自动启动描边结束动画

Question

我有一个画圆的动画。我结合了 3 种不同的圆形动画来创建风格化的图形/饼图。

它们在按钮的@IBAction中制作完美的动画。但是，当故事板/视图控制器被打开/导航到时，我将如何自动启动动画？

动画代码如下：

    //NF Colour
    let colorNF = UIColor(red: 28/255, green: 117/255, blue: 189/255, alpha: 1)
    // Create Holding Rectangle and Start and End Angles
    let ovalStartAngleNF = CGFloat(-90.01 * .pi/180)
    let ovalEndAngleNF = CGFloat(10.0 * .pi/180)
    let ovalRectNF = CGRect(origin: CGPoint(x: 122.5,y: 83.5), size: CGSize(width: 100, height: 100))
    // Create Bezier Path
    let ovalPathNF = UIBezierPath()
    // Apply Attributes to Bezier Path
    ovalPathNF.addArc(withCenter: CGPoint(x: ovalRectNF.midX, y: ovalRectNF.midY),
                      radius: ovalRectNF.width / 2,
                      startAngle: ovalStartAngleNF,
                      endAngle: ovalEndAngleNF, clockwise: true)
    // Styling of the Curve
    let progressLineNF = CAShapeLayer()
    progressLineNF.path = ovalPathNF.cgPath
    progressLineNF.strokeColor = colorNF.cgColor
    progressLineNF.fillColor = UIColor.clear.cgColor
    progressLineNF.lineWidth = 20.0
    progressLineNF.lineCap = kCALineCapRound
    // Add Curve to Viewport
    self.view.layer.addSublayer(progressLineNF)
    // Animated the 'Stroke End' from 0 to 1 over 3 Seconds
    let animateStrokeEndNF = CABasicAnimation(keyPath: "strokeEnd")
    animateStrokeEndNF.duration = 3.0
    animateStrokeEndNF.fromValue = 0.0
    animateStrokeEndNF.toValue = 1.0
    // Add the Animation to the Progress Line
    progressLineNF.add(animateStrokeEndNF, forKey: "animate stroke end animation")

Answer 1

正如乔在评论中所说。解决方案是将我的动画代码放入viewWillAppear中。

 override func viewWillAppear(_ animated: Bool) { *ANIMATION CODE* }