Cocoa design model notification

In the past, notifications were hard to handle and were always avoided. However, after a hard time, I found that it was really a good thing to use. Sort out the usage methods.

1. First, add a notification in viewDidLoad or elsewhere

 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateTable:) name:@"updateTable" object:nil];

Nsicationicationcenter is a singleton mode class and has limited methods to call. You can check the api on your own. Addobserver: The following parameters are your current class or the class for receiving messages. Selector: The method to be executed after receiving the notification. The name is the name of the notification, and the object can be used as a parameter for message transmission.

Ii. Define the method to be executed after the notification is completed

-(Void) updateTable :( NSNotification *) sender {NSLog (@ "Notification successful"); NSDictionary * dictionary = (NSDictionary *) [sender userInfo]; NSArray * array = [[NSArray alloc] initWithArray: [dictionary objectForKey: @ "names"]; NSLog (@ "% @, % @", [array objectAtIndex: 0], [array objectAtIndex: 1]);}

Sender is the parameter passed during notification Publishing.

3. Publish a notification when you need to call a method

 [[NSNotificationCenter defaultCenter] postNotificationName:@"updateTable" object:nil userInfo:dictionary];

Dictionary is a previously defined parameter.

 NSArray *array = [[NSArray alloc] initWithObjects:@"foxbabe",@"philiphu", nil];    NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:array,@"names", nil];