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Animation - object stays fixed on screen during animation.

Forums > Swift

Hello everybody,

I am trying to do an animation with ballons and I want them to float from the bottom to the top of the screen. However in the middle of the animation one of the ballons gets fixated in the top left corner while other ballons are still floating.

I recorded a video for you to see...

Here is my code....

func presentVictoryView() {

        blackView.isHidden = false

        for _ in 0 ... 20 {

            let objectView = UIView()
            objectView.translatesAutoresizingMaskIntoConstraints = false
            objectView.frame = CGRect(x: 0, y: 0, width: 20, height: 100)
            //objectView.backgroundColor = .clear
            //objectView.alpha = CGFloat(0.9)
            objectView.isHidden = false

            let ballon = UILabel()
            ballon.translatesAutoresizingMaskIntoConstraints = false
            ballon.frame = CGRect(x: 0, y: 0, width: 20, height: 100)
            //ballon.backgroundColor = .clear
            //ballon.alpha = CGFloat(0.9)
            ballon.text = "🎈"
            ballon.font = UIFont.systemFont(ofSize: 60)

                ballon.centerXAnchor.constraint(equalTo: objectView.centerXAnchor),
                ballon.centerYAnchor.constraint(equalTo: objectView.centerYAnchor)


            let randomXOffset = Int.random(in: -120 ..< 200)

            let path = UIBezierPath()
            path.move(to: CGPoint(x: 270 + randomXOffset, y: 1000))
            path.addCurve(to: CGPoint(x: 100 + randomXOffset, y: -300), controlPoint1: CGPoint(x: 300 - randomXOffset, y: 600), controlPoint2: CGPoint(x: 70 + randomXOffset, y: 300))

            let animation = CAKeyframeAnimation(keyPath: "position")
            animation.path = path.cgPath
            animation.repeatCount = 1

            let random = Double.random(in: 3.0 ..< 7.0)
            animation.duration = random
            //animation.timeOffset = Double(arc4random_uniform(50))

            objectView.layer.add(animation, forKey: "animate position along path")



Thank you.


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