ios - CABasicAnimation:从左到右

Question

通过下面的代码，我可以从左到右为 CALayer 制作动画

let imageLayer = CALayer()
imageLayer.frame = CGRect(x: 0, y: 500, width: 100, height: 70)
imageLayer.contents = UIImage(named: "first_image")?.cgImage

let animation = CABasicAnimation()
animation.keyPath = "position.x"
animation.fromValue = 100
animation.toValue = 300
animation.duration = 3
animation.fillMode = kCAFillModeForwards
animation.isRemovedOnCompletion = true
animation.repeatCount = 2
imageLayer.add(animation, forKey: "basic")

self.view.layer.addSublayer(imageLayer)

我想做的是，在

Cycle: 1 - "first_image" will move from left to right

并在

Cycle: 2 - "second_image" (this is another image) will move from left to right like previous cycle.

这里Cycle: 1 + Cycle: 2实际上是一个动画，我希望这个动画发生多次。如何实现这一目标？任何帮助将不胜感激。

Answer 1

由于您需要从左到右的动画，反之亦然，您还可以使用 UIView.anima.. 进行动画。

     let testViewTowardsLeft = UIView(frame: CGRect(x: 0, y: 150, width: 50, height: 50))
    testViewTowardsLeft.backgroundColor = .red
    view.addSubview(testViewTowardsLeft)
    UIView.animate(withDuration: 1, delay: 0, options: .repeat, animations: {Bool in
        testViewTowardsLeft.frame = CGRect(x: 100, y: 150, width: 50, height: 50)

    }, completion: nil)


    let testViewTowardsRight = UIView(frame: CGRect(x: 100, y: 100, width: 50, height: 50))
    testViewTowardsRight.backgroundColor = .red
    view.addSubview(testViewTowardsRight)
    UIView.animate(withDuration: 1, delay: 0, options: .repeat, animations: {Bool in
        testViewTowardsRight.frame = CGRect(x: 0, y: 100, width: 50, height: 50)

    }, completion: nil)