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== The Target-Action pattern, IBOutlets and IBActions ==

When you create an iOS 5 iPad app you will typically design the user interface (the view) using the Interface Builder tool and write the view controller and model code in Objective-C using the Xcode code editor. The previous section looked briefly at how the view controller interacts with the model. In this section we will look at how the view created in Interface Builder and our view controller code interact with each other.

When a user interacts with objects in the view, for example touching and releasing a button control, an event is triggered (in this case the event is called a Touch Up Inside event). The purpose of the Target-Action pattern is to allow you to specify what happens when such events are triggered. In other words, this is how you connect the objects in the user interface you have designed in the Interface Builder tool to the back end Objective-C code you have written in the Xcode environment. Specifically, this allows you to define which method of which controller object gets called when a user interacts in a certain way with a view object.