Limit tap gesture to scrollview and not the button placed upon it - iphone

Question

I have a scroll view and a button placed over it , When i add a tap gesture recognizer the button does not work. Is there any way of limiting the tap only to scroll view and not to the button, so that the button functions normally.
here is my code
UITapGestureRecognizer* tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapGesture:)];
tap.numberOfTapsRequired = 1;
tap.numberOfTouchesRequired = 1;
[scroll addGestureRecognizer:tap];
[tap release];
- (void)tapGesture:(UIGestureRecognizer*)gesture{
NSLog(#"scroll tapped");
}

Answer 1

If you do
tap.cancelsTouchesInView = NO;
It will allow button to be pressed. However taps will be detected along with the button press when you press a button. Do avoid this, you will have to subclass UIScrollView and implement the following method –
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
for ( UIView * subview in self.subviews ) {
UIView * hitView = [subview hitTest:point withEvent:event];
if ( hitView )
return hitView;
}
return [super hitTest:point withEvent:event];
}
Implementing the method above pass the touches to the scroll view's subviews.

Answer 2

There is no need to subclass Scrollview. Following code solves the problem easy way. The method gestureRecognizer:shouldReceiveTouch: does the trick.
UITapGestureRecognizer* tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapGesture:)];
tap.numberOfTapsRequired = 1;
tap.numberOfTouchesRequired = 1;
tap.delegate = self;
tap.cancelsTouchesInView = NO;
[scroll addGestureRecognizer:tap];
[tap release];
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {
if (scroll.superview != nil) {
if ([touch.view isKindOfClass:[UIButton class]])
{
return NO; // ignore the touch
}
}
return YES; // handle the touch
}
- (void)tapGesture:(UIGestureRecognizer*)gesture {
NSLog(#"scroll tapped");
}