iOS UISlider自定义.从中心显示突出显示

import UIKit

class CustomSlider: UISlider {
    override func layoutSubviews() {
        super.layoutSubviews()
        
        if let thumbView = self.subviews.last {
            let thumbSize = thumbView.frame.size
            let trackRect = self.trackRect(forBounds: self.bounds)
            let thumbRect = thumbView.frame
            
            let thumbOriginX = (trackRect.size.width - thumbSize.width) / 2.0
            let thumbOriginY = (trackRect.size.height - thumbSize.height) / 2.0
            thumbView.frame = CGRect(x: thumbOriginX, y: thumbOriginY, width: thumbSize.width, height: thumbSize.height)
            
            // 设置滑块的外观，例如颜色、背景图像等
            thumbView.backgroundColor = UIColor.red
            thumbView.layer.cornerRadius = thumbSize.height / 2.0
        }
    }
}

// 在使用时，可以像使用普通的UISlider一样使用CustomSlider
let slider = CustomSlider(frame: CGRect(x: 0, y: 0, width: 200, height: 20))
slider.minimumValue = 0
slider.maximumValue = 100
slider.value = 50

// 添加到视图中显示
view.addSubview(slider)