public static void clearDatabase(Context context) { CategoryDataSource categoryDataSource = new CategoryDataSource(context); categoryDataSource.open(); categoryDataSource.clearCategory(); categoryDataSource.close(); MyListDataSource myListDataSource = new MyListDataSource(context); myListDataSource.open(); myListDataSource.clearMyList(); myListDataSource.close(); BookDataSource bookDataSource = new BookDataSource(context); bookDataSource.open(); bookDataSource.clearBook(); bookDataSource.close(); }