如何使用Swift 3.0中的NotificationCentre和swift 2.0中的NSNotificationCenter传递数据？ [英] How to pass data using NotificationCentre in swift 3.0 and NSNotificationCenter in swift 2.0?

问题描述

我正在我的swift ios应用程序中实现 socket.io 。

I'm implementing socket.io in my swift ios app.

目前在几个面板上我正在收听服务器并等待收到的消息。我是通过在每个面板中调用 getChatMessage 函数来实现的：

Currently on several panels I'm listening to the server and wait for incoming messages. I'm doing so by calling the getChatMessage function in each panel:

func getChatMessage(){
    SocketIOManager.sharedInstance.getChatMessage { (messageInfo) -> Void in
        dispatch_async(dispatch_get_main_queue(), { () -> Void in
            //do sth depending on which panel user is
        })
    }
}

但是我注意到这是一个错误的方法，我需要改变它 - 现在我想开始倾听传入的消息只有一次，当有任何消息传来时 - 将此消息传递给任何监听它的面板。

However I noticed it's a wrong approach and I need to change it - now I want to start listening for incoming messages only once and when any message comes - pass this message to any panel that listens to it.

所以我想通过NSNotificationCenter传递传入的消息。到目前为止，我能够传递发生事件的信息，但不能传递数据本身。我是这样做的：

So I want to pass the incoming message through the NSNotificationCenter. So far I was able to pass the information that something happened, but not pass the data itself. I was doing that by:

NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ViewController.showSpinningWheel(_:)), name: showSpinner, object: nil)

然后我有一个叫做的函数：

then I had a function called:

func showSpinningWheel(notification: NSNotification) {
}

任何时候我都想打电话给我：

and any time I wanted to call it I was doing:

NSNotificationCenter.defaultCenter().postNotificationName(hideSpinner, object: self)

那么如何传递对象 messageInfo 并将其包含在被调用的函数中？

So how can I pass the object messageInfo and include it in the function that gets called?

推荐答案

Swift 2.0

使用 userInfo 传递信息，这是一个可选的类型字典[NSObject： AnyObject]？

Pass info using userInfo which is a optional Dictionary of type [NSObject : AnyObject]?

  let imageDataDict:[String: UIImage] = ["image": image]

  // Post a notification
  NSNotificationCenter.defaultCenter().postNotificationName(notificationName, object: nil, userInfo: imageDataDict)

 // Register to receive notification in your class
 NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: notificationName, object: nil)

 // handle notification
 func showSpinningWheel(notification: NSNotification) {
  if let image = notification.userInfo?["image"] as? UIImage {
  // do something with your image   
  }
 }

Swift 3.0版本

userInfo现在需要[AnyHashable：Any]？作为参数，我们在Swift中提供字典文字

The userInfo now takes [AnyHashable:Any]? as an argument, which we provide as a dictionary literal in Swift

  let imageDataDict:[String: UIImage] = ["image": image]

  // post a notification
  NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict) 
  // `default` is now a property, not a method call

 // Register to receive notification in your class
 NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil)

 // handle notification
 func showSpinningWheel(_ notification: NSNotification) {

  if let image = notification.userInfo?["image"] as? UIImage {
  // do something with your image   
  }
 }

注意：通知名称不再是字符串，而是Notification.Name类型，因此我们使用 NSNotification.Name（rawValue：notificationName）我们可以使用自己的自定义通知扩展Notification.Name。

NOTE: Notification "names" are no longer strings, but are of type Notification.Name, hence why we are using NSNotification.Name(rawValue:"notificationName") and we can extend Notification.Name with our own custom notifications.

extension Notification.Name {
static let myNotification = Notification.Name("myNotification")
}

// and post notification like this
NotificationCenter.default.post(name: .myNotification, object: nil)

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