Play animation wait 2 seconds and repeat - ios

Question

I'm using UIView.animate to animate a simple UIView.
Starting conditions: width = height = 30, color = blue (I set this in the Storyboard)
I want to increase the size to w=50, h=50 and make it white, while it has an appropriate cornerRadius. Then I reset the view and do the same animation again.
Here is my code:
class ViewController: UIViewController {
#IBOutlet weak var swipeRightView: UIView!
#IBOutlet weak var doubleTab: UIView!
override func viewDidLoad() {
super.viewDidLoad()
for _ in 0...2 {
startAnimation()
sleep(5)
self.doubleTab.layer.removeAllAnimations()
startAnimation()
}
}
func startAnimation() {
self.doubleTab.layer.cornerRadius = 15
UIView.animate(withDuration: 1.5, delay: 0, options: [.curveLinear], animations: {
self.doubleTab.backgroundColor = UIColor.white
self.doubleTab.frame.size.width += 20
self.doubleTab.frame.size.height += 20
self.doubleTab.layer.cornerRadius = self.doubleTab.frame.size.width / 2
}) { (_) in
self.doubleTab.backgroundColor = UIColor(displayP3Red: 0.34, green: 0.61, blue: 0.88, alpha: 1)
self.doubleTab.frame.size = CGSize(width: 30, height: 30)
self.doubleTab.layer.cornerRadius = self.doubleTab.frame.size.width / 2
UIView.animate(withDuration: 1.5, delay: 0, options: [.curveLinear], animations: {
self.doubleTab.backgroundColor = UIColor.white
self.doubleTab.frame.size.width += 20
self.doubleTab.frame.size.height += 20
self.doubleTab.layer.cornerRadius = self.doubleTab.frame.size.width / 2
}, completion: nil)
}
}
}
This works fine but i want to repeat the whole animation. When the whole animation is finished I want to wait 2 seconds and then repeat it, then wait 2 seconds and repeat and so on. As you can see in viewDidLoad I tried to repeat the animation with a for-loop but this has no affect or a wrong behavior. A repeat - while has also no effect. So, how can i repeat this animation?
Any help is highly appreciated.

Answer 1

In this case, you could call the startAnimation function recursively, which means call it again after it's completed, which will call itself again after it completed and so on.
So you could basically add , completion: { _ in self.startAnimation() } in the last block where you've currently set completion: nil.
If you wanted to add a delay, you could add the delay in the function as parameter and make it 0 by default for the first animation cycle.
The full code would then be:
func startAnimation(delay: TimeInterval = 0) {
self.doubleTab.layer.cornerRadius = 15
UIView.animate(withDuration: 1.5, delay: delay, options: [.curveLinear], animations: {
self.doubleTab.backgroundColor = UIColor.white
self.doubleTab.frame.size.width += 20
self.doubleTab.frame.size.height += 20
self.doubleTab.layer.cornerRadius = self.doubleTab.frame.size.width / 2
}) { (_) in
self.doubleTab.backgroundColor = UIColor(displayP3Red: 0.34, green: 0.61, blue: 0.88, alpha: 1)
self.doubleTab.frame.size = CGSize(width: 30, height: 30)
self.doubleTab.layer.cornerRadius = self.doubleTab.frame.size.width / 2
UIView.animate(withDuration: 1.5, delay: 0, options: [.curveLinear], animations: {
self.doubleTab.backgroundColor = UIColor.white
self.doubleTab.frame.size.width += 20
self.doubleTab.frame.size.height += 20
self.doubleTab.layer.cornerRadius = self.doubleTab.frame.size.width / 2
}, completion: { _ in
self.startAnimation(delay: 2)
})
}
}