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What's difference between NSNotification's object and userInfo?
When I post a notification with a parameter, I can use object or userInfos to do it. But I do not know what the difference is between these two ways.
Is there some advantages to using userInfo? Or is using object enough?
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A structure that defines the name of a notification.
A notification dispatch mechanism that enables the broadcast of information to registered observers.
It uses the Observer pattern to inform registered observers when a notification comes in, using a central dispatcher called NotificationCenter. Before we get started, some quick notes: The NotificationCenter class used to be called NSNotificationCenter – with the “NS” prefix – prior to Swift 3.
addObserver(self, — This is for the class where we are going to observer notification. selector: #selector(loginSuccess) — This is the method name, whenever notification will receive this method call. name: NSNotification.Name(“com.
The object represent the object which posted the notification. userInfo contains the additional information/data for the receiving object/function.
According to NSNotificationCenter Class Reference:
postNotificationName:object:userInfo:Creates a notification with a given name, sender, and information and posts it to the receiver.
Declaration
Swift
func postNotificationName(_ notificationName: String, object notificationSender: AnyObject?, userInfo userInfo: [NSObject : AnyObject]?)Objective-C
- (void)postNotificationName:(NSString *)notificationName object:(id)notificationSender userInfo:(NSDictionary *)userInfoParameters
notificationNameThe name of the notification.
notificationSenderThe object posting the notification.
userInfoInformation about the the notification. May be nil.
Discussion
This method is the preferred method for posting notifications.
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