当模态地显示另一个VC时，CABasicAnimation会被完成
我用下面的方法暂停/恢复animation
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 } 只要当前呈现ViewController，它就像魅力一样。
当我以模态方式呈现另一个视图控制器，然后将其解除时，无论本次/解散操作过程耗费了多less时间，animation都会完成。
你有什么build议，为什么会发生这种情况？ 如何解决它？ 我想补充说，所有其他的视图保持其状态，只有animation完成。
编辑：
我刚才发现，在这种情况下，暂停/恢复正在进行的animation也会完成。
这是我的代码，显示animation实现
import Foundation import UIKit class CircleView: UIView { var circleLayer: CAShapeLayer! @IBOutlet var view: UIView! @IBOutlet weak var progressLabel: UILabel! required init?(coder aDecoder: NSCoder) { super.init(coder: aDecoder) Bundle.main.loadNibNamed("CircleView", owner: self, options: nil) self.addSubview(view) view.frame = self.bounds } override func awakeFromNib() { super.awakeFromNib() setupAppearance() } func setupAppearance() { progressLabel.textColor = UIColor.textColor progressLabel.font = UIFont.textTimerClock } func setup(progress:Double, clockwise:Bool) { self.backgroundColor = UIColor.clear var strokeColor = UIColor.positiveProgressColor if !clockwise { strokeColor = UIColor.positiveProgressColor } // Use UIBezierPath as an easy way to create the CGPath for the layer. // The path should be the entire circle. let circlePath = UIBezierPath(arcCenter: CGPoint(x: frame.size.width / 2.0, y: frame.size.height / 2.0), radius: (frame.size.width - 10)/2, startAngle: 0.0, endAngle: CGFloat(.pi * 2 * progress), clockwise: clockwise) // Setup the CAShapeLayer with the path, colors, and line width circleLayer = CAShapeLayer() circleLayer.path = circlePath.cgPath circleLayer.fillColor = UIColor.clear.cgColor circleLayer.strokeColor = strokeColor.cgColor circleLayer.lineWidth = 8.0; // Don't draw the circle initially circleLayer.strokeEnd = 0.0 // Add the circleLayer to the view's layer's sublayers layer.addSublayer(circleLayer) //add grey path let greyCircleLayer = CAShapeLayer() let greyCirclePath = UIBezierPath(arcCenter: CGPoint(x: frame.size.width / 2.0, y: frame.size.height / 2.0), radius: (frame.size.width - 10)/2, startAngle: 0.0, endAngle: CGFloat(.pi * 2.0), clockwise: true) greyCircleLayer.path = greyCirclePath.cgPath greyCircleLayer.fillColor = UIColor.clear.cgColor greyCircleLayer.strokeColor = UIColor.appLightGrey.cgColor greyCircleLayer.lineWidth = 1.0; // Don't draw the circle initially circleLayer.strokeEnd = 0.0 // Add the circleLayer to the view's layer's sublayers layer.insertSublayer(greyCircleLayer, below: circleLayer) if progressLabel != nil { progressLabel.text = "10"} } func pauseAnimation(){ let pausedTime = circleLayer.convertTime(CACurrentMediaTime(), from: nil) circleLayer.speed = 0.0 circleLayer.timeOffset = pausedTime } func resumeAnimation(){ let pausedTime = circleLayer.timeOffset circleLayer.speed = 1.0 circleLayer.timeOffset = 0.0 circleLayer.beginTime = 0.0 let timeSincePause = layer.convertTime(CACurrentMediaTime(), from: nil) - pausedTime circleLayer.beginTime = timeSincePause } func animateCircle(duration: TimeInterval, color: UIColor) { // We want to animate the strokeEnd property of the circleLayer circleLayer.strokeColor = color.cgColor let animation = CABasicAnimation(keyPath: "strokeEnd") // Set the animation duration appropriately animation.duration = duration // Animate from 0 (no circle) to 1 (full circle) animation.fromValue = 0 animation.toValue = 1 // Do a linear animation (ie the speed of the animation stays the same) animation.timingFunction = CAMediaTimingFunction(name: kCAAnimationLinear) // Set the circleLayer's strokeEnd property to 1.0 now so that it's the // right value when the animation ends. circleLayer.strokeEnd = 1.0 // Do the actual animation circleLayer.add(animation, forKey: "animateCircle") } }
另外值得一提的是：init（），awakeFromNib（）不会被再次调用，所以情况并非如此。
另一个：推动VC而不是模态呈现相同的情况。
通常，当您显示另一个视图控制器时，当前视图控制器的视图将从窗口中删除。 这也将从其图层中删除所有悬而未决的animation，并且任何现有的animation完成处理程序都会调用false ，因为animation未完成（另请参阅https://stackoverflow.com/a/21200504/2352344 ）。
要在返回到视图控制器后继续animation，您应该在viewWillAppear重buildanimation对象。