ios - Swift3 中的 UIView 动画

Question

我正在尝试将 UIImageView 移动到顶部、底部、左侧和右侧。动画应该是4四次。中心图像向顶部移动，然后向左位置和向右位置移动。如何使用 UIAnimation swift 3 实现此目的？

UIView.animate(withDuration: 0.1, 
               delay:0, 
               animations: {}, 
               completion: {completion in})

如何使用动画将图像移动到顶部、左侧、右侧和底部？

Answer 1

您应该为此使用关键帧动画，因为它允许您指定动画的顺序。下面是一个基本示例:

let animationDuration = 2.0
let position: CGFloat = 50.0
let viewToAnimate = UIImageView()

UIView.animateKeyframes(withDuration: animationDuration, delay: 0.0, options: .calculationModeLinear, animations: {
    UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 1/3, animations: {
        viewToAnimate.frame.origin.y = viewToAnimate.frame.origin.y + position
    })
    UIView.addKeyframe(withRelativeStartTime: 1/4, relativeDuration: 1/4, animations: {
        viewToAnimate.frame.origin.y = viewToAnimate.frame.origin.y - (position * 2)
    })
    UIView.addKeyframe(withRelativeStartTime: 2/4, relativeDuration: 1/4, animations: {
        viewToAnimate.frame.origin.x = viewToAnimate.frame.origin.x - position
    })
    UIView.addKeyframe(withRelativeStartTime: 3/4, relativeDuration: 1/4, animations: {
        viewToAnimate.frame.origin.x = viewToAnimate.frame.origin.x + (position * 2)
    })
}, completion: { completed in

})