How to read keyPath value after animation? - ios

Question

I'm animating show and hide of my FAB button, however I want to prevent showing FAB if it is already shown. How to read current layer scale?
func hideFab(){
let materialCurve = MDCAnimationTimingFunction.deceleration
let timingFunction = CAMediaTimingFunction.mdc_function(withType: materialCurve)
let animation = CABasicAnimation(keyPath:"transform.scale.xy")
animation.timingFunction = timingFunction
animation.fromValue = 1
animation.toValue = 0
animation.duration = 0.5
animation.isRemovedOnCompletion = false
animation.fillMode = .forwards
fab.layer.playAnimation({ (layer) -> CAAnimation in
animation
}, key: animation.keyPath!)
}
func showFab(){
let materialCurve = MDCAnimationTimingFunction.deceleration
let timingFunction = CAMediaTimingFunction.mdc_function(withType: materialCurve)
let animation = CABasicAnimation(keyPath:"transform.scale.xy")
animation.timingFunction = timingFunction
animation.fromValue = 0
animation.toValue = 1
animation.duration = 0.5
animation.isRemovedOnCompletion = false
animation.fillMode = .forwards
fab.layer.playAnimation({ (layer) -> CAAnimation in
animation
}, key: animation.keyPath!)
}

Answer 1

With this let currentScale = fab.layer.presentation()?.value(forKeyPath: "transform.scale.xy") ?? 0.0 you should be able to get the presentation scale value.
But I'd try to instead check if I showed or not the FAB with a tag:
let hiddenFABTag = 99
let shownFABTag = 100
func hideFAB(){
if fab.tag == shownFABTag {
...
...
fab.tag = hiddenFABTag
}
}
func showFAB(){
if fab.tag == hiddenFABTag {
...
...
fab.tag = shownFABTag
}
}
The first time you call it, either in viewDidLoad() or somewhere, you might want to give it a default tag value, if you know if it's going to be shown or hidden the first time by saying:
override func viewDidLoad() {
super.viewDidLoad()
fab.tag = hiddenFABTag
}