我正在尝试在视图控制器中制作动画,其中圆圈随动画旋转。圆圈应该旋转,直到一个过程像下面的gif一样完成。我已经实现了圆形动画,但无法达到我想达到的目的。
kmeans_data
我正在使用strokeEnd动画来实现动画。并且不透明度可以为颜色设置动画。但是当圆圈达到360度时,它会在开始新圆圈之前产生延迟。
有人知道如何移除此效果并获得流畅的动画吗?
The above code produces this animation
But i want to achieve this animation
笔画颜色也与原始动画不同。我们可以使用CABasicAnimation来实现这个动画吗?
答案 0 :(得分:5)
不是试图为实际绘图设置动画,只需绘制一次视图,然后为其设置动画。
这是一个自定义PadlockView
和一个自定义CircleView
,它模仿您展示的动画。要使用它,请将以下代码添加到项目中。在您的故事板中添加UIView
,将其类更改为PadlockView
,并为其创建@IBOutlet
(也许称为padlock
)。如果希望视图设置动画,请设置padlock.circle.isAnimating = true
。要停止制作动画,请设置padlock.circle.isAnimating = false
。
<强> CircleView.swift 强>
// This UIView extension was borrowed from @keval's answer:
// https://stackoverflow.com/a/41160100/1630618
extension UIView {
func rotate360Degrees(duration: CFTimeInterval = 3) {
let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
rotateAnimation.fromValue = 0.0
rotateAnimation.toValue = CGFloat.pi * 2
rotateAnimation.isRemovedOnCompletion = false
rotateAnimation.duration = duration
rotateAnimation.repeatCount = Float.infinity
self.layer.add(rotateAnimation, forKey: nil)
}
}
class CircleView: UIView {
var foregroundColor = UIColor.white
var lineWidth: CGFloat = 3.0
var isAnimating = false {
didSet {
if isAnimating {
self.isHidden = false
self.rotate360Degrees(duration: 1.0)
} else {
self.isHidden = true
self.layer.removeAllAnimations()
}
}
}
override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
func setup() {
self.isHidden = true
self.backgroundColor = .clear
}
override func draw(_ rect: CGRect) {
let width = bounds.width
let height = bounds.height
let radius = (min(width, height) - lineWidth) / 2.0
var currentPoint = CGPoint(x: width / 2.0 + radius, y: height / 2.0)
var priorAngle = CGFloat(360)
for angle in stride(from: CGFloat(360), through: 0, by: -2) {
let path = UIBezierPath()
path.lineWidth = lineWidth
path.move(to: currentPoint)
currentPoint = CGPoint(x: width / 2.0 + cos(angle * .pi / 180.0) * radius, y: height / 2.0 + sin(angle * .pi / 180.0) * radius)
path.addArc(withCenter: CGPoint(x: width / 2.0, y: height / 2.0), radius: radius, startAngle: priorAngle * .pi / 180.0 , endAngle: angle * .pi / 180.0, clockwise: false)
priorAngle = angle
foregroundColor.withAlphaComponent(angle/360.0).setStroke()
path.stroke()
}
}
}
<强> PadlockView.swift 强>
class PadlockView: UIView {
var circle: CircleView!
override init(frame: CGRect) {
super.init(frame: frame)
setup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
func setup() {
self.backgroundColor = .clear
circle = CircleView()
circle.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(circle)
circle.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
circle.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
circle.widthAnchor.constraint(equalTo: self.widthAnchor).isActive = true
circle.heightAnchor.constraint(equalTo: self.heightAnchor).isActive = true
}
override func draw(_ rect: CGRect) {
let width = bounds.width
let height = bounds.height
let lockwidth = width / 3
let lockheight = height / 4
let boltwidth = lockwidth * 2 / 3
UIColor.white.setStroke()
let path = UIBezierPath()
path.move(to: CGPoint(x: (width - lockwidth) / 2, y: height / 2))
path.addLine(to: CGPoint(x: (width + lockwidth) / 2, y: height / 2))
path.addLine(to: CGPoint(x: (width + lockwidth) / 2, y: height / 2 + lockheight))
path.addLine(to: CGPoint(x: (width - lockwidth) / 2, y: height / 2 + lockheight))
path.close()
path.move(to: CGPoint(x: (width - boltwidth) / 2, y: height / 2))
path.addLine(to: CGPoint(x: (width - boltwidth) / 2, y: height / 2 - boltwidth / 4))
path.addArc(withCenter: CGPoint(x: width/2, y: height / 2 - boltwidth / 4), radius: boltwidth / 2, startAngle: .pi, endAngle: 0, clockwise: true)
path.lineWidth = 2.0
path.stroke()
}
}
注意:连续动画代码由this answer提供。
以下是我在ViewController
中使用以下代码设置的演示:
@IBOutlet weak var padlock: PadlockView!
@IBAction func startStop(_ sender: UIButton) {
if sender.currentTitle == "Start" {
sender.setTitle("Stop", for: .normal)
padlock.circle.isAnimating = true
} else {
sender.setTitle("Start", for: .normal)
padlock.circle.isAnimating = false
}
}