Question

first UIApplication ,or Control ?

before I think the first is UIApplication.
but now I think maybe the first is Control .

the Basis is below：

http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIControl_Class/Reference/Reference.html#//apple_ref/occ/cl/UIControl

sendAction:to:forEvent:
In response to a given event, forwards an action message to the application object for dispatching to a target.

this cause me to trust the UIControl first get the Control Event before application .

Answer 1

The UIEvent class and the UIControlEvent constants are not the same thing. An event object encapsulates information about a touch sequence, a control event is a UIControl’s interpretation of a particular touch sequence within its bounds.

The sequence is:

1. Operating system receives and delivers UIEvent object to UIApplication.
2. [UIApplication sendEvent:] delivers the event to the
   key window
3. [UIWindow sendEvent:] delivers the (touch) event to the
   hit tested view

4. [UIView touches...] event handling methods called

   The UIControl object interprets touches and determines the UIControlEvent constant if any

5. [UIControl sendAction:to:forEvent:] is called once or more times

6. [UIApplication sendAction:to:from:forEvent:] is called
7. The action is performed on the target

So the UIEvent starts with UIApplication, but the UIControlEvent starts with the UIControl.