如何在Swift中使用带日期而不是数字的范围滑块？

import UIKit

class DateRangeSlider: UISlider {
    var minDate: Date!
    var maxDate: Date!
    var currentDate: Date!
    
    func setupSlider(minDate: Date, maxDate: Date) {
        self.minDate = minDate
        self.maxDate = maxDate
        
        self.minimumValue = Float(minDate.timeIntervalSince1970)
        self.maximumValue = Float(maxDate.timeIntervalSince1970)
        
        self.currentDate = minDate
        self.value = Float(minDate.timeIntervalSince1970)
    }
    
    func updateDate() {
        let interval = TimeInterval(self.value)
        self.currentDate = Date(timeIntervalSince1970: interval)
    }
    
    func formatDate() -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd"
        return formatter.string(from: self.currentDate)
    }
}