Coding the PongActivity class
In this project, as discussed previously, we will have multiple classes. Four to be exact. The Activity class provided by the Android API is the class that interacts with the operating system. We have already seen how the operating system interacts with onCreate when the player clicks the app icon to start an app (or our game). Furthermore, we have seen how the operating system calls the onTouchEvent method when the user interacts with the screen, giving us the opportunity to make our game respond appropriately.
As this game is more complicated and needs to respond in real time, it is necessary to use a slightly more in-depth structure. At first, this seems like a complication, but in the long run, it makes our code simpler and easier to manage.
Rather than having a class called Pong (analogous to SubHunter) that does everything, we now have a class that just handles the startup and shutdown of our game, as well as helping a bit with initialization...