UIScrollView scroll event blocks UIView animation

Question

I have an animating set of UIImageView\'s that represent a current value and continually keeps ticking upwards...ideally never stopping, also in the view is a scrollView or to a

Answer 1

There is another way to control your animations during UIScrollview scroll with scrollView delegate methods; start your animations with Timer than stop the timer in scrollViewWillBeginDragging method and continue to your animations with displayLink etc. for example :

// Declare an displayLink
var displayLink: CADisplayLink?

// delegate your scrollview
self.scrollView.delegate = self

// start your anmiations
override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    self.startTimer()
}

// animation block
@objc private func shakeStartButton() {...}

// your animation timer
private func startTimer() {
    timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(self.shakeStartButton), userInfo: nil, repeats: true)
    timer?.fire()
}

private func startDisplayLinkIfNeeded() {
    if displayLink == nil {
        self.displayLink = CADisplayLink(target: self, selector: #selector(self.shakeStartButton))
        displayLink?.add(to: .main, forMode: .tracking)
        // Render frame only one time in second
        displayLink?.preferredFramesPerSecond = 1
    }
}

private func stopDisplayLink() {

    displayLink?.invalidate()
    displayLink = nil
}

extension YourViewController: UIScrollViewDelegate {

 func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {

    self.timer?.invalidate()
    self.startDisplayLinkIfNeeded()
 }

 func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {

    if !decelerate {
        self.stopDisplayLink()
        self.startTimer()
    }
 } 

 func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {

    self.stopDisplayLink()
    self.startTimer()
 }
}

Note: This is litte bit longer than @gehan answer but it may help with other things also?