I'm implementing socket.io
in my swift ios app.
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
})
}
}
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.
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)
then I had a function called:
func showSpinningWheel(notification: NSNotification) {
}
and any time I wanted to call it I was doing:
NSNotificationCenter.defaultCenter().postNotificationName(hideSpinner, object: self)
So how can I pass the object messageInfo
and include it in the function that gets called?
This question is related to
ios
swift
swift3
nsnotificationcenter
nsnotifications
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
}
}
}
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
}
}
}
In swift 4.2 I used following code to show and hide code using NSNotification
@objc func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo? [UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
let keyboardheight = keyboardSize.height
print(keyboardheight)
}
}
Hello @sahil I update your answer for swift 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
}
}
}
Hope it's helpful. Thanks
this is how I implement it .
let dictionary = self.convertStringToDictionary(responceString)
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "SOCKET_UPDATE"), object: dictionary)
Source: Stackoverflow.com