在Swift 5中

我们说如果想从ViewControllerB接收数据到 ViewControllerA

ViewControllerA (Receiver)

import UIKit

class ViewControllerA: UIViewController  {

    override func viewDidLoad() {
        super.viewDidLoad()

        //MARK: - - - - - Code for Passing Data through Notification Observer - - - - -
        // add observer in controller(s) where you want to receive data
        NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
    }

    //MARK: - - - - - Method for receiving Data through Post Notificaiton - - - - -
    @objc func methodOfReceivedNotification(notification: Notification) {
        print("Value of notification : ", notification.object ?? "")
    }
}

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视图控制器 B （发射器）

import UIKit

class ViewControllerB: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        //MARK: - - - - - Set data for Passing Data Post Notification - - - - -
        let objToBeSent = "Test Message from Notification"
        NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
    }

}

Swift 5和Xcode 10.2:

NotificationCenter.default.addObserver(
            self,
            selector: #selector(batteryLevelDidChangeNotification),
            name: UIDevice.batteryLevelDidChangeNotification,
            object: nil)

Declare a notification name extension Notification.Name { static let purchaseDidFinish = Notification.Name("purchaseDidFinish") } You can add observer in two ways: Using Selector NotificationCenter.default.addObserver(self, selector: #selector(myFunction), name: .purchaseDidFinish, object: nil) @objc func myFunction(notification: Notification) { print(notification.object ?? "") //myObject print(notification.userInfo ?? "") //[AnyHashable("key"): "Value"] } or using block NotificationCenter.default.addObserver(forName: .purchaseDidFinish, object: nil, queue: nil) { [weak self] (notification) in guard let strongSelf = self else { return } strongSelf.myFunction(notification: notification) } func myFunction(notification: Notification) { print(notification.object ?? "") //myObject print(notification.userInfo ?? "") //[AnyHashable("key"): "Value"] } Post your notification NotificationCenter.default.post(name: .purchaseDidFinish, object: "myObject", userInfo: ["key": "Value"])

iOS 9和OS X 10.11。它不再需要一个 NSNotificationCenter观察者取消注册 收回。更多信息

对于基于块的实现，如果你想在块中使用self，你需要做一个弱-强舞蹈。更多信息

基于块的观察者需要删除更多信息

let center = NSNotificationCenter.defaultCenter()
center.removeObserver(self.localeChangeObserver)

在swift 3, Xcode 8.2:-检查电池状态水平

//Add observer
NotificationCenter.default.addObserver(self, selector: #selector(batteryStateDidChange), name: NSNotification.Name.UIDeviceBatteryStateDidChange, object: nil)


 //Fired when battery level changes

 func batteryStateDidChange(notification: NSNotification){
        //perform manipulation here
    }

Swift 4.0 & Xcode 9.0+:

发送(Post)通知:

NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: nil)

OR

NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: nil, userInfo: ["Renish":"Dadhaniya"])

得到(获得)通知:

NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)

接收到的通知的函数方法处理程序:

@objc func methodOfReceivedNotification(notification: Notification) {}

Swift 3.0 & Xcode 8.0+:

发送(Post)通知:

NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: nil)

得到(获得)通知:

NotificationCenter.default.addObserver(self, selector: #selector(YourClassName.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)

接收到的通知的方法处理程序:

func methodOfReceivedNotification(notification: Notification) {
  // Take Action on Notification
}

删除通知:

deinit {
  NotificationCenter.default.removeObserver(self, name: Notification.Name("NotificationIdentifier"), object: nil)
}

Swift 2.3和Xcode 7:

发送(Post)通知

NSNotificationCenter.defaultCenter().postNotificationName("NotificationIdentifier", object: nil)

得到(获得)通知

NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(YourClassName.methodOfReceivedNotification(_:)), name:"NotificationIdentifier", object: nil)

接收的通知的方法处理程序

func methodOfReceivedNotification(notification: NSNotification){
  // Take Action on Notification
}

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对于历史上的Xcode版本…

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发送(Post)通知

NSNotificationCenter.defaultCenter().postNotificationName("NotificationIdentifier", object: nil)

得到(获得)通知

NSNotificationCenter.defaultCenter().addObserver(self, selector: "methodOfReceivedNotification:", name:"NotificationIdentifier", object: nil)

删除通知

NSNotificationCenter.defaultCenter().removeObserver(self, name: "NotificationIdentifier", object: nil)
NSNotificationCenter.defaultCenter().removeObserver(self) // Remove from all notifications being observed

接收的通知的方法处理程序

func methodOfReceivedNotification(notification: NSNotification) {
  // Take Action on Notification
}

用@objc注释类或目标方法

@objc private func methodOfReceivedNotification(notification: NSNotification) {
  // Take Action on Notification
}

// Or

dynamic private func methodOfReceivedNotification(notification: NSNotification) {
  // Take Action on Notification
}

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)

}