From reading the UIGestureRecognizer Class Reference it is implied that the API will handle the prioritizing of touches and gesture controls for you, making sure that your touchesBegan and related methods are not called on the view unless the gesture recognizers have first failed:
A window delivers touch events to a gesture recognizer before it delivers them to the hit-tested view attached to the gesture recognizer. Generally, if a gesture recognizer analyzes the stream of touches in a multi-touch sequence and does not recognize its gesture, the view receives the full complement of touches. If a gesture recognizer recognizes its gesture, the remaining touches for the view are cancelled.
I have added a swipe gesture to my view, and it is working. Via some logging, when I do a single swipe, the method reports as such. However, my touchesBegan method is also reporting via its log, despite that the touchesCancelled method is, as expected, also receiving a message.
I want, and expect, the gesture recognize to prevent touchesBegan or touchesMoved from being called.
So my question is: for the gesture recognizer to in fact delay touches based on its state, is there additional setup necessary? The docs do not suggest anything else as necessary.
My setup is simply:
swipeUpTwoFinger=[[[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(doubleSwipeUp:)]autorelease];
swipeUpTwoFinger.direction=UISwipeGestureRecognizerDirectionUp;
swipeUpTwoFinger.numberOfTouchesRequired=2;
[self addGestureRecognizer:swipeUpTwoFinger];
I have also tried this test to make sure a recognizer has failed before processing with touchesBegan (this test should not be necessary if you believe what the docs say above) but the touchesBegan is still processing the log line after this test:
if (swipeUpTwoFinger.state==UIGestureRecognizerStateFailed)
Best Answer
It sounds like you need:
swipeUpTwoFinger.delaysTouchesBegan = YES;