快速动画：圆形虚线加载栏？

Question

我已经在网上浏览了 2 到 3 个小时，遗憾的是找不到任何东西，（第二个问题：对 swift 不熟悉 -> 这可以忽略）

基本上我需要圆形虚线加载条：每个点都应该像圆形负载一样单独动画..

我能够制作一个圆形虚线圆圈，但无法为其设置动画...

任何帮助都将不胜感激，即使那是来自 github 的库或任何东西..

这是我创建圆形虚线圆的代码..

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
    }

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    let circlePath = UIBezierPath(arcCenter: CGPoint(x: 100,y: 100), radius: 100.0, startAngle: 0.0, endAngle:CGFloat(M_PI * 2), clockwise: true)
    let shapeLayer = CAShapeLayer()
    shapeLayer.path = circlePath.cgPath
    shapeLayer.position = CGPoint(x: 100, y: 100)
    shapeLayer.fillColor = UIColor.clear.cgColor
    shapeLayer.strokeColor = UIColor.blue.cgColor
    shapeLayer.lineWidth = 6.0
    let one : NSNumber = 1
    let two : NSNumber = 13
    shapeLayer.lineDashPattern = [one,two]
    shapeLayer.lineCap = kCALineCapRound
    view.layer.addSublayer(shapeLayer)

}
override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning()}
}

这就是我想要的（下一个）：

Answer 1

我一直在玩自定义活动指示器，所以这是一种方法

import UIKit

@IBDesignable class ActivityIndicatorCircle: UIView {
    var  timerInterval: Double   = 0.1
    var timer : Timer?
    var endAngle: CGFloat   = 0.0
    var angleStep           = CGFloat.pi / 20.0
    var angleOffset         = -CGFloat.pi / 2.0

    var shapeLayer = CAShapeLayer()

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    func startAnimating() {
        superview?.bringSubview(toFront: self)

        layer.cornerRadius = frame.width / 2
        self.clipsToBounds = true

        isHidden = false
        timer?.invalidate()
        timer = nil

        timer = Timer.scheduledTimer(timeInterval: timerInterval,
                                 target: self,
                                 selector: #selector(self.updateCircle),
                                 userInfo: nil,
                                 repeats: true)
    }

    func stopAnimating() {
        isHidden = true
        timer?.invalidate()
        timer = nil
    }

    func updateCircle() {
        endAngle += angleStep
        if endAngle > CGFloat.pi * 2.0 {
            endAngle -= CGFloat.pi * 2.0
        }
        DispatchQueue.main.async {
            self.shapeLayer.removeFromSuperlayer() // remove the previous version

            let lineWidth: CGFloat = 6.0
            let radius = self.frame.size.width / 2.0 // if the view is square, this gives us center as well

            let circlePath = UIBezierPath(arcCenter: CGPoint(x: radius,y: radius), radius: radius - lineWidth, startAngle: self.angleOffset, endAngle: self.endAngle + self.angleOffset, clockwise: true)

            self.shapeLayer.path = circlePath.cgPath
            self.shapeLayer.position = CGPoint(x: 0, y: 0)
            self.shapeLayer.fillColor = UIColor.clear.cgColor
            self.shapeLayer.strokeColor = UIColor.blue.cgColor
            self.shapeLayer.lineWidth = lineWidth
            let one : NSNumber = 1
            let two : NSNumber = 13
            self.shapeLayer.lineDashPattern = [one,two]
            self.shapeLayer.lineCap = kCALineCapRound
            self.layer.addSublayer(self.shapeLayer)
        }
    }
}

要使用它，请在情节提要中添加一个 UIView，并将类设置为 ActivityIndicatorCircle

要启动它，请致电activityIndicatorCircle.startAnimating()

Answer 2

对于循环加载器，您可以使用这个库，它将为您提供帮助。 https://github.com/naoyashiga/RPLoadingAnimation