I would say that we have a mixture of sample apps, but most are purely for teaching. For example, I have an app in the Touchscreen chapter that is meant to demonstrate how the events fire as fingers touch the screen, touch buttons, and drag. Definitely *not* a practical sample app. But in the Services chapter, there's an app that will convert a text
string from one language to another (using the Google Translate API in service calls). There's a drag and drop example on the Android Developer web site that is very simple and takes some shortcuts. I did a sample drag and drop application for chapter 31 that is more like a real app in that there are several objects that can be dragged, and I discovered some useful information that is shared in the book, information you don't get by running Android's sample app.
The main thing we tried to do in our samples was really demonstrate the concept of the chapter topic, to show how it really works, in as close to a real situation as we could for that particular feature. The reason they're not true practical applications is because they're missing all the other stuff that a truly practical app should have. We just couldn't build them all this way or the book would have 2000+ pages, and it would be harder to see how the one feature really works.
- dave
