CODEWITHSUNDEEP
iosxcodeswiftcalayercaanimation
OriginalAlchemist
OriginalAlchemist

Reputation: 411

Swift : Pause CABasicAnimation for CALayer

The code you see below creates a CALayer(rectangle shape) and animates it from the left to the right(you can copy and paste code directly in new project):

     //Global Variables
var layer = CALayer()
var holdGesture = UILongPressGestureRecognizer()
let animation = CABasicAnimation(keyPath: "bounds.size.width")


func setUpView(){

    self.view.addGestureRecognizer(holdGesture)
    holdGesture.addTarget(self, action:"handleLongPress:")

}


func handleLongPress(sender : UILongPressGestureRecognizer){

    //NEED IT HERE
    //var layer = CALayer()

    layer.frame = CGRect(x: 0, y: 0, width: 0, height: 10)
    layer.backgroundColor = UIColor.redColor().CGColor

    animation.fromValue = 0
    animation.toValue = self.view.bounds.width * 2
    animation.duration = 5
    self.view.layer.addSublayer(layer)

    if(sender.state == .Began){
        print("Long Press Began")
        layer.addAnimation(animation, forKey: "bounds.size.width")
    }


    else{
        print("Long press ended")
        pauseLayer(layer)
    }

}

func pauseLayer(layer : CALayer){
    let pausedTime : CFTimeInterval = layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
    layer.speed = 0.0
    layer.timeOffset = pausedTime

}



override func didReceiveMemoryWarning(){
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    setUpView()

}

The issue I'm having is the variable "layer" can only be paused(when passed through the "pauseLayer" function) if it is a global variable! I do not know why! I want to declare the variable within the "handleLongPress" function.The reason for this is because i need to declare a new variable with the same name every time the longPressGestureRecognizer is recognized. Ive tried pass by reference with "inout" but it didn't seem to work. Can someone help? Please.

Upvotes: 2

Views: 4633

Answers (3)

argus7
argus7

Reputation: 95

Here is the function for pause you animation and again restart at the same time

  func pauseAnimation(){
  var pausedTime = layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
  layer.speed = 0.0
  layer.timeOffset = pausedTime
}

func resumeAnimation(){
  var pausedTime = layer.timeOffset
  layer.speed = 1.0
  layer.timeOffset = 0.0
  layer.beginTime = 0.0
  let timeSincePause = layer.convertTime(CACurrentMediaTime(), fromLayer: nil) - pausedTime
  layer.beginTime = timeSincePause
}

Upvotes: 1

Nguyễn Quang Tuấn
Nguyễn Quang Tuấn

Reputation: 1082

Pause layer 

func pauseLayer(layer : CALayer){
    let pausedTime : CFTimeInterval = layer.convertTime(CACurrentMediaTime(), from: nil)
    layer.speed = 0.0
    layer.timeOffset = pausedTime

}

And i bonus to you resume function :D 

func resumeAnimation(layer : CALayer){
    let pausedTime = layer.timeOffset
    layer.speed = 1.0
    layer.timeOffset = 0.0
    layer.beginTime = 0.0
    let timeSincePause = layer.convertTime(CACurrentMediaTime(), from: nil) - pausedTime
    layer.beginTime = timeSincePause
}

Upvotes: 8

Aruna Mudnoor
Aruna Mudnoor

Reputation: 4825

Use this Modified code:

//Global Variables
var layer: CALayer?
var holdGesture = UILongPressGestureRecognizer()
let animation = CABasicAnimation(keyPath: "bounds.size.width")


func setUpView(){

    self.view.addGestureRecognizer(holdGesture)
    holdGesture.addTarget(self, action:"handleLongPress:")

}


func handleLongPress(sender : UILongPressGestureRecognizer){

    if(sender.state == .Began) {

        let newLayer = CALayer()
        newLayer.frame = CGRect(x: 0, y: 0, width: 0, height: 10)
        newLayer.backgroundColor = UIColor.redColor().CGColor

        animation.fromValue = 0
        animation.toValue = self.view.bounds.width * 2
        animation.duration = 5
        self.view.layer.addSublayer(newLayer)

        print("Long Press Began")
        newLayer.addAnimation(animation, forKey: "bounds.size.width")

        layer = newLayer
    }
    else {
        print("Long press ended")

        if let layer = layer {
            pauseLayer(layer)
            layer.removeFromSuperlayer()
        }
    }

}

func pauseLayer(layer : CALayer){
    let pausedTime : CFTimeInterval = layer.convertTime(CACurrentMediaTime(), fromLayer: nil)
    layer.speed = 0.0
    layer.timeOffset = pausedTime

}

Upvotes: 5

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