ios - 当我更改 ViewController 时 UIImageView 不旋转

Question

我在 ViewController 中有一个旋转的 UIImageView。但是，当我将 ViewController 更改为 SecondViewController 并将 SecondViewController 更改为 ViewController 时，UIImageView 不会旋转。

扩展；

import Foundation
import UIKit

extension UIView {

    //Start Rotating view
    func startRotating(duration: Double = 1) {
        let kAnimationKey = "rotation"

        if self.layer.animation(forKey: kAnimationKey) == nil {
            let animate = CABasicAnimation(keyPath: "transform.rotation")
            animate.duration = duration
            animate.repeatCount = Float.infinity

            animate.fromValue = 0.0
            animate.toValue = Float(Double.pi * 2.0)
            self.layer.add(animate, forKey: kAnimationKey)
        }
    }

    //Stop rotating view
    func stopRotating() {
        let kAnimationKey = "rotation"

        if self.layer.animation(forKey: kAnimationKey) != nil {
            self.layer.removeAnimation(forKey: kAnimationKey)
        }
    }

}


viewdidload ;

logo.startRotating(duration: 6)

Answer 1

Kerim Sener 在您的旋转代码中没有任何问题，只是调用 View 中的函数确实出现了如下所示的方法......在您的 View Controller 中。

override func viewDidAppear(_ animated: Bool) {
        logo.startRotating(duration: 6)
    }