Xcode® 4

Chapter 8: Creating More Advanced Effects with Interface Builder

In This Chapter

Using File's Owner and First Responder Subclassing views and other objects Creating custom IB objects Creating views with static images Supporting non-English languages

Creating outlets and actions is a key step in application design with Interface Builder (IB). More complex applications require more advanced skills, which are discussed in this chapter.

Using File's Owner and First Responder

The top two objects in the list at the left of the IB interface are placeholders. They make it possible to link to objects that are outside the nib file.

Using File's Owner

File's Owner is a placeholder for the object that loaded the nib. It represents a different object in every nib. For example, in MainWindow.xib in the sample project in Chapter 7, File's Owner is a placeholder for the UIApplication object. In IBViewController.xib, File's Owner stands in for the IBViewController object.

This may seem complex the first time you encounter this feature, and it's certainly not an intuitive feature, because the true class/object name isn't displayed next to the icon.

However, if you select the File's Owner icon, you can check the class name in the Identity Inspector. It appears in the Class field at the top of the Utility Area.

Caution

These placeholders can seem confusing, but it's critical that you take time ...