Recipe Creating a Separate Database Package

A good modular structure to classes is essential for more complicated Android projects. Here, the database class is put in its own package so it is easy to reuse. This package contains three classes: MyDB, MyDBhelper, and Constants.

The MyDB class is shown in Listing 9.9. It contains a SQLiteDatabase instance and a MyDBhelper class (described in the following) with the methods that follow:

■ MyDB()—Initializes a MyDBhelper instance (the constructor).

■ open()—Initializes a SQLiteDatabase instance using the MyDBhelper.This opens a writeable database connection. If SQLite throws any exception, it tries to get a readable database instead.

■ close()—Closes the database connection.

■ insertdiary()—Saves a diary entry to the database as name-value pairs in a ContentValues instance, and then passes the data to the SQLitedatabase instance to do an insert.

■ getdiaries()—Reads the diary entries from the database, saves them in a Cursor class, and returns it from the method.

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