I’ve been fucked by a touching delay for several days.
By touching delay, I mean: I have a UICollectionView subviewing to some views, and when I selected a cell of the UICollectionView, it didn’t go to the didSelectItemAtIndexPath delegate method. After hundreds of clicking cells, I’ve noticed that only if I long press a cell, it goes to didSelectItemAtIndexPath. I asserted that my select-touching was delayed by something.
It turned out that it is a UITapGestureRecognizer that causes the delay. The UITapGestureRecognizer was assigned to the UICollectionView’s some superview, in order to dismiss keyboard when user touch anywhere within the screen. So when a touch comes, the UITapGestureRecognizer would block the touch temporarily until it decides whether this touch should be handled by it(UITapGestureRecognizer). Only after the touch is released by UITapGestureRecognizer, it goes to delegate. Deciding takes 1 sec estimated, which leads to a delay.
How I get rid of this touching delay is add a single UIGestureRecognizerDelegate method:
/* This delegate decides whether the gesture recognizer would see this touch. */
func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
/* Get the view that the touch landed on. */
if let touchView = touch.view {
/* If the landed view is a cell of my UICollectionView, forbid the UIGestureRecognizer receive this touch. */
if (touchView.frame.size.height + touchView.frame.size.width) == 130 {
return false
}
}
/* Otherwise let UIGestureRecognizer handle the touch. */
return true
}
Remember assign delegate to your UITapGestureRecognizer, and this might also works for getting rid of touching delay caused by all kinds of UIGestreRecognizer (Tap, Pan, Pinch, Swipe, etc).