Detect touch down & touch up in a view containing UIControls - iphone

Question

I'm trying to detect when a user touches down and up in a view. The view contains some buttons and other UIKit controls. I would like to detect these touch events but not consume them.
I've tried two approaches, but neither has been sufficient:
First I added a transparent overlay overriding -touchesBegan:withEvent: and -touchesEnded:withEvent: and forward the event to the next responder with
[self.nextResponder touchesBegan:touches withEvent:event]
However, it seems that UIKit objects ignore all forwarded events.
Next, I tried overriding -pointInside:withEvent: and -hitTest:withEvent: . This worked great to detect touch down events, but pointInside:: and hitTest:: are not called on touch up (i.e. [[[event allTouches] anyObject] phase] is never equal to UITouchPhaseEnded ).
What's the best way to detect both touch down and touch up events without disturbing interaction with the underlying UIControls?

Answer 1

according to the Event Handling Guide for iOS
you have 3 options:
1) subclassing UIWindow to override sendEvent:
2) using an overlay view
3) designing so that you don't have to do that... so really more like 2 options.
Here is a simplification of apples example, using UIWindow subclass;
1) change the class of your window in the NIB to your subclass of UIWindow.
2) put this method in the .m file.
- (void)sendEvent:(UIEvent *)event
{
NSSet * allTouches = [event allTouches];
NSMutableSet *began = nil;
NSMutableSet *moved = nil;
NSMutableSet *ended = nil;
NSMutableSet *cancelled = nil;
// sort the touches by phase so we can handle them similarly to normal event dispatch
for(UITouch *touch in allTouches) {
switch ([touch phase]) {
case UITouchPhaseBegan:
if (!began) began = [NSMutableSet set];
[began addObject:touch];
break;
case UITouchPhaseMoved:
if (!moved) moved = [NSMutableSet set];
[moved addObject:touch];
break;
case UITouchPhaseEnded:
if (!ended) ended = [NSMutableSet set];
[ended addObject:touch];
break;
case UITouchPhaseCancelled:
if (!cancelled) cancelled = [NSMutableSet set];
[cancelled addObject:touch];
break;
default:
break;
}
// call our methods to handle the touches
if (began)
{
NSLog(#"the following touches began: %#", began);
};
if (moved)
{
NSLog(#"the following touches were moved: %#", moved);
};
if (ended)
{
NSLog(#"the following touches were ended: %#", ended);
};
if (cancelled)
{
NSLog(#"the following touches were cancelled: %#", cancelled);
};
}
[super sendEvent:event];
}
It has way too much output, but you will get the idea... and can make your logic fit where you want it to.