iOS: Why touchesBegan has some delay in some specific area in UIView

Question

I'm making a custom keyboard and I'm in a really weird situation.

I've noticed that when I catch the event touchesBegan at the rear left (about 20 pixels) of the UIView (inputView), I'll have some delay in here. Any action I do in touchesBegan will be perform slower than other area.

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
self.keypop.hidden = false
}

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
{
self.keypop.hidden = true
}

And this trouble affects my app's performance. In this example, I will not see the keypop appears when I touched on the rear left because self.keypop.hidden was delayed in showing up.

I don't know why, or is this an error from iOS 9? I've been stuck on this trouble for a week.

Answer 1

The answer here seems to have fixed the same issue in our keyboard:

UISystemGateGestureRecognizer and delayed taps near bottom of screen

With the following code:

override func viewDidAppear(animated: Bool) {
    let window = view.window!
    let gr0 = window.gestureRecognizers![0] as UIGestureRecognizer
    let gr1 = window.gestureRecognizers![1] as UIGestureRecognizer
    gr0.delaysTouchesBegan = false
    gr1.delaysTouchesBegan = false
}

Answer 2

In my situation I was using touchBegan in a CollectionView and it was delaying touches when I tap Its worked with me by simply added this code

In Swift,

self.collectionView.delaysContentTouches = false
/*delaysContentTouches applies to all UIScrollView instances.*/