Android™ How to Program, Second Edition

Class GradeBook

The GradeBook class declaration (Fig. B.1) contains a displayMessage method (lines 7–10) that displays a message on the screen. We’ll need to make an object of this class and call its method to execute line 9 and display the message.

The class declaration begins in line 4. The keyword public is an access modifier. For now, we’ll simply declare every class public. Every class declaration contains keyword class followed immediately by the class’s name. Every class’s body is enclosed in a pair of left and right braces, as in lines 5 and 11 of class GradeBook.

In Appendix A, each class we declared had one method named main. Class GradeBook also has one method—displayMessage (lines 7–10). Recall that main is a special method that’s ...