Animate icons change - ios

Question

I am working on my first application, its a mathematical riddles app. The player can get a hint that will reveal one of the variables - it's basically replacing one image with another. Sometimes I am replacing more than one image so I am using a loop that replace all of them. I want the old image to fade and be replaced with the new image, the answer. Also I would like them to fade one after the other, meaning that there will be a small delay between one image replacement animation to the next.
func changeHintIcons () {
var labelsArr = [[firstEquationFirstElemnt,firstEquationSecondElemnt,firstEquationThirdElemnt],[secondEquationFirstElemnt,secondEquationSecondElemnt,secondEquationThirdElemnt],[thirdEquationFirstElemnt,thirdEquationSecondElemnt,thirdEquationthirdElemnt],[fourthEquationFirstElemnt,fourthEquationSecondElemnt,fourthEquationThirdElemnt], [fifthEquationFirstElemnt,fifthEquationSecondElemnt,fifthEquationThirdElemnt]]
let col:Int = Int(arc4random_uniform(UInt32(gameDifficulty.stages[gameLevel].umberOfVariables)))
let row:Int = Int(arc4random_uniform(UInt32(2))) * 2
let var_to_show = current_equations[col][row]
let image_name = "answer.num.\(var_to_show)"
for i in 0..<current_equations.count {
for j in 0..<current_equations[i].count {
if (current_equations[i][j] == var_to_show) {
var image_index = j
if (j > 0) {
image_index = Int(j/2) //Converting index
}
labelsArr[i][image_index]!.image = UIImage(named: image_name)! //Replacing the image
}
}
}
}
One last thing, what if I want to use in an animation instead of letting the image simply fade out? What are my options and how can I implement them?

Answer 1

Ok I found the answer. Basically swift allows you to create your animation by projecting a set of images one after the other. Follow these steps:
1. Copy animation images to assets folder
2. create an array of UIImages
3. Do the same things as I did in the animate function
Main code -
var animationArray = createImageArray(total: 14, imagePrefix: "hint.animation")
animationArray.append(UIImage(named: imageHintAnswer)!)
animate(imageView: labelsArr[i][image_index]!, images: animationArray)
Functions -
func createImageArray(total: Int, imagePrefix: String) -> [UIImage] {
var imageArray:[UIImage] = []
for imageCount in 1..<total {
let imageName = "\(imagePrefix).\(imageCount)"
let image = UIImage(named: imageName)!
imageArray.append(image)
}
return imageArray
}
func animate(imageView: UIImageView, images: [UIImage]) {
imageView.animationImages = images
imageView.animationDuration = 0.7
imageView.animationRepeatCount = 1
imageView.startAnimating()
}