iOS 核心动画 : Show and hide effect

Question

我想使用 Core Animation 创建一个动画，例如:

• Image A is showed from 1s to 3s. After 3s, hide it.
• Image B is showed from 5s to 7s. After 7s, hide it.

我的代码:

    var animation = CABasicAnimation(keyPath: "opacity")
    animation.duration = 3.0
    // animate from fully visible to invisible
    animation.fromValue = NSNumber(float: 1.0)
    animation.toValue = NSNumber(float: 0.0)
    animation.beginTime = 2
    animation.removedOnCompletion = true
    layer1.addAnimation(animation, forKey: "animateOpacity")

    animation = CABasicAnimation(keyPath: "opacity")
    animation.duration = 3.0
    // animate from fully visible to invisible
    animation.fromValue = NSNumber(float: 1.0)
    animation.toValue = NSNumber(float: 0.0)
    animation.beginTime = 5
    animation.removedOnCompletion = true
    layer2.addAnimation(animation, forKey: "animateOpacity")

我该如何实现它？谢谢:)

Answer 1

它可以有多种方式

检查链接...<强> http://www.appcoda.com/view-animation-in-swift/

override func viewWillAppear(animated: Bool) {

    let firstImageView = UIImageView(image: UIImage(named: "bg01.png"))
    firstImageView.frame = view.frame
    view.addSubview(firstImageView)

    imageFadeIn(firstImageView)

}

func imageFadeIn(imageView: UIImageView) {

    let secondImageView = UIImageView(image: UIImage(named: "bg02.png"))
    secondImageView.frame = view.frame
    secondImageView.alpha = 0.0

    view.insertSubview(secondImageView, aboveSubview: imageView)

    UIView.animateWithDuration(2.0, delay: 2.0, options: .CurveEaseOut, animations: {
        secondImageView.alpha = 1.0
        }, completion: {_ in
            imageView.image = secondImageView.image
            secondImageView.removeFromSuperview()
    })

}