Android : Subtract current row value with previous row in listview adapter

I´m using a cursor adapter and I want to set text on a textview subtracting the current row with the previous row of the listview, my code :

public class CustomCursorAdapter extends CursorAdapter {


@SuppressWarnings("deprecation")
public CustomCursorAdapter(Context context, Cursor c) {
    super(context, c);
    this.c = c;

}

@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
    // when the view will be created for first time,
    // we need to tell the adapters, how each item will look
    LayoutInflater inflater = LayoutInflater.from(parent.getContext());
    View retView = inflater.inflate(R.layout.list_row_main, parent, false);

    return retView;
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
double weight = cursor.getDouble(cursor
            .getColumnIndex(DbHelper.ENTRY_USER_WEIGHT));

     }
 }