Graphics Programs Reference
In-Depth Information
The first three ancestor-accessing properties of
UIViewController
are
naviga-
tionController
,
tabBarController
, and
splitViewController
. When a
view controller is sent one of these messages, it starts traversing the family tree until it
finds the appropriate type of view controller container. If there is no ancestor of the appro-
priate type, these methods return
nil
.
Additionally, every
UIViewController
has a
parentViewController
property.
This property holds the closest view controller ancestor in the family. Thus, it could return
a
UINavigationController
,
UITabBarController
, or a
UISplitViewController
depending on the makeup of the family tree.
Presenting-presenter relationships
The other kind of relationship is a presenting-presenter relationship, which occurs when a
view controller is presented modally. When a view controller is presented modally, its
view
is added
on top of
the view controller's
view
that presented it. This is different
than a view controller container, which intentionally keeps a spot open on its interface to
