无法更改视图背景颜色

Question

I have this base class BaseController where I change the view background color

self.view.backgroundColor = 
    UIColor(red: 0/255, green: 255/255, blue: 0/255, alpha: 0)

in the viewDidLoad() method

import UIKit

class BaseController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = UIColor(red: 0/255, green: 255/255, blue: 0/255, alpha: 0)

    }

    func UIColorFromHex(rgbValue:UInt32, alpha:Double=1.0)->UIColor {
        let red = CGFloat((rgbValue & 0xFF0000) >> 16)/256.0
        let green = CGFloat((rgbValue & 0xFF00) >> 8)/256.0
        let blue = CGFloat(rgbValue & 0xFF)/256.0

        return UIColor(red:red, green:green, blue:blue, alpha:CGFloat(alpha))
    }
}

And here is MainController which extends BaseController and is my entry point

import UIKit

class MainController: BaseController {
    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = UIColor(red: 0/255, green: 37/255, blue: 0/255, alpha: 0)
    }
}

But the background color of MainController view doesn't change, except when I manually select a color on the utilities pane.

How do I change the background color dynamically using the parent class?

Answer 1

您的 alpha 值在两个 backgroundColor 分配中都设置为 0，这将使颜色完全清晰