我们也应该删除通知。

Ex.

deinit 
{
  NotificationCenter.default.removeObserver(self, name:NSNotification.Name(rawValue: "notify"), object: nil)

}

Swift 5通知观察员

override func viewDidLoad() {
    super.viewDidLoad() 
    NotificationCenter.default.addObserver(self, selector: #selector(batteryLevelChanged), name: UIDevice.batteryLevelDidChangeNotification, object: nil)
}

@objc func batteryLevelChanged(notification : NSNotification){
    //do here code
}

override func viewWillDisappear(_ animated: Bool) {
    NotificationCenter.default.removeObserver(self, name: UIDevice.batteryLevelDidChangeNotification, object: nil)

}

NSNotificationCenter在iOS 11的Swift 4.0中添加了观察者语法

  NotificationCenter.default.addObserver(self, selector: #selector(keyboardShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

这是为keyboardWillShow通知名称类型。其他类型可以从可用选项中选择

选择器的类型是@objc func，它处理键盘的显示方式(这是你的用户函数)

我能够做以下之一成功地使用选择器-没有注释任何@objc:

NSNotificationCenter.defaultCenter().addObserver(self,
    selector:"batteryLevelChanged:" as Selector,
    name:"UIDeviceBatteryLevelDidChangeNotification",
    object:nil)    

OR

let notificationSelector: Selector = "batteryLevelChanged:"

NSNotificationCenter.defaultCenter().addObserver(self,
    selector: notificationSelector,
    name:"UIDeviceBatteryLevelDidChangeNotification",
    object:nil)    

我的xcrun版本显示Swift 1.2，这适用于Xcode 6.4和Xcode 7 beta 2(我认为会使用Swift 2.0):

$xcrun swift --version

Apple Swift version 1.2 (swiftlang-602.0.53.1 clang-602.0.53)

在swift 2.2 - XCode 7.3中，我们为NSNotificationCenter使用#选择器

 NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(rotate), name: UIDeviceOrientationDidChangeNotification, object: nil)

我们也应该删除通知。

Ex.

deinit 
{
  NotificationCenter.default.removeObserver(self, name:NSNotification.Name(rawValue: "notify"), object: nil)

}