How do I wait for one animation to finish before the next one starts in Swift?

Question

How do I wait for one animation to finish before the next one starts in Swift? I have been messing around with if animation.animationDidStop... {}, but it won't work.

Here's some of my code so far:

class ViewController: UIViewController {
@IBOutlet weak var purpleRing: UIImageView!
@IBOutlet weak var beforeCountdownAnimation: UIImageView!

var imageArray = [UIImage]()
var imageArray2 = [UIImage]()

override func viewDidLoad() {
    super.viewDidLoad()

    for e in -17...0 {
    let imageName2 = "\(e)"
        imageArray2.append(UIImage(named: imageName2)!)
    }

    for t in 1...97 {
        let imageName = "\(t)"
        imageArray.append(UIImage(named: imageName)!)
    }
}

func startAnimation() -> Void {
    purpleRing.animationImages = imageArray
    purpleRing.animationDuration = 5.0
    purpleRing.startAnimating()
}

func startAnimation2() -> Void {
    beforeCountdownAnimation.animationImages = imageArray2
    beforeCountdownAnimation.animationDuration = 1.0
    beforeCountdownAnimation.startAnimating()
}

@IBAction func startAnimations(sender: AnyObject) {
    startAnimation()
    startAnimation2()
}

Answer 1

Erm, probably answered before, but you can use Grand Central Dispatch dispatc_aysnc.

The idea is that, you know the animation duration, so you use that to tell the GDC when to execute the next code. So something like:

// call animation 1, which you specified to have 5 second duration
CGFloat animation1Duration = 5.0;
CGFloat animation2Duration = 7.0;

playAnimation1WithDuration(animation1Duration);

// calling second animation block of code after 5.0 using GDC
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(animation1Duration * Double(NSEC_PER_SEC))), dispatch_get_main_queue(), { () -> Void in

    print("5.0 has passed");

    // call second animation block here
    playAnimation2WithDuration(animation2Duration);

});