swift - CAShapeLayer 动画不会触发 animationDidStop

Question

使用 Swift 3.0 运行 tvOS

基本应用程序，这是 View Controller 中的代码...我想在 CAShapeLayer 淡出后删除它。动画完美运行，但是完成方法 animationDidStop 永远不会被调用？

想使用override func animationDidStop 方法，但无法编译。给我错误“方法没有覆盖其父类(super class)中的任何方法”，这肯定是错误的，animationDidStop 是 CAAnimation 类的成员。

这段代码有什么问题？我可以用计时器或我猜的其他东西来解决这个问题，但这是一个软糖。

import UIKit
import QuartzCore


class ViewController: UIViewController, CALayerDelegate, CAAnimationDelegate {

var shapeLayer = CAShapeLayer()


override func viewDidLoad() {
    super.viewDidLoad()
    highlight(XCord: 100, YCord: 100)
    clearhighlight()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func highlight(XCord: CGFloat, YCord: CGFloat) {
    DispatchQueue.main.async {
        let circlePath = UIBezierPath(arcCenter: CGPoint(x: XCord,y: YCord), radius: CGFloat(20), startAngle: CGFloat(0), endAngle:CGFloat(M_PI * 2), clockwise: true)

        self.shapeLayer.path = circlePath.cgPath

        //change the fill color
        //shapeLayer.fillColor = UIColor.clear.cgColor
        self.shapeLayer.fillColor = UIColor.red.cgColor
        self.shapeLayer.opacity = 0.5
        self.shapeLayer.fillRule = kCAFillRuleEvenOdd

        //you can change the stroke color
        self.shapeLayer.strokeColor =  UIColor.red.cgColor
        //you can change the line width
        self.shapeLayer.lineWidth = 3.0

        DispatchQueue.main.async {
            self.view.layer.addSublayer(self.shapeLayer)
        }
    }
}

func clearhighlight() {
    DispatchQueue.main.async {
        let fadeInAndOut = CABasicAnimation(keyPath: "opacity")
        fadeInAndOut.duration = 10.0;
        //fadeInAndOut.autoreverses = true;
        fadeInAndOut.repeatCount = 1
        fadeInAndOut.fromValue = 1.0
        fadeInAndOut.toValue = 0.0
        fadeInAndOut.isRemovedOnCompletion = true
        fadeInAndOut.fillMode = kCAFillModeForwards;
        //self.view.layer.delegate = self
        self.shapeLayer.delegate = self
        self.shapeLayer.add(fadeInAndOut, forKey: "fadeOut")
        self.shapeLayer.setNeedsDisplay()
    }
}

func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
    print("animationDidStop")
    DispatchQueue.main.async {
        self.shapeLayer.removeFromSuperlayer()
    }
}



}

Answer 1

您正在设置形状层的委托(delegate):

self.shapeLayer.delegate = self

但是如果你想调用animationDidStop，你必须设置动画的delegate，而不是层的:

fadeInAndOut.delegate = self

---

你说:

Want to use override func animationDidStop method, but it won't compile. Gives me the error "method does not override any method from its superclass" which is wrong surely, animationDidStop is a member of CAAnimation class.

您正在您的 View Controller 中实现它并且 UIViewController 不提供 animationDidStop 的基类实现，因此没有什么可以覆盖。

animationDidStop 是由 CAAnimationDelegate 协议(protocol)定义的方法，因此 (a) View Controller 应声明其符合该协议(protocol)； (b) 不要使用 override 关键字。