@Override
 public void onStart() {
   super.onStart();
   if (_dataStore.open()) {
     _activityCache = _dataStore.loadActivities();
     reSort();
     reAccumulate();
     reOrder();
     displayData();
   }
 }
 @Override
 protected void onStop() {
   _dataStore.close();
   super.onStop();
 }