swift UIView animateWithDuration 与重复和自动反转答案

【问题标题】：swift UIView animateWithDuration with repeat and autoreverseswift UIView animateWithDuration 与重复和自动反转
【发布时间】：2016-01-10 19:36:57
【问题描述】：

我是 swift 新手，这是我有史以来的第一个问题.... 我想缩小一个持续时间为 2 秒的球，然后将其扩大 5 秒。我的问题是第二个持续时间被忽略（球缩小 2 秒并增长 2 秒）。我希望有人可以帮助我。

这是我的尝试：

    let ball = UIView()
    ball.frame = CGRectMake(50, 50, 50, 50)
    ball.backgroundColor = UIColor.blueColor()
    ball.layer.cornerRadius=25
    relaxContainer.addSubview(ball)

    UIView.animateWithDuration(2.0, delay:0, options: [.Repeat, .Autoreverse], animations: {
        ball.frame = CGRectMake(50, 50, 20, 20)
        }, completion: { finished in
            UIView.animateWithDuration(5.0, animations: {
                ball.frame = CGRectMake(50, 50, 50, 50)
            })
    })

【问题讨论】：

标签： ios swift animation animatewithduration

【解决方案1】：

感谢 Matt 的帮助，我的答案（持续时间、原始问题的变量已更改）：

斯威夫特 2

let duration = 6.0
let delay = 0.0
UIView.animateKeyframesWithDuration(duration, delay: delay, options: [.Repeat], animations: {
    UIView.addKeyframeWithRelativeStartTime(0, relativeDuration: 1/3, animations: {
        ball.frame = CGRectMake(screenWidth/8*3, screenHeight/8*3, screenWidth/4, screenWidth/4)
    })
    UIView.addKeyframeWithRelativeStartTime(1/3, relativeDuration: 2/3, animations: {
        ball.frame = CGRectMake(screenWidth/4, screenHeight/4, screenWidth/2, screenWidth/2)
    })
    }, completion: nil
)

斯威夫特 3、4、5

let duration = 6.0
let delay = 0.0
UIView.animateKeyframes(withDuration: duration, delay: delay, options: [.repeat], animations: {
    UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 1/3, animations: {
        ball.frame = CGRect(x: screenWidth/8*3, y: screenHeight/8*3, width: screenWidth/4, height: screenWidth/4)
    })
    UIView.addKeyframe(withRelativeStartTime: 1/3, relativeDuration: 2/3, animations: {
        ball.frame = CGRect(x: screenWidth/4, y: screenHeight/4, width: screenWidth/2, height: screenWidth/2)
    })
    }, completion: nil
)

【讨论】：

如果你不使用它，记得把你的完成块清零，以保持你的代码干净:)