ios - UIBezierPath 动画 - 对象固定在左上角
问题描述
我正在尝试快速创建一个动画,以使一些气球从屏幕底部浮动到顶部。然而,在动画的中间,一个气球固定在屏幕的左上角,即使动画结束也不会消失。
请观看此视频以了解我在说什么:
这是我的代码。我真的不知道我做错了什么。
func presentVictoryView() {
blackView.isHidden = false
for _ in 0 ... 20 {
let objectView = UIView()
objectView.translatesAutoresizingMaskIntoConstraints = false
objectView.frame = CGRect(x: 50, y: 50, width: 20, height: 100)
//objectView.backgroundColor = .clear
//objectView.alpha = CGFloat(0.9)
objectView.isHidden = false
let ballon = UILabel()
ballon.translatesAutoresizingMaskIntoConstraints = false
ballon.frame = CGRect(x: 50, y: 50, width: 20, height: 100)
//ballon.backgroundColor = .clear
//ballon.alpha = CGFloat(0.9)
ballon.text = ""
ballon.font = UIFont.systemFont(ofSize: 60)
objectView.addSubview(ballon)
NSLayoutConstraint.activate([
ballon.centerXAnchor.constraint(equalTo: objectView.centerXAnchor),
ballon.centerYAnchor.constraint(equalTo: objectView.centerYAnchor)
])
blackView.addSubview(objectView)
let randomXOffset = Int.random(in: -120 ..< 200)
let path = UIBezierPath()
path.move(to: CGPoint(x: 270 + randomXOffset, y: 1000))
path.addCurve(to: CGPoint(x: 100 + randomXOffset, y: -300), controlPoint1: CGPoint(x: 300 - randomXOffset, y: 600), controlPoint2: CGPoint(x: 70 + randomXOffset, y: 300))
let animation = CAKeyframeAnimation(keyPath: "position")
animation.path = path.cgPath
animation.repeatCount = 1
animation.duration = Double.random(in: 4.0 ..< 7.0)
//animation.timeOffset = Double(arc4random_uniform(50))
objectView.layer.add(animation, forKey: "animate position along path")
}
//objectView.isHidden = true
//self?.newGame()
}
谢谢您的帮助!:)
解决方案
您应该使用委托来检测动画的结束并删除bubbleView。
func presentVictoryView() {
blackView.isHidden = false
for _ in 0 ... 20 {
let objectView = UIView()
objectView.translatesAutoresizingMaskIntoConstraints = false
objectView.frame = CGRect(x: 50, y: 50, width: 20, height: 100)
//objectView.backgroundColor = .clear
//objectView.alpha = CGFloat(0.9)
objectView.isHidden = false
let ballon = UILabel()
ballon.translatesAutoresizingMaskIntoConstraints = false
ballon.frame = CGRect(x: 50, y: 50, width: 20, height: 100)
//ballon.backgroundColor = .clear
//ballon.alpha = CGFloat(0.9)
ballon.text = ""
ballon.font = UIFont.systemFont(ofSize: 60)
objectView.addSubview(ballon)
NSLayoutConstraint.activate([
ballon.centerXAnchor.constraint(equalTo: objectView.centerXAnchor),
ballon.centerYAnchor.constraint(equalTo: objectView.centerYAnchor)
])
blackView.addSubview(objectView)
let randomXOffset = Int.random(in: -120 ..< 200)
let path = UIBezierPath()
path.move(to: CGPoint(x: 270 + randomXOffset, y: 1000))
path.addCurve(to: CGPoint(x: 100 + randomXOffset, y: -300), controlPoint1: CGPoint(x: 300 - randomXOffset, y: 600), controlPoint2: CGPoint(x: 70 + randomXOffset, y: 300))
let animation = CAKeyframeAnimation(keyPath: "position")
animation.path = path.cgPath
animation.repeatCount = 1
// add these
animation.fillMode = .forwards
animation.isRemovedOnCompletion = false
let delegate = BubbleAnimDelegate()
delegate.didFinishAnimation = {
objectView.removeFromSuperview()
}
animation.delegate = delegate
// upto here
animation.duration = Double.random(in: 4.0 ..< 7.0)
//animation.timeOffset = Double(arc4random_uniform(50))
objectView.layer.add(animation, forKey: "animate position along path")
}
//objectView.isHidden = true
//self?.newGame()
}
class BubbleAnimDelegate: NSObject, CAAnimationDelegate {
var didFinishAnimation: (()->Void)?
func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
didFinishAnimation?()
}
}
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