我有这个循环进度 View 的代码，它显示了你通过计时器的进度，例如您将计时器设置为 60 秒，当您达到 30 秒时进度条就在中间。代码如下所示:

import UIKit

class TimerCircularProgressView: UIView {

@IBInspectable var timeSeconds:CGFloat = CGFloat(timers.seconds[timers.timerID]) {
    didSet {
        setNeedsDisplay()
    }
}

@IBInspectable var timeLabelString:String = "" {
    didSet {
        setNeedsDisplay()
    }
}


private var startAngle = CGFloat(-90 * Double.pi / 180)
private var endAngle = CGFloat(270 * Double.pi / 180)

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

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

private func setup() {
    backgroundColor = .clear
}

override func draw(_ rect: CGRect) {
    // General Declarations
    guard let context = UIGraphicsGetCurrentContext() else {
        return
    }

    // Colour Declarations
    let progressColour = UIColor(red: 1, green: 1, blue: 1, alpha: 1)
    let progressBackgroundColour = UIColor(red: 1, green: 1, blue: 1, alpha: 0.4)
    // let titleColour = UIColor(red: 1, green: 1, blue: 1, alpha: 0.8) // let titleColour = UIColor(red: 1, green: 1, blue: 1, alpha: 0.8)

    // Shadow Declarations
    let innerShadow = UIColor.black.withAlphaComponent(0.22)
    let innerShadowOffset = CGSize(width: 3.1, height: 3.1)
    let innerShadowBlurRadius = CGFloat(4)

    // Background Drawing
    let backgroundPath = UIBezierPath(ovalIn: CGRect(x: rect.minX, y: rect.minY, width: rect.width, height: rect.height))
    backgroundColor?.setFill()
    backgroundPath.fill()

    // ProgressBackground Drawing
    let progressPadding = CGFloat(timers.deviceWidth / 32 * 1.5) // 15
    print(progressPadding)
    print(timers.deviceWidth)

    let progressBackgroundPath = UIBezierPath(ovalIn: CGRect(x: rect.minX + progressPadding/2, y: rect.minY + progressPadding/2, width: rect.size.width - progressPadding, height: rect.size.height - progressPadding))
    progressBackgroundColour.setStroke()
    progressBackgroundPath.lineWidth = timers.deviceWidth / 32 // 5, 10
    progressBackgroundPath.stroke()

    // Progress Drawing
    let progressRect = CGRect(x: rect.minX + progressPadding/2, y: rect.minY + progressPadding/2, width: rect.size.width - progressPadding, height: rect.size.height - progressPadding)
    let progressPath = UIBezierPath()
    progressPath.addArc(withCenter: CGPoint(x: progressRect.midX, y: progressRect.midY), radius: progressRect.width / 2, startAngle: startAngle, endAngle: (endAngle - startAngle) * (CGFloat(timers.seconds[timers.timerID]/timers.seconds[timers.timerID])  - (timeSeconds / CGFloat(timers.seconds[timers.timerID]))) + startAngle, clockwise: true)
    progressColour.setStroke()
    progressPath.lineWidth = timers.deviceWidth / 32 * 0.8 // Thickness of the progress line
    progressPath.lineCapStyle = CGLineCap.round
    progressPath.stroke()

    // Text Drawing
    let textRect = CGRect(x: rect.minX, y: rect.minY, width: rect.size.width, height: rect.size.height)
    let textContent = NSString(string: timeLabelString)
    let textStyle = NSMutableParagraphStyle.default.mutableCopy() as! NSMutableParagraphStyle
    textStyle.alignment = .center

    let textFontAttributes = [
        NSAttributedStringKey.font: UIFont(name: "Helvetica", size: rect.width / timers.timerFontSize)!, // 3, HelveticaNeue-Light
        NSAttributedStringKey.foregroundColor: UIColor.black, // NSAttributedStringKey.foregroundColor: titleColor,
        NSAttributedStringKey.paragraphStyle: textStyle]

    let textHeight = textContent.boundingRect(with: CGSize(width: textRect.width, height: textRect.height), options: .usesLineFragmentOrigin, attributes: textFontAttributes, context: nil).height

    context.saveGState()
    context.clip(to: textRect)
    textContent.draw(in: CGRect(x: textRect.minX, y: textRect.minY + (textRect.height - textHeight) / 2, width: textRect.width, height: textHeight), withAttributes: textFontAttributes)
    context.restoreGState();
}

}

目前，圆形进度条每秒更新一次，这意味着在短时间内，进度条移动的动画会跳动，不流畅。

我已经尝试设置一个大约 0.05 秒间隔的计时器，但这可能会导致计时不准确，所以我尝试了 0.1 和 0.2，它们仍然显得相当不稳定。

@objc func processSlider() {

    if secondsDDecimal > 0 {
        secondsDDecimal -= 0.2
    }

    circularProgressView.timeSeconds = CGFloat(secondsDDecimal)

}

有没有一种方法可以让循环进度 View 的过渡动画一秒一秒，使其平滑而不跳跃？