title: Animate UIView background color swift
body: <p>I'd like to animate background of UIView with random colours. 
  here's what i've done so far:</p>
  
  <pre><code>import UIKit
  
  class ViewController: UIViewController {
  
      var timer = NSTimer()
      var colours = UIColor()
  
      override func viewDidLoad() {
          super.viewDidLoad()
          getRandomColor()
          timerF()
  
          UIView.animateWithDuration(2, delay: 0.0, options:[UIViewAnimationOptions.Repeat, UIViewAnimationOptions.Autoreverse], animations: {
              self.view.backgroundColor = self.colours
  
              }, completion:nil)
      }
  
      func timerF(){
           timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("getRandomColor"), userInfo: nil, repeats: true)
      }
  
      func getRandomColor(){
          let red   = Float((arc4random() % 256)) / 255.0
          let green = Float((arc4random() % 256)) / 255.0
          let blue  = Float((arc4random() % 256)) / 255.0
          let alpha = Float(1.0)
          colours = UIColor(colorLiteralRed: red, green: green, blue: blue, alpha: alpha)
      }
  
  }
  </code></pre>
  
  <p>But it just generates a random colour at the start and use this single colour in my animation. I'd like to find a way to animate colours, so UIVIew background would look like a random rainbow.</p>