UIImageView animation in Swift with time delay - ios

Question

I'm stuck with this issue where I want a UIImage to glow within two seconds and then to go back to it's normal state.
Given this issue here's what I have at the moment:
I have the image views referenced, from 0 to 9.
#IBOutlet weak var imageOne: UIImageView!
#IBOutlet weak var imageTwo: UIImageView!
etc.
Then I added them to SubViews in the viewDiDLoad() function:
override func viewDidLoad() {
super.viewDidLoad()
self.view.addSubview(imageOne)
self.view.addSubview(imageTwo)
etc.
}
Here is my implementation of the colorisation function:
func colorize(imageView: UIImageView, color: CGColorRef) {
imageView.layer.shadowColor = color
imageView.layer.shadowRadius = 7.0
imageView.layer.shadowOpacity = 0.9
imageView.layer.shadowOffset = CGSizeZero
imageView.layer.masksToBounds = false
}
Now, I'm trying to animate two image views which are called through this. a and b are just randoms acquired from the previous view. In this example, they will be 1 and 3.:
UIView.animateWithDuration(2.0, delay: 0, options: nil, animations: { () -> Void in
self.colorize(labelArray[a.toInt()!], color:self.green)
}, completion: nil)
UIView.animateWithDuration(2.0, delay: 2.0, options: nil, animations: { () -> Void in
self.colorize(labelArray[b.toInt()!], color:self.cyan)
}, completion: nil)
Now, this is what the view looks like beforehand -
And this is what it's like after, but both animations occur at the same time. There is no transition. It just automatically applies the glow -
Thanks for your help!

Answer 1

Since you're trying to animation your UIImageView layers, try using Core Animation instead of UIView animation blocks since Core Animation must be used to animate the shadow layer of a view. If you simply want to fade the shadow in, try this to animate the shadow opacity:
override func performGlowAnimations {
self.colorize(labelArray[a.toInt()!], color:self.green)
// Delay the second call by 2 seconds
let delay = 2.0 * Double(NSEC_PER_SEC)
var time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
dispatch_after(time, dispatch_get_main_queue(), {
self.colorize(labelArray[b.toInt()!], color:self.cyan)
})
}
func colorize(imageView: UIImageView, color: CGColorRef) {
// Set the image's shadowColor, radius, offset, and
// set masks to bounds to false
imageView.layer.shadowColor = color
imageView.layer.shadowRadius = 7.0
imageView.layer.shadowOffset = CGSizeZero
imageView.layer.masksToBounds = false
// Animate the shadow opacity to "fade it in"
let shadowAnim = CABasicAnimation()
shadowAnim.keyPath = "shadowOpacity"
shadowAnim.fromValue = NSNumber(float: 0.0)
shadowAnim.toValue = NSNumber(float: 0.9)
shadowAnim.duration = 2.0
imageView.layer.addAnimation(shadowAnim, forKey: "shadowOpacity")
imageView.layer.shadowOpacity = 0.9
}