UILabel text fade out one by one - ios

Question

I want to figure out how to fade out text one by on in UILabel.
For example:
label.text = "abcdefg", I want to let the text fade out one by one -> 'a','b','c','d','e','f','g' fade out respectively.
How could I do this?
Thanks for all your answers, I want to clarify that I want an animation to fade out, something like UIViewAnimationOptions.CurveEaseInOut.
Thanks!

Answer 1

Use 2 labels and fade them in and out repeatedly, removing characters from each between each fade.
first shown with abcdefg second hidden with abcdef
fade first out and second in
first hidden with abcde second shown with abcdef
fade first in and second out
etc
Or, use the view capture SDK to create images of your label with different text content and then animate through the images with some transition.

Answer 2

You can do it with using NSTimer and remove the last letter from string of its intervention. For example you can do something like this:
Simple class for fade text animation
class TextFadeAnimation {
var text: String
var timer: NSTimer?
var block: ((text: String) -> Void)?
init(text: String) {
self.text = text
}
func startAnimation(resultTextBlock block: (text: String) -> Void) {
self.block = block
timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: Selector("fadeOut"), userInfo: nil, repeats: true)
}
func stopAnimation() {
if timer != nil {
timer!.invalidate()
}
}
#objc private func fadeOut() {
if count(text) > 1 {
text = text.substringToIndex(text.endIndex.predecessor())
block!(text: text)
} else {
timer!.invalidate()
block!(text: "")
}
}
}
Use example in ViewController
class ViewController: UIViewController {
#IBOutlet weak var label: UILabel!
var textFadeAnimation: TextFadeAnimation?
override func viewDidLoad() {
super.viewDidLoad()
textFadeAnimation = TextFadeAnimation(text: "abcdefg")
textFadeAnimation!.startAnimation(resultTextBlock: { (text: String) -> Void in
self.label.text = text
})
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}