ios - 为什么我的 NSNotificationCenter 抛出异常？

Question

我有一个带有滑动手势识别器的 TableView Controller ，它会在用户向上滑动时触发 NSNotificationCenter.defaultCenter().postNotificationName("DuskTheme", object: nil)。

在 viewDidLoad() 函数中，我有以下观察者:NSNotificationCenter.defaultCenter().addObserver(self, selector: "dusk:", name:"DuskTheme", object: nil)它调用函数 dusk(notification: NSNotification) 改变当前 View Controller (即主题)上元素的颜色。

我想在用户滑动时更改导航栏的颜色，所以我将 navigationController 子类化并将以下观察器添加到它的 viewDidLoad() 中:NSNotificationCenter.defaultCenter().addObserver(self, selector : "dusk:", name:"DuskTheme", object: nil) 以及 dusk(notification: NSNotification) 函数包含我链接的导航栏的新颜色 Storyboard。

这是我的自定义导航 Controller 类:

class customNavigationController: UINavigationController {
    @IBOutlet weak var featuredNavBar = ThemeManager.navigationbar

    override func viewDidLoad() {
        super.viewDidLoad()
        //Adding a theme notification observer
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "dusk:", name:"DuskTheme", object: nil)

        func dusk(notification: NSNotification) {
            UIView.animateWithDuration(1, animations: {
                UIApplication.sharedApplication().statusBarStyle = .LightContent
                self.featuredNavBar?.barTintColor = UIColor(red: 69/255, green: 69/255, blue: 69/255, alpha: 1)

            })
        }

    }

}

现在由于某种原因，每当滑动 TableView Controller 时，应用程序都会抛出以下异常:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[TestApp.customNavigationController dusk:]: unrecognized selector sent to instance 0x7939c910'

这个错误是由手势识别器引起的吗？在对导航 Controller 进行子类化之前，它工作正常。更重要的是，检测主题已更改并更改导航栏颜色的更好方法是什么？

提前致谢!

Answer 1

将 dusk() 移到 viewDidLoad() 之外。它需要在顶层:

class customNavigationController: UINavigationController {
    @IBOutlet weak var featuredNavBar = ThemeManager.navigationbar

    func dusk(notification: NSNotification) {
        UIView.animateWithDuration(1, animations: {
            UIApplication.sharedApplication().statusBarStyle = .LightContent
            self.featuredNavBar?.barTintColor = UIColor(red: 69/255, green: 69/255, blue: 69/255, alpha: 1)

        })
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        //Adding a theme notification observer
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "dusk:", name:"DuskTheme", object: nil)
    }
}