iOS:以百分比形式在UIView中绘制圆

import UIKit

class PercentageCircleView: UIView {
    
    var percentage: CGFloat = 0.0 {
        didSet {
            setNeedsDisplay() // 当百分比改变时重绘视图
        }
    }
    
    override func draw(_ rect: CGRect) {
        guard let context = UIGraphicsGetCurrentContext() else { return }
        
        // 设置圆心和半径
        let center = CGPoint(x: rect.width / 2, y: rect.height / 2)
        let radius = min(rect.width, rect.height) / 2
        
        // 绘制背景圆
        context.setStrokeColor(UIColor.lightGray.cgColor)
        context.setLineWidth(10)
        context.addArc(center: center, radius: radius, startAngle: .pi * 1.5, endAngle: .pi * 1.5 + .pi * 2, clockwise: true)
        context.strokePath()
        
        // 绘制百分比圆
        context.setStrokeColor(UIColor.blue.cgColor)
        let endAngle = .pi * 1.5 + .pi * 2 * percentage
        context.addArc(center: center, radius: radius, startAngle: .pi * 1.5, endAngle: endAngle, clockwise: true)
        context.strokePath()
    }
}