ios - animationDidStop 没有被调用？

Question

我不确定出了什么问题，我确保将委托(delegate)设置为 self 但它仍然没有被调用。这是代码:

  override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    //animate form
    let flyRight = CABasicAnimation(keyPath: "position.x")
    flyRight.fromValue = -view.bounds.size.width/2
    flyRight.toValue = view.bounds.size.width/2
    flyRight.duration = 0.5
    heading.layer.add(flyRight, forKey: nil)

    flyRight.isRemovedOnCompletion = false
    flyRight.fillMode = kCAFillModeForwards

    flyRight.delegate = self as? CAAnimationDelegate
    flyRight.setValue("form", forKey: "name")
    flyRight.setValue(username.layer, forKey: "layer")
}

这是animationDidStop:

  func animationDidStop(_ anim: CAAnimation!, finished flag: Bool) {
    let nameValue = anim.value(forKey: "name") as? String
    if let name = nameValue {
      if name == "form" {
        let layer: CALayer = anim.value(forKey: "layer")! as! CALayer
        layer.position.x = view.bounds.width/2
        anim.setValue(nil, forKey: "layer")
      }
    }
  }

Answer 1

在你的类声明中你没有遵守协议(protocol)

class MyViewController: UIViewController, CAAnimationDelegate {
// ... 
}