Why the "RemoveAllAnimations()" doesn't stop my animation? - ios

Question

I have a very simple sample that allows to drag an UIView around. When touch up, I will have an inertia effect on the dragging direction for a second. While if I touch down again, I need to stop all the inertia animation and start to do another drag. Here is my code, the "clearAllAnimations" doesn't stop my animation. How could I implement that?
import UIKit
class ViewController: UIViewController {
var tile : UIView = UIView()
var labelView = UITextView()
var displayLink : CADisplayLink?
override func viewDidLoad() {
super.viewDidLoad()
tile.frame = CGRect(x: 0, y: 0, width: 256, height: 256)
tile.backgroundColor = UIColor.redColor()
view.addSubview(tile)
var panGesture = UIPanGestureRecognizer(target: self, action: Selector("panHandler:"))
view.addGestureRecognizer(panGesture)
labelView.frame = CGRect(x: 0, y: 100, width: view.frame.width, height: 44)
labelView.backgroundColor = UIColor.clearColor()
view.addSubview(labelView)
}
func panHandler (p: UIPanGestureRecognizer!) {
var translation = p.translationInView(view)
if (p.state == UIGestureRecognizerState.Began) {
self.tile.layer.removeAllAnimations()
}
else if (p.state == UIGestureRecognizerState.Changed) {
var offsetX = translation.x
var offsetY = translation.y
var newLeft = tile.frame.minX + offsetX
var newTop = tile.frame.minY + offsetY
self.tile.frame = CGRect(x: newLeft, y: newTop, width: self.tile.frame.width, height: self.tile.frame.height)
labelView.text = "x: \(newLeft); y: \(newTop)"
p.setTranslation(CGPoint.zeroPoint, inView: view)
}
else if (p.state == UIGestureRecognizerState.Ended) {
var inertia = p.velocityInView(view)
var offsetX = inertia.x * 0.2
var offsetY = inertia.y * 0.2
var newLeft = tile.frame.minX + offsetX
var newTop = tile.frame.minY + offsetY
UIView.animateWithDuration(1, delay: 0, options:UIViewAnimationOptions.CurveEaseOut, animations: {_ in
self.tile.frame = CGRect(x: newLeft, y: newTop, width: self.tile.frame.width, height: self.tile.frame.height)
}, completion: nil)
}
}
}

Answer 1

Setting UIViewAnimationOptions.AllowUserInteraction does the trick. The new code to start animation is this:
UIView.animateWithDuration(animationDuration, delay: 0, options:UIViewAnimationOptions.CurveEaseOut | UIViewAnimationOptions.AllowUserInteraction | UIViewAnimationOptions.BeginFromCurrentState, animations: {_ in
self.tile.frame = CGRect(x: newLeft, y: newTop, width: self.tile.frame.width, height: self.tile.frame.height)
}, completion: nil)