require(toFail) not working for PanGestureRecognizer and PageViewController - ios

Question

Here's the problem I'm having:
I have a PageViewController that navigates between 4 views horizontally and a PanGestureRecognizer on a UIView that brings it up and down vertically. The issue is that the UIView can be panned up, but then it is stuck there. The user can only swipe horizontally with the PageViewController.
The goal:
Be able to pan the UIView up and down AND swipe left and right on the PageViewController. Basically, make the UIView not get stuck on screen.
This is what I have now:
I have a PanGestureRecognizer function in the UIView file that looks
like this:
func handlePan(recognizer: UIPanGestureRecognizer) {
let vel = recognizer.velocity(in: self)
print("HANDLING PAN")
switch recognizer.state {
case .began:
if vel.y < 0 && !scanIsUp {
animator = UIViewPropertyAnimator(duration: 1, curve: .easeOut, animations: {
self.frame = self.frame.offsetBy(dx: 0, dy: -603)
})
scanIsUp = true
isScanVisible = true
} else if vel.y > 0 && scanIsUp {
print("vel.y hehehe")
animator = UIViewPropertyAnimator(duration: 1, curve: .easeOut, animations: {
self.frame = self.frame.offsetBy(dx: 0, dy: 603)
})
scanIsUp = false
isScanVisible = false
}
animator?.pauseAnimation()
print("paused?")
case .changed:
let translation = recognizer.translation(in: backgroundImage)
if vel.y < 0 && scanIsUp {
animator?.fractionComplete = translation.y / -603
} else if vel.y > 0 && !scanIsUp {
print("vel.y hehehe pt 2")
animator?.fractionComplete = translation.y / 603
}
case .ended:
animator?.continueAnimation(withTimingParameters: nil, durationFactor: 0)
case .possible: break
default: break
}
}
I also have an array of gestureRecognizers that control the PageViewController. I cycle through them and require them to fail so that the user can pan the UIView up and down like this:
if #available(iOS 10.0, *) {
self.panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(PFScan.handlePan))
self.panGestureRecognizer!.maximumNumberOfTouches = 1
self.panGestureRecognizer!.cancelsTouchesInView = false
self.addGestureRecognizer(self.panGestureRecognizer!)
for recognizer in self.scrollViewGestureRecognizers {
recognizer.require(toFail: panGestureRecognizer!)
}
}
Finally, I initialize the UIView on the main view controller part of the PageViewController like this:
func setUpScanPage(scrollViewGestureRecognizers: [UIGestureRecognizer]) {
scanPage = PFScan(scrollViewGestureRecognizers: scrollViewGestureRecognizers)
self.view.addSubview(scanPage)
}
Does anyone know why the UIView gets stuck?? I have tried everything I know of. Any help would be immensely appreciated.
Thanks a ton in advanced. Cheers,
Theo