Android™ How to Program, Second Edition

B.8. Wrap-Up

In this appendix, you learned how to declare instance variables of a class to maintain data for each object of the class, and how to declare methods that operate on that data. You learned how to call a method to tell it to perform its task and how to pass information to methods as arguments. You learned the difference between a local variable of a method and an instance variable of a class and that only instance variables are initialized automatically. You also learned how to use a class’s constructor to specify the initial values for an object’s instance variables. Finally, you learned about floating-point numbers—how to store them with variables of primitive type double, how to input them with a Scanner object and how to format ...