Button stops moving when creating new button who moves - ios

Question

I'm creating a game where a button who is being created moves from one side of the screen to the other when I click a button called start. The problem is that when I click start before the button who was moving reaches its end point, it stops instead of continuing (and the another created button start moving like expected).
Should I create a new CADisplayLink every time I click the start button? If so, how would I do that? Here's the code:
var button1 = UIButton()
var displayLink: CADisplayLink?
var startTime: CFAbsoluteTime?
let duration = 2.0
var leadingConstraint: NSLayoutConstraint!
var topConstraint: NSLayoutConstraint!
var l1 = false
#IBAction func start(sender: UIButton) {
n1()
}
func n1() {
l1 = false
startTime = CFAbsoluteTimeGetCurrent()
displayLink = CADisplayLink(target: self, selector: "handleDisplayLink:")
displayLink?.addToRunLoop(NSRunLoop.mainRunLoop(), forMode: NSRunLoopCommonModes)
}
func handleDisplayLink(displayLink: CADisplayLink) {
if l1 == false { // so it doesn't randomize leading constraint twice
button1 = createButton()
let randomNumber = Int(arc4random_uniform(180) + 30)
let elapsed = CFAbsoluteTimeGetCurrent() - startTime!
var percentComplete = CGFloat(elapsed / duration)
if percentComplete >= 1.0 {
percentComplete = 1.0
// self.button1.removeFromSuperview()
displayLink.invalidate()
button1.hidden = true
}
leadingConstraint.constant = CGFloat(randomNumber)
topConstraint.constant = 390 - 350 * percentComplete
NSLayoutConstraint.activateConstraints([
leadingConstraint,
topConstraint,
button1.widthAnchor.constraintEqualToConstant(75),
button1.heightAnchor.constraintEqualToConstant(75)
])
l1 = true
}
else{
let elapsed = CFAbsoluteTimeGetCurrent() - startTime!
var percentComplete = CGFloat(elapsed / duration)
if percentComplete >= 1.0 {
percentComplete = 1.0
displayLink.invalidate()
button1.hidden = true
}
topConstraint.constant = 390 - 350 * percentComplete
NSLayoutConstraint.activateConstraints([
leadingConstraint,
topConstraint,
button1.widthAnchor.constraintEqualToConstant(75),
button1.heightAnchor.constraintEqualToConstant(75)
])
}
}
func buttonPressed(sender: UIButton!) {
button1.hidden = true
displayLink?.invalidate()
}
func createButton() ->UIButton {
let button = UIButton()
button.setImage(UIImage(named: "BlueBall.png")!, forState: UIControlState.Normal)
button.addTarget(self, action: "buttonPressed:", forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(button)
button.translatesAutoresizingMaskIntoConstraints = false
leadingConstraint = button.leadingAnchor.constraintEqualToAnchor(view.leadingAnchor, constant: 0)
topConstraint = button.topAnchor.constraintEqualToAnchor(view.topAnchor, constant: 0)
NSLayoutConstraint.activateConstraints([
leadingConstraint,
topConstraint,
button.widthAnchor.constraintEqualToConstant(75),
button.heightAnchor.constraintEqualToConstant(75)
])
return button
}
Please help. It would be really appreciated. Thanks in advance. Anton

Answer 1

Okay Anton O; as discussed I post an answer how to detect a touch on a moving UIView. This works for both, CAAnimation and UIView.animationWith..
First I created an extension of CGRect, just for convenience:
extension CGRect {
init(position: CGPoint, size: CGSize) {
self.origin = CGPoint(x: position.x - (size.width / 2.0), y: position.y - (size.height / 2.0))
self.size = size
}
}
Then I created two methods which create and move the view. You can adapt the code then to your needs. (I hold a global variable called nextView to keep reference to the view, can also be extended to an array of course)
Create View:
private func createView(index: Int) {
nextView?.removeFromSuperview()
nextView = UIView()
nextView?.bounds = CGRect(x: 0, y: 0, width: 60, height: 60)
nextView?.backgroundColor = UIColor.redColor()
nextView?.center = CGPoint(x: 30, y: CGRectGetMidY(self.view.bounds))
if let nextView = nextView {
view.addSubview(nextView)
}
}
Move View:
private func moveView() {
guard let nextView = nextView else {
return
}
UIView.animateWithDuration(5.0) { () -> Void in
nextView.center = CGPoint(x: CGRectGetMaxX(self.view.bounds) + 30, y: CGRectGetMidY(self.view.bounds))
}
}
Detect Touch:
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
super.touchesEnded(touches, withEvent: event)
if let touch = touches.first, nextView = nextView {
let touchRect = CGRect(position: touch.locationInView(self.view), size: CGSize(width: 20, height: 20))
guard let viewPosition = nextView.layer.presentationLayer()?.position else {
return
}
let viewRect = CGRect(position: viewPosition, size: nextView.bounds.size)
if CGRectIntersectsRect(touchRect, viewRect) {
print("👍 💯")
} else {
print("👎")
}
}
}
You can extend the methods for your needs and also add some "performance" enhancing checks (like if a view is visible and move on or return right there in the touchesEnded method, etc.)