关于核心动画，我是个菜鸟。我正在尝试实现UILabel从A点移动到B点的简单动画。我有以下代码是从动画代码示例中获取的，但无法正常工作。标签根本不会动。我究竟做错了什么？
let frame = self.view.frame
let blueBox = UIView(frame: frame)
blueBox.backgroundColor = UIColor(red: 46/255, green: 83/255, blue: 160/255, alpha: 1.0)
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 300, height: 400))
label.center = CGPoint(x: frame.size.width/2, y: frame.size.height/2)
label.textAlignment = .center
label.lineBreakMode = .byWordWrapping
label.numberOfLines = 0
label.layer.position = label.center
var attrsA = [NSFontAttributeName: UIFont(name: "LemonMilk", size: 92), NSForegroundColorAttributeName: UIColor.white]
var a = NSMutableAttributedString(string:"Hello\n", attributes:attrsA)
var attrsB = [NSFontAttributeName: UIFont(name: "LemonMilk", size: 38), NSForegroundColorAttributeName: UIColor.white]
var b = NSAttributedString(string:"World", attributes:attrsB)
a.append(b)
label.attributedText = a
let theAnimation = CABasicAnimation(keyPath: "position");
theAnimation.fromValue = [NSValue(cgPoint: CGPoint(x: screenWidth/2, y: screenHeight/2))]
theAnimation.toValue = [NSValue(cgPoint: CGPoint(x: 100.0, y: 100.0))]
theAnimation.duration = 3.0;
theAnimation.autoreverses = false //true - reverses into the initial value either smoothly or not
theAnimation.repeatCount = 2
blueBox.addSubview(label)
view.addSubview(blueBox)
label.layer.add(theAnimation, forKey: "animatePosition");
首先：你不能调用addSubview上label，并add(animation:)在label.layer同日而语。您只能为视图层次结构中已经存在的视图设置动画。换句话说，即使关于代码的一切都很好，您也调用add(animation:) 得太早了。尝试引入延迟。
第二：这些行是伪造的：
theAnimation.fromValue = [NSValue(cgPoint: CGPoint(x: screenWidth/2, y: screenHeight/2))]
theAnimation.toValue = [NSValue(cgPoint: CGPoint(x: 100.0, y: 100.0))]
无论是fromValue也不toValue可以是一个数组。摆脱那些括号。在Swift 3.0.1和更高版本中，您也不必强制使用NSValue。所以：
theAnimation.fromValue = CGPoint(x: screenWidth/2, y: screenHeight/2)
theAnimation.toValue = CGPoint(x: 100.0, y: 100.0)
第三：什么是fromValue平均数？如果要从标签所在的位置进行动画处理，只需省略fromValue。
因此，我将您的代码修改为以这种方式结束，并且看到了动画：
label.attributedText = a
blueBox.addSubview(label)
view.addSubview(blueBox)
delay(1) {
let theAnimation = CABasicAnimation(keyPath: "position");
theAnimation.toValue = CGPoint(x: 100.0, y: 100.0)
theAnimation.duration = 3.0;
theAnimation.autoreverses = false //true - reverses into the initial value either smoothly or not
theAnimation.repeatCount = 2
label.layer.add(theAnimation, forKey: "animatePosition");
}
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