Xcode 8.3.2操場實時視圖渲染不起作用

此代碼在以前版本的Xcode中完美工作，但現在它不顯示任何內容。它只顯示活動指標，說「正在運行的項目」Xcode 8.3.2操場實時視圖渲染不起作用

import UIKit 
import PlaygroundSupport 

let container = UIView() 
container.frame.size = CGSize(width: 215.0, height: 215.0) 

var view = UIView() 
view.frame.size = CGSize(width: 185.0, height: 185.0) 
view.center = container.center 
view.layer.cornerRadius = view.frame.size.height/2 
view.backgroundColor = UIColor.white 

container.addSubview(view) 

let scaleAnimation = CABasicAnimation(keyPath: "transform.scale") 
scaleAnimation.fromValue = CGFloat(0.6) 
scaleAnimation.toValue = CGFloat(1.15) 
scaleAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut) 
scaleAnimation.isRemovedOnCompletion = false 

let opacityAnimation = CABasicAnimation(keyPath: "opacity") 
opacityAnimation.fromValue = CGFloat(0.0) 
opacityAnimation.toValue = CGFloat(0.1) 
opacityAnimation.duration = 1 
opacityAnimation.isRemovedOnCompletion = false 
opacityAnimation.autoreverses = true; 


let circleAnimations: CAAnimationGroup = CAAnimationGroup() 
circleAnimations.duration = 2 
circleAnimations.repeatCount = HUGE; 
circleAnimations.animations = [scaleAnimation, opacityAnimation]; 

view.layer .add(circleAnimations, forKey: "circleAnimations") 

PlaygroundPage.current.liveView = container 
PlaygroundPage.current.needsIndefiniteExecution = true

它有什麼問題呢？

來源

2017-04-27 Alexey K

Xcode 8.3.2（8E2002），它工作得很好。在macOS上測試10.12.4（16E195） –