Programming iOS 7, 4th Edition

Chapter 9. Popovers and Split Views

Popovers and split views are forms of interface that exist only on the iPad.

A popover (managed by a UIPopoverController) is a sort of secondary window or dialog: it displays a view layered on top of the main interface. It is usually associated, through a sort of arrow, with a view in the main interface — usually the button that the user tapped to summon the popover. In iOS 7, the popover dims out the rest of the screen, like a presented view whose presentation mode is UIModalPresentationPageSheet or UIModalPresentationFormSheet (see Chapter 6). It might be effectively modal, preventing the user from working in the rest of the interface; alternatively, it might vanish if the user taps outside it.

A popover, in effect, superimposes a roughly iPhone-sized screen on top of the iPad screen, and is useful in part precisely because it brings to the larger iPad the smaller, more lightweight flavor of the iPhone. For example, in my LinkSame app, both the settings view (where the user configures the game) and the help view (which describes how to play the game) are popovers (Figure 9-1). On the iPhone, both these views would occupy the entire screen; for each, we’d need a way to navigate to it, and then the user would have to return to the main interface afterward. But with the larger iPad screen, neither view is large enough, or important enough, to occupy the entire screen exclusively; the user can summon them without leaving the main interface. As popovers, ...