iPad Application Development For Dummies, 3rd Edition

What About the Model?

As this chapter shows (and as you’ll continue to discover), much of the functionality you need in an application is already in the frameworks.

But when it comes to the model objects — the things you build to actually hold the data and carry out the logic for your app — you’re on your own for the most part. In the RoadTrip app, for example, you’re going to need to create a Trip object that owns the data and logic and uses other objects to perform some of the actions it needs.

I talk about the model and model classes in more detail in Chapter 11. That’s where you’ll also find much more on implementing model objects.

You may find classes in the framework that help you get the nuts and bolts of the model working. But the actual content and specific functionality are up to you.

To implement the structure that enables me to include several destinations in the RoadTrip app, I need to have the data. I use property lists (XML files, in other words) to take care of that because they’re well suited for the job, and (more importantly) support for them is built in to the iPad frameworks. (For more on property lists, see Chapter 11.)

iOS now includes a UIDocument class for managing the data associated with a user’s documents. If you’re implementing a document-based application, ...