Animate UIView background color swift

问题:

I'd like to animate background of UIView with random colours. here's what i've done so far:

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)
    }

}

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.

回答1:

Just put the animation in getRandomColor.

func getRandomColor() {
    let red   = CGFloat((arc4random() % 256)) / 255.0
    let green = CGFloat((arc4random() % 256)) / 255.0
    let blue  = CGFloat((arc4random() % 256)) / 255.0
    let alpha = CGFloat(1.0)

    UIView.animate(withDuration: 1.0, delay: 0.0, options:[.repeat, .autoreverse], animations: {
        self.view.backgroundColor = UIColor(red: red, green: green, blue: blue, alpha: alpha)
    }, completion:nil)
}