圆动画滞后
圆动画滞后
提问于 2018-06-24 23:44:59
我正在用iOS制作一个圆动画，它看起来像这样：
在此动画中，当圆重复动画时，它会滞后于动画之间。我想让这个动画更流畅。
我使用清晰的视图，在其中我添加了一个圆形图层。下面是创建圆形图层的代码：
//Create circle shape layer
func setupCircle(frame: CGRect, strokeColor: CGColor)->CAShapeLayer {
let circlePath = UIBezierPath(arcCenter: CGPoint(x: frame.size.height/2, y: frame.size.height/2), radius: CGFloat((frame.size.height/2)-25), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.path = circlePath.cgPath
//change the fill color
shapeLayer.fillColor = UIColor.clear.cgColor
//you can change the stroke color
shapeLayer.strokeColor = strokeColor
//you can change the line width
shapeLayer.lineWidth = 3.0
return shapeLayer
}下面是圆形图层动画的代码：
//Add animation to circle layer
func getAnimationForCircle(frame: CGRect) -> CAAnimation {
let newPath = UIBezierPath(arcCenter: CGPoint(x: frame.size.height/2, y: frame.size.height/2), radius: CGFloat((frame.size.height/2)+25), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
let pathAnim = CABasicAnimation.init(keyPath: "path")
pathAnim.toValue = newPath.cgPath
let alphaAnimation = CABasicAnimation.init(keyPath: "opacity")
alphaAnimation.fromValue = 0.75
alphaAnimation.toValue = 0.0
let combinedAnim = CAAnimationGroup.init()
combinedAnim.animations = [pathAnim, alphaAnimation]
combinedAnim.isRemovedOnCompletion = false
combinedAnim.repeatCount = .infinity
// combinedAnim.speed = 0.2
combinedAnim.duration = 1.0
combinedAnim.fillMode = kCAFillModeBoth
return combinedAnim
}我怎样才能使这个动画流畅而没有任何延迟？
任何帮助都将不胜感激。谢谢!
回答 1
Stack Overflow用户
发布于 2018-06-25 01:21:41
我唯一的建议是使单个动画与组动画的持续时间相同，以便它们在重复次数和持续时间上匹配。我修改了不透明度，使其具有关键帧。持续时间的不同可能导致了您的口吃或滞后。
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let shapeLayer = self.setupCircle(frame: CGRect(x: 0, y: 0, width: self.view.bounds.width/2, height: self.view.bounds.width/2), strokeColor: UIColor.blue.cgColor)
let sub = UIView(frame: CGRect(x: 0, y: 0, width: self.view.bounds.width/2, height: self.view.bounds.width/2))
shapeLayer.frame = sub.bounds
sub.layer.addSublayer(shapeLayer)
sub.center = self.view.center
self.view.addSubview(sub)
let anim = self.getAnimationForCircle(frame: shapeLayer.frame)
shapeLayer.add(anim, forKey: nil)
}
//Create circle shape layer
func setupCircle(frame: CGRect, strokeColor: CGColor)->CAShapeLayer {
let circlePath = UIBezierPath(arcCenter: CGPoint(x: frame.size.height/2, y: frame.size.height/2), radius: CGFloat((frame.size.height/2)-25), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.path = circlePath.cgPath
//change the fill color
shapeLayer.fillColor = UIColor.clear.cgColor
//you can change the stroke color
shapeLayer.strokeColor = strokeColor
//you can change the line width
shapeLayer.lineWidth = 3.0
return shapeLayer
}
//Add animation to circle layer
func getAnimationForCircle(frame: CGRect) -> CAAnimation {
let newPath = UIBezierPath(arcCenter: CGPoint(x: frame.size.height/2, y: frame.size.height/2), radius: CGFloat((frame.size.height/2)+25), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
let pathAnim = CABasicAnimation.init(keyPath: "path")
pathAnim.toValue = newPath.cgPath
pathAnim.duration = 1.0
let alphaAnimation = CAKeyframeAnimation.init(keyPath: "opacity")
alphaAnimation.values = [0,0.75,0,0]
alphaAnimation.keyTimes = [0,0.1,0.87,1]
alphaAnimation.duration = 1.0
let combinedAnim = CAAnimationGroup.init()
combinedAnim.animations = [pathAnim, alphaAnimation]
combinedAnim.isRemovedOnCompletion = false
combinedAnim.repeatCount = .infinity
combinedAnim.duration = 1.0
combinedAnim.fillMode = kCAFillModeBoth
return combinedAnim
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/51011477
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