我有一个 CAShapelayer 圆圈，我将它作为一个进度圆圈动画，CABasicAnimation 从 0 度回到 360 度，同时在状态机中使用具有重置、播放、暂停和完成状态的倒数计时器。
现在，我可以播放或暂停和恢复，直到计时器结束并且动画完成并且模型恢复到其原始值，然后选择另一个倒计时计时器值以开始动画。
但是，如果我播放然后在动画完成之前的任何时间重置，它会取消，但是当我再次播放时，动画不再起作用。我注意到由于某种原因在动画完成之前我重置后，我的 strokeEnd 不再从 0.0 开始，而是得到一个看似任意的小数点值。我认为这是我的问题的根本原因，但我不知道为什么 strokeEnd 值是这些随机数。这是 strokeEnd 值的屏幕截图 - https://imgur.com/a/YXmNkaK
这是我到目前为止所拥有的：
//draws CAShapelayer
func drawCircle() {}
//CAShapeLayer animation
func progressCircleAnimation(transitionDuration: TimeInterval, speed: Double, strokeEnd: Double) {
let fillLineAnimation = CABasicAnimation(keyPath: "strokeEnd")
fillLineAnimation.duration = transitionDuration
fillLineAnimation.fromValue = 0
fillLineAnimation.toValue = 1.0
fillLineAnimation.speed = Float(speed)
circleWithProgressBorderLayer.strokeEnd = CGFloat(strokeEnd)
circleWithProgressBorderLayer.add(fillLineAnimation, forKey: "lineFill")
}
//Mark: Pause animation
func pauseLayer(layer : CALayer) {
let pausedTime : CFTimeInterval = circleWithProgressBorderLayer.convertTime(CACurrentMediaTime(), from: nil)
circleWithProgressBorderLayer.speed = 0.0
circleWithProgressBorderLayer.timeOffset = pausedTime
}
//Mark: Resume CABasic Animation on CAShaperLayer at pause offset
func resumeLayer(layer : CALayer) {
let pausedTime = circleWithProgressBorderLayer.timeOffset
circleWithProgressBorderLayer.speed = 1.0;
circleWithProgressBorderLayer.timeOffset = 0.0;
circleWithProgressBorderLayer.beginTime = 0.0;
let timeSincePause = circleWithProgressBorderLayer.convertTime(CACurrentMediaTime(), from: nil) - pausedTime
circleWithProgressBorderLayer.beginTime = timeSincePause;
}
//Mark: Tried to removeAnimation
func resetLayer(layer : CALayer) {
layer.removeAnimation(forKey: "lineFill")
circleWithProgressBorderLayer.strokeEnd = 0.0
}
这是我在状态机中设置它的方式，以防错误与此有关：
@objc func timerIsReset() {
resetTimer()
let currentRow = timePickerView.selectedRow(inComponent: 0)
self.counter = self.Times[currentRow].amount
}
//Mark: action for RunningTimerState
@objc func timerIsStarted() {
runTimer()
}
//Mark: action for PausedTimerState
@objc func timerIsPaused() {
pauseTimer()
}
//Mark: action for TimerTimeRunOutState
func timerTimeRunOut() {
resetTimer()
}
func runTimer() {
if isPaused == true {
finishTime = Date().addingTimeInterval(-remainingTime)
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: true)
resumeLayer(layer: circleWithProgressBorderLayer)
} else if isPaused == false {
finishTime = Date().addingTimeInterval(counter)
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateTimer), userInfo: nil, repeats: true)
progressCircleAnimation(transitionDuration: counter, speed: 1.0, strokeEnd: self.completionPercentage)
}
}
//Mark: Pause Timer and pause CABasic Animation
func pauseTimer() {
timer.invalidate()
isPaused = true
remainingTime = -finishTime.timeIntervalSinceNow
completionPercentage = (counter + remainingTime) / counter
pauseLayer(layer: circleWithProgressBorderLayer)
}
func resetTimer() {
timer.invalidate()
isPaused = false
resetLayer(layer: circleWithProgressBorderLayer)
}