Android™ How to Program, Second Edition

Method getAllContacts

Method getAllContacts (Fig. 8.55) uses SqLiteDatabase’s query method (lines 83–84) to retrieve a Cursor that provides access to the IDs and names of all the contacts in the database. The arguments are:

• the name of the table to query.

• a String array of the column names to return (the _id and name columns here)—null returns all columns in the table, which is generally a poor programming practice, because to conserve memory, processor time and battery power, you should obtain only the data you need.

• a SQL WHERE clause (without the keyword WHERE), or null to return all rows.

• a String array of arguments to be substituted into the WHERE clause wherever ? is used as a placeholder for an argument value, or null if there ...