Coding the database class
Here we will put into practice everything we have learned so far and finish coding the Age Database app. Before our Fragment classes from the previous section can interact with a shared database, we need a class to handle interaction with, and the creation of, the database.
We will create a class that manages our database by using the SQLiteOpenHelper class. It will also define some final strings to represent the names of the table and its columns. Furthermore, it will supply a bunch of helper methods we can call to perform all the necessary queries. Where necessary, these helper methods will return a Cursor object that we can use to show the data we have retrieved. It would be trivial, then, to add new helper methods, should our app need to evolve.
Create a new class called DataManager and add the following member variables:
import android.database.sqlite.SQLiteDatabase;
public class DataManager {
// This is the actual database...