Inheritance mini-app

We have looked at the way we can create hierarchies of classes to model the system that fits our game. So, let's try out some simple code that uses inheritance. The completed code is in the chapter 8 folder of the code download. It is called InheritanceExample.

Create a new project called Inheritance and use the Empty Activity template. Create three new classes in the usual way. Name one AlienShip, another Fighter, and the last one Bomber.

Next is the code for the AlienShip class. It is very similar to our previous demo AlienShip class. The difference is that the constructor now takes an int parameter that it uses to set the shield strength.

The constructor also outputs a message to the logcat window, so we can see when it is being used. The AlienShip class also has a new method, fireWeapon, which is declared abstract. This guarantees that any class that subclasses AlienShip must implement its own version of fireWeapon. Notice the class has the abstract...