colorWithRed

backgroundColor=UIColor .colorWithRed(125/255.0, green: 125/255.0, blue: 125/255.0, alpha: 1.0)  
改为
backgroundColor = UIColor(red: 0.5, green: 0.5, blue: 0.5, alpha: 1.0)  

或者
import Foundation
import UIKit

extension UIColor {
    convenience init(rgb: UInt) {
        self.init(
            red: CGFloat((rgb & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((rgb & 0x00FF00) >> 8) / 255.0,
            blue: CGFloat(rgb & 0x0000FF) / 255.0,
            alpha: CGFloat(1.0)
        )
    }
}