iPhone - gesture recognizers fighting each other - iphone

Question

I have added two gesture recognizers to a view. One will handle the view drag and the other the double tap. Something like
UITapGestureRecognizer *doubleTap =
[[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(deleteThisView)];
[doubleTap setDelegate:self];
[doubleTap setCancelsTouchesInView:YES];
[doubleTap setNumberOfTapsRequired:1];
[base addGestureRecognizer:doubleTap];
[doubleTap release];
UIPanGestureRecognizer *panGesture = nil;
panGesture = [[UIPanGestureRecognizer alloc]
initWithTarget:self action:#selector(drag:)];
[panGesture setMaximumNumberOfTouches:1];
[panGesture setDelegate:self];
[base addGestureRecognizer:panGesture];
[panGesture release];
The problem is this: as the view can move, the double tap is somehow difficult to obtain, because the view can slide one hair to one side or the other and iOS will not recognize it as double tap, and instead will see it as two moves and the drag method will run twice.
I am not seeing how this can be done. Any clues?
thanks

Answer 1

There's a delegate method that will tell the central gesture code that two recognizers might be going at the same time:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
if (gestureRecognizer==_panRecognizer && otherGestureRecognizer==_swipeRecognizer)
return YES;
if (gestureRecognizer==_swipeRecognizer && otherGestureRecognizer==_panRecognizer)
return YES;
return NO;
}
Maybe you can try something like that.

Answer 2

Here is Vagrant's answer in swift:
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWithGestureRecognizer otherGestureRecognizer: UIGestureRecognizer) -> Bool {
if gestureRecognizer == panRecognizer && otherGestureRecognizer == swipeRecognizer {
return true
}
if gestureRecognizer == swipeRecognizer && otherGestureRecognizer == panRecognizer {
return true
}
return false
}
Don't forget to implement the delegate protocol and set your gestures' delegates to self (I forgot this initially).