Graphics Programs Reference
In-Depth Information
trolEvents:
to itself. This method looks at all of the target-action pairs the control
has, and if any of them are registered for the control event passed as the argument, those
targets are sent an action message.
However, a control never sends a message directly to its targets. Instead, it routes these
messages through the
UIApplication
object. Why not have controls send the action
messages directly to the targets? Controls can also have
nil
-targeted actions. If a
UIControl
's target is
nil
, the
UIApplication
finds the
first responder
of its
UIWindow
and sends the action message to it.
