如何将 NSLayoutConstraint 转换为 CABasicAnimation 中可用的值？

Question

我想通过 CABasicAnimation 将 blueView 移动到视图中心。这是我的代码：

import Cocoa

class ViewController: NSViewController {
    
    private let blueView: NSView = NSView()
    
    private lazy var blueViewCenterXAnchor: NSLayoutConstraint? = nil
    private lazy var blueViewCenterYAnchor: NSLayoutConstraint? = nil
    private lazy var blueViewWidthAnchor: NSLayoutConstraint? = nil
    private lazy var blueViewHeightAnchor: NSLayoutConstraint? = nil
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.wantsLayer = true
        
        blueView.wantsLayer = true
        blueView.layer?.backgroundColor = NSColor.blue.cgColor
        
        
        self.view.addSubview(blueView)
        
        blueView.translatesAutoresizingMaskIntoConstraints = false
        
        blueViewCenterXAnchor = blueView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor, constant: -300.0)
        blueViewCenterYAnchor = blueView.centerYAnchor.constraint(equalTo: self.view.centerYAnchor)
        blueViewWidthAnchor = blueView.widthAnchor.constraint(equalToConstant: 200.0)
        blueViewHeightAnchor = blueView.heightAnchor.constraint(equalToConstant: 200.0)

        blueViewCenterXAnchor?.isActive = true
        blueViewCenterYAnchor?.isActive = true
        blueViewWidthAnchor?.isActive = true
        blueViewHeightAnchor?.isActive = true
        
        DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + DispatchTimeInterval.seconds(1)) {

             self.updateConstantViaCABasicAnimation()
            
        }
        
    }

    func updateConstantViaCABasicAnimation() {
        let animation = CABasicAnimation()
        animation.keyPath = "position.x"
        animation.fromValue = blueViewCenterXAnchor!.constant // need to convert it to usable value
        animation.toValue = blueViewCenterXAnchor!.constant + 300.0 // need to convert it to usable value
        animation.duration = 1.0
        blueView.layer?.add(animation, forKey: "basic")
        //blueView.layer?.position = CGPoint(x: self.view.centerXAnchor.x, y: self.view.centerXAnchor.y)  // need to convert it to usable value
    }
    
}

在这段代码中，如您所见，我正在尝试访问 blueViewCenterXAnchor 携带的数据或值，以避免建立所需值的数学计算。所以问题的目标不是用数学方法解决问题，而是访问视图的 NSLayoutConstraint。在这行代码中，我将常量从

self.view.centerXAnchor

设置为 -300.0，以便稍后使用动画移动到 self.view.centerXAnchor。这意味着完成动画后，蓝色视图应该位于

self.view

的中心。

来自：

blueView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor, constant: -300.0)

至：

blueView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor, constant: 0.0)

所以我遇到了访问动画所需值以避免数学计算的问题。动画有效但方式错误。那么我应该怎么做呢？

这个问题的主要目标基本上是用

CABasicAnimation

更新NSLayoutConstraint，如果我的代码示例不适合解决这个目标的问题，你可以用你自己的示例代码来回答，用CABasicAnimation更新NSLayoutConstraint。