如何在Web3.0中使用NotificationCenter传递数据，在Web2.0中如何使用NSNotificationCenter传递数据？

Question

我正在我的快速ios应用程序中实现socket.io。

目前，在几个面板上，我正在监听服务器并等待传入的消息。为此，我在每个面板中调用getChatMessage函数：

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

然而，我注意到这是一种错误的方法，我需要改变它--现在我只想开始监听传入的消息一次，当任何消息出现时--将此消息传递给任何听它的面板。

因此，我想通过NSNotificationCenter传递传入的消息。到目前为止，我能够传递发生了什么事情的信息，但没有传递数据本身。我是这样做的：

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

然后我有了一个叫做：

func showSpinningWheel(notification: NSNotification) {
}

每当我想叫它的时候，我都在做：

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

那么，如何传递对象messageInfo并将其包含在调用的函数中呢？

Answer 1

SWIFT2.0

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

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
// For swift 4.0 and above put @objc attribute in front of function Definition  
func showSpinningWheel(_ notification: NSNotification) {
    if let image = notification.userInfo?["image"] as? UIImage {
        // do something with your image   
    }
}

SWIFT3.0，4.0，5.0版本及以上

userInfo现在采用AnyHashable:有吗？作为一个论点，我们在Swift中作为字典文本提供

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
// For swift 4.0 and above put @objc attribute in front of function Definition  
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")并可以使用自己的自定义通知扩展Notification.Name。

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

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

Answer 2

斯威夫特3

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) {
        print(notification.userInfo ?? "")
        if let dict = notification.userInfo as NSDictionary? {
            if let id = dict["image"] as? UIImage{
                // do something with your image
            }
        }
 }

斯威夫特4

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
 @objc func showSpinningWheel(_ notification: NSNotification) {
        print(notification.userInfo ?? "")
        if let dict = notification.userInfo as NSDictionary? {
            if let id = dict["image"] as? UIImage{
                // do something with your image
            }
        }
 }

Answer 3

你好，萨希尔，我更新你的回答，为斯威夫特3

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) {
        print(notification.userInfo ?? "")
        if let dict = notification.userInfo as NSDictionary? {
            if let id = dict["image"] as? UIImage{
                // do something with your image
            }
        }
 }

希望能帮上忙。谢谢