NSNotification Center:-
An NSNotificationCenter object (or simply, notification center) provides a mechanism for broadcasting information within a program. An NSNotificationCenter object is essentially a notification dispatch table.
OBJECTS register with a notification center to receive notifications (NSNotification objects) using the addObserver:selector:name:object: or addObserverForName:object:queue:usingBlock: methods. Each invocation of this method specifies a set of notifications. Therefore, objects may register as observers of different notification sets by calling these methods several times.
Each running Cocoa program has a default notification center. You typically don’t create your own. An NSNotificationCenter object can deliver notifications only within a single program. If you want to post a notification to other processes or receive notifications from other processes, use an instance of NSDistributedNotificationCenter.
Initially create the file name (b8 notification view controller)
b8 notification view controller .h:
# import #import “second .h” @interface b8 notification view controller: UIviewController { } @end
b8 notification view controller .m:
-(void)viewDid load { [[NSNotificationCenter defaultCenter] add observe : selfSelector:@ selector :@ selector (addition) name :@ “ AlgebraNotification” Object : nil]; [[NSNotificationCenter defaultCenter ] addobserver : self Selector :@ selector (subtraction) name :@ “algebra notification” Object : nil]; [[NSNotificationCenter defaultCenter PostNotificationName: @ “AlgebraNotification” Object: nil]; [ Super viewDidLoad]; } -(void) addition { NSLog(@ “ the addition is called”) } -(void) Subtraction { Ns log(@ “the subtraction is called); }
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Output:– the addition is called
The subtraction is called
program for the notification center to create an another class
NSNotificationSecondViewController. h:-
# import # import “math .h” @ interface NSNotificationSecondViewController :UIViewController { } @end
NSNotificationSecondViewController .m:-
# import “NSNotificationSecondviewController .h” @ implementation NSNotificationSecondviewController -(void) view Did load {
[[NSNotificationCenter defaultCenter]
Add observer :self Selector : @ selector (addition); Name : @ “algebra notification” Object : nil]; <strong>[[NSNotificationCenter defaultCenter]</strong> add observer : self Selector :@ selector(subtraction) Name : @ “algebra notification” Object : nil];
//Create an object to math class:
Math *mathobj =[[math alloc]init]; [[NSNotification center default center] Add observer : mathobj Selector : @ selector (multiplication); Name : @ “algebra notification); Object : nil ];
// post notification math class method:
[Math obj postNotificationMathclass] [Super view did load]; } -(void) addition : (NSNotification *) aNotification { NSDictionary * aDict = [a Notification userInfo]; NSLog (@ “addition is called %@”, aDict ]; } -(void) subtraction :( NSNotification *) aNotification { Ns dictionary *a dict = [ a notification user info}; NSLog (@ “ subtraction is called % @”, aDict); } à//by orating the class for math Class àaddànew fileàcocaa touch class Objective-c class Next click File name :math .m Math. h [automatically create . h] fini
Math. h:-
# import @interface Math : NSobject { } -(void) PostNotificationMathClass; @end
Math .m:-
#import “Math .h” @implementation Math - (void) PostNotificationMathClass { NSDictionary * aDict = [NSDictionary dictionarywithObjectsAndkeys: @ “ vamshi”, @ “divya”, nil]; [[NSNotificationCenter defaultCenter] PostNotificatioName:@ “AlgebraNotification” Object : nil User info : aDict]; } -(void) multiplication { NSLog (@ “multiplication is called”); } @end
Output:– addition is called {
Divya = vamshi;
}
Subtraction is called
{
Divya = vamshi;
}
Multiplication is called.
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