ios - CAKeyframeAnimation 在 Nib 中不起作用

Question

我有一个 nib 文件，它必须为 View 设置动画以在圆形路径中移动。但是当我运行我的代码时，我看到 View 没有动画并且在我 View 的顶角

这是我的代码

override func awakeFromNib() {

        let circlePath = UIBezierPath(arcCenter: CGPointMake(CGRectGetMidX(loadingview.bounds), CGRectGetMidY(loadingview.bounds)), radius: 30, startAngle: 0, endAngle:CGFloat(M_PI)*2, clockwise: true)

        let animation = CAKeyframeAnimation(keyPath: "position")
        animation.beginTime = 0.0
        animation.duration = 1
        animation.repeatCount = Float.infinity
        animation.path = circlePath.CGPath

        let squareView = UIView()
        squareView.frame = CGRectMake(0, 0, 10, 10);
        squareView.backgroundColor = UIColor.grayColor()

        self.addSubview(squareView)
        // You can also pass any unique string value for key


        // circleLayer is only used to locate the circle animation path
        let circleLayer = CAShapeLayer()
        circleLayer.path = circlePath.CGPath
        circleLayer.strokeColor = UIColor.blackColor().CGColor
        circleLayer.fillColor = UIColor.clearColor().CGColor
        loadingview.layer.addSublayer(circleLayer)

        squareView.layer.addAnimation(animation, forKey: "position")

        self.layer.shadowColor = UIColor.blackColor().CGColor
        self.layer.shadowOpacity = 1
        self.layer.shadowOffset = CGSize.zero
        self.layer.shadowRadius = 1
        self.layer.cornerRadius = 10.0
    }

Answer 1

您不能在 awakeFromNib 中开始动画。现在还为时过早。你只能动画一个实际在你界面的view/layer hierarchy中的layer，而刚刚从nib出来的view的layer，比如loadingview，还没有被放到完整的界面中还没有。

此外，这看起来是 CABasicAnimation，而不是 CAKeyframeAnimation。你需要解决这个问题。