How to detect a touch on a moving (animation) UIImageView? - ios

Question

I'm trying to add UITapGestureRecognizer on a UIImageView while its moving but the clic is only working when the animation is static.
I've looked everywhere on the internet but couldn't find a solution.
Is there a solution to this problem?
Here's the code I'm working with: I'm creating 10 "bubbles" containing a round image. I animate them so they're moving up and fading. I'd like to be able to click on them and get their tag (int form 1 to 10).
#IBAction func startBubble(sender: AnyObject) {
//var bubble = UIView()
let screenSize = UIScreen.mainScreen().bounds
let screenWidth = screenSize.width
let screenHeight = screenSize.height
// Animation parameters
let duration : NSTimeInterval = 9.0
var delay : NSTimeInterval = 1.0
var minimumDelay : NSTimeInterval = 3.0
let factor : CGFloat = 1.75
let opacity : CGFloat = 0.3
let options: UIViewAnimationOptions = [.CurveEaseIn, .AllowUserInteraction]
for bubbleNumber in 1...10 {
// Bubble size
let bubbleWidth : CGFloat = CGFloat(arc4random_uniform(40) + 130)
let bubbleHeight = bubbleWidth
// Bubble start position
let startPosition : CGFloat = CGFloat(arc4random_uniform(UInt32(screenWidth - bubbleWidth)))
// Bubble delay
if bubbleNumber > 1 {
minimumDelay = minimumDelay + NSTimeInterval(3.0)
delay = minimumDelay + (NSTimeInterval(arc4random_uniform(1000)) / 1000)
}
let bubble = UIImageView(frame: CGRectMake(startPosition, screenHeight, bubbleWidth, bubbleHeight))
// Bubble definition
bubble.image = UIImage(named: "bubble.png")
bubble.tag = bubbleNumber
bubble.userInteractionEnabled = true
bubble.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "openBubble:"))
self.view.addSubview(bubble)
UIView.animateWithDuration(duration, delay: delay, options: options, animations: {
bubble.frame = CGRectMake(startPosition, 1, factor*bubbleWidth, factor*bubbleHeight)
bubble.alpha = opacity
}, completion: { animationFinished in
bubble.alpha = 0.1
bubble.removeFromSuperview()
})
}
}
func openBubble(sender:UITapGestureRecognizer){
let tappedBubble = sender.view!
print(tappedBubble.tag)
}