如何使用 swift 3.0 中的 NotificationCenter 和 swift 2.0 中的 NSNotificationCenter 传递数据? [英] How to pass data using NotificationCenter in swift 3.0 and NSNotificationCenter in swift 2.0?
问题描述
我正在我的 swift ios 应用中实现 socket.io
.
I'm implementing socket.io
in my swift ios app.
目前在几个面板上,我正在侦听服务器并等待传入消息.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 - 现在我只想开始监听传入的消息一次,当任何消息到来时 - 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,我能够传递发生了某些事情的信息,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)
然后我有一个函数叫做:
then I had a function called:
func showSpinningWheel(notification: NSNotification) {
}
任何时候我都想称之为我正在做的:
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,userInfo
是 [NSObject : AnyObject] 类型的可选字典?
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、4.0、5.0 及以上版本
userInfo 现在采用 [AnyHashable: Any]?作为参数,我们在 Swift 中将其作为字典文字提供
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
// 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")
,我们可以使用我们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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