iOS App Development Portable Genius

Introducing Views, Nib Files, and Storyboards

So far, we’ve looked briefly at the code in an app. Now let’s look at views in more detail. Go back to the template you loaded earlier in the chapter. Open the Project navigator, if it isn’t already open. Click the ViewController-iPhone.xib file to load it into Interface Builder.

After a pause during which Interface Builder loads from disk (wait patiently if nothing seems to be happening), you’ll see the layout shown in Figure 4.8. In the figure, we’ve closed the Project navigator at the left to maximize the useful space.

Don’t forget that nib files have a .xib extension, not .nib, as you might expect. In fact, nib files used to have the .nib extension, but the extension was changed a few versions of Xcode ago. Technically, nib files now store object details in a format called XML (eXtensible Markup Language). The extension probably doesn’t stand for “XML nib file,” but it can be useful to pretend that it does.

4.8 Looking at the contents of a nib file.

Looking at nib files

In previous chapters, you learned that nib files are used to lay out and manage the UI (User Interface) of an app. UI design is a three-stage process:

1. Use Interface Builder in Xcode to lay out the content of each screen.

2. Add code to link “live” objects ...