How to Cancel Scrolling in UIScrollView

Question

I use UIScrollView to make large-sized (larger than 320px) UI on iPhone.

I made an instance of UIScrollView and added some subviews on it. The problem is that I want

Answer 1

My problem was having a view that a user could draw in but the scroll view was hijacking the touch and scrolling instead of drawing. This is my working solution:

In my drawing view I have:

override func touchesBegan(_ touches: Set, with event: UIEvent?) {

    // Disable scroll on touch begin
    setContainerScrollingEnabled(false)
    super.touchesBegan(touches, with: event)
}

override func touchesEnded(_ touches: Set, with event: UIEvent?) {

    // Reenable scroll on touch end
    setContainerScrollingEnabled(true)
    super.touchesEnded(touches, with: event)
}

private func setContainerScrollingEnabled(_ enabled: Bool) {

    // loop up superviews to find the scrollview
    func scrollingSuperview(of view: UIView) -> UIScrollView? {
        guard let superview = view.superview else { return nil }
        if let scrolling = view.superview as? UIScrollView { return scrolling }
        return scrollingSuperview(of: superview)
    }

    // and switch on/off scrolling
    let scrollView = scrollingSuperview(of: self)
    scrollView?.isScrollEnabled = enabled
}

and in the view controller containing the scroll view I have:

// Not sure what exactly this does, but I think it allows the drawing view to have precedence. This was the missing piece of the puzzle.
scrollView.delaysContentTouches = false