UIScrollView in tvOS - swift

Question

I have a view hierarchy similar to the one in the image below (blue is the visible part of the scene):
So I have a UIScrollView with a lot of elements, out of which I am only showing the two button since they are relevant to the question. The first button is visible when the app is run, whereas the other one is positioned outside of the initially visible area. The first button is also the preferredFocusedView.
Now I am changing focus between the two buttons using a UIFocusGuide, and this works (checked it in didUpdateFocusInContext:). However, my scroll view does not scroll down when Button2 gets focused.
The scroll view is pinned to superview and I give it an appropriate content size in viewDidLoad of my view controller.
Any ideas how to get the scroll view to scroll?

Answer 1

Take a look at UIScrollView.panGestureRecognizer.allowedTouchTypes. It is an array of NSNumber with values based on UITouchType or UITouch.TouchType (depending on language version). By default allowedTouchTypes contains 2 values - direct and stylus. It means that your UIScrollView instance will not response to signals from remote control. Add the following line to fix it:
Swift 4
self.scrollView.panGestureRecognizer.allowedTouchTypes = [NSNumber(value: UITouchType.indirect.rawValue)]
Swift 4.2 & 5
self.scrollView.panGestureRecognizer.allowedTouchTypes = [NSNumber(value: UITouch.TouchType.indirect.rawValue)]
Also, don't forget to set a correct contentSize for UIScrollView:
self.scrollView.contentSize = CGSize(width: 1920.0, height: 2000.0)

Answer 2

Finally I solved this by setting scrollView.contentSize to the appropriate size in viewDidLoad.

Answer 3

You need to add pan gesture recognizer. I learned from here: http://www.theappguruz.com/blog/gesture-recognizer-using-swift. I added more code to make it not scrolling strangely, e.g. in horizontal direction.
var currentY : CGFloat = 0 //this saves current Y position
func initializeGestureRecognizer()
{
//For PanGesture Recoginzation
let panGesture: UIPanGestureRecognizer = UIPanGestureRecognizer(target: self, action: Selector("recognizePanGesture:"))
self.scrollView.addGestureRecognizer(panGesture)
}
func recognizePanGesture(sender: UIPanGestureRecognizer)
{
let translate = sender.translationInView(self.view)
var newY = sender.view!.center.y + translate.y
if(newY >= self.view.frame.height - 20) {
newY = sender.view!.center.y //make it not scrolling downwards at the very beginning
}
else if( newY <= 0){
newY = currentY //make it scrolling not too much upwards
}
sender.view!.center = CGPoint(x:sender.view!.center.x,
y:newY)
currentY = newY
sender.setTranslation(CGPointZero, inView: self.view)
}