ios - UIView animate - 旋转并放大，然后旋转并缩小

Question

我有一个子类 ImageView ，我想淡入、放大和旋转，然后继续旋转，同时缩小和淡出。

我正在使用带有完成处理程序的 UIView 动画 block 来处理收缩。

问题在于它不是流畅的动画。在完成处理程序运行之前，动画会在再次运行之前停止。我需要它是一个漂亮的动画“俯冲”。

代码如下:

    let duration: TimeInterval = 3.0
    let rotate = CGAffineTransform(rotationAngle: CGFloat(Double.pi))


    UIView.animate(withDuration: duration * 3, delay: 0, options: [.curveLinear], animations: {
        // initial transform
        self.alpha = 0
        self.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)
        // initial spin for duration of animaton
        UIView.animate(withDuration: duration * 3, delay: 0.0, options: [.curveLinear], animations: {
            self.transform = rotate
        }, completion: nil)

        // scaling and fading
        UIView.animate(withDuration: duration, delay: 0, options: [.curveLinear], animations: {
            UIView.setAnimationRepeatCount(3)
            self.transform = self.transform.scaledBy(x: 0.8, y: 0.8)
            self.alpha = 1
        }) { (true) in
            UIView.animate(withDuration: duration, animations: {
                UIView.setAnimationRepeatCount(3)
                self.transform = self.transform.scaledBy(x: 0.1, y: 0.1)
                self.alpha = 0
            })
        }
    }, completion: nil)

如何让动画在淡入和放大之前一直旋转，然后再缩小和淡出？整个动画应持续 3 秒，并重复 3 次。谢谢。

Answer 1

对于您修改后的请求，我正在使用 block 动画扩展您已经看到的内容。正如一些人所说，无论如何，关键帧动画可能会更好，这是我的想法。

创建一个通过变换 View 来旋转整个时间的动画。 创建另一个基于当前变换(正在旋转)进行缩放和淡入淡出的动画。在此过程中，我刚刚创建了一些变量以允许您自定义(和重复)动画的某些部分。我打破了一些东西是为了清楚，并且知道我可以重构来写得更简洁。

这是代码

import UIKit

class OrangeView: UIView {



override func layoutSubviews() {
    super.layoutSubviews()

  let duration: TimeInterval = 9.0

  self.transform = CGAffineTransform.identity

  // initial transform
  self.alpha = 1
  self.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)

  // start rotation
  rotate(duration: duration)

  // scaling and fading
  scaleUpAndDown(desiredRepetitions: 3, initalDuration: duration)


  }

func rotate(duration: TimeInterval) {
                UIView.animate(withDuration: duration/2.0,
                               delay: 0.0,
                               options: [.curveLinear], animations: {
                                let angle = Double.pi
                                self.transform = self.transform.rotated(by: CGFloat(angle))
                }, completion: {[weak self] finished in
  guard let strongSelf = self else {
    return
  }
  if finished &&
    strongSelf.transform != CGAffineTransform.identity {
    strongSelf.rotate(duration: duration)
  } else {
    // rotation ending
  }
})

  }

func scaleUpAndDown(timesRepeated: Int = 0, desiredRepetitions: Int, initalDuration: TimeInterval) {

guard timesRepeated < desiredRepetitions,
  desiredRepetitions > 0, initalDuration > 0 else {
  self.transform = CGAffineTransform.identity
    return
}
let repeatedCount = timesRepeated + 1

let scalingDuration = initalDuration/2.0/Double(desiredRepetitions)

UIView.animate(withDuration: scalingDuration,
               delay: 0.0,
               animations: {
                let desiredOriginalScale: CGFloat = 0.8

                let scaleX = abs(CGAffineTransform.identity.a / self.transform.a) * desiredOriginalScale
                let scaleY = abs(CGAffineTransform.identity.d / self.transform.d) * desiredOriginalScale

                self.transform = self.transform.scaledBy(x: scaleX, y: scaleY)
                self.alpha = 1
              }) { (true) in
                UIView.animate(withDuration:scalingDuration,
                               delay: 0.0,
                               animations: {

                                let desiredOriginalScale: CGFloat = 0.1

                                let scaleX = abs(CGAffineTransform.identity.a / self.transform.a) * desiredOriginalScale
                                let scaleY = abs(CGAffineTransform.identity.d / self.transform.d) * desiredOriginalScale
                                  self.transform = self.transform.scaledBy(x: scaleX, y: scaleY)
                                  self.alpha = 0
                }) { finshed in
                  self.scaleUpAndDown(timesRepeated: repeatedCount, desiredRepetitions: desiredRepetitions, initalDuration: initalDuration);
                }
              }

  }

}

最后来一张动图