Split Views and Popovers

In Chapter 9, you spent a lot of time dealing with app navigation based on selections in table views, where each selection causes the top-level view, which fills the entire screen, to slide to the left and bring in the next view in the hierarchy, perhaps yet another table view. Plenty of iPhone and iPod touch apps work this way, both among Apple's own apps and third-party apps.

One typical example is Mail, which lets you drill down through servers and folders until you finally make your way to a message. Technically, this approach can work on the iPad as well, but it leads to a user interaction problem.

On a screen the size of the iPhone or iPod touch, having a screen-sized view slide away to reveal another screen-sized view works well. On a screen the size of the iPad, however, that same interaction feels a little wrong, a little exaggerated, and even a little overwhelming. In addition, consuming such a large display with a single table view is inefficient in most cases. As a result, you'll see that the built-in iPad apps do not actually behave that way. Instead, any drill-down navigation functionality, like that used in Mail, is relegated to a narrow column whose contents slide left or right as the user drills down or backs out. With the iPad in landscape mode, the navigation column is in a fixed position on the left, with the content o....split viewFigure 11–1