString(R.string.daily_notes));
 }