@Override
        public void onChanged() {
            super.onChanged();
            if (mAdapter != null && mAdapter.hasStableIds())
                confirmCheckedPositionsById(mAdapter.getItemCount());
        }
The ItemChoiceManager class keeps track of which positions have been selected.  Note that it
doesn't take advantage of new adapter features to track changes in the underlying data.
app/src/main/java/com/example/android/sunshine/app/ItemChoiceManager.java