Use of OBJECTIVE-C observer patterns--KVO and Nsnotificationcenter

The principle of KVO and Nsnotificationcenter in Objective-c is a good implementation of the observation pattern, the following code illustrates the usage

The use of KVO

1- (void) Viewdidload {2 [Super Viewdidload];3     //additional setup after loading the view, typically from a nib.4 5Self.model = [modelNew];6     7     //Add Kvo8 [Self.model addobserver:self9Forkeypath:@"name"Ten options:nskeyvalueobservingoptionnew One Context:nil]; A      -     //send information by modifying the properties -Self.model.name =@"v1.0"; the       - } -  - #pragmaMark-kvo method +- (void) Observevalueforkeypath: (NSString *) KeyPath Ofobject: (ID)ObjectChange: (Nsdictionary<nskeyvaluechangekey,ID> *) Change context: (void*) Context { -NSLog (@"%@", change); + } A  at- (void) Dealloc { -  -     //Remove Kvo - [Self.model removeobserver:self -Forkeypath:@"name"]; -}

The use of Nsnotificationcenter

1- (void) Viewdidload {2 [Super Viewdidload];3     //additional setup after loading the view, typically from a nib.4     5     //Add6 [[Nsnotificationcenter Defaultcenter] addobserver:self7 selector: @selector (notificationcenterevent:)8Name@" Science"9                                                Object: nil];Ten      One     //Send Message A[[Nsnotificationcenter Defaultcenter] Postnotificationname:@" Science" -                                                         Object:@"v1.0"]; -      the } -  - #pragmaMark-Notification Hubs method -- (void) Notificationcenterevent: (ID) Sender { +NSLog (@"%@", sender); - } +  A- (void) Dealloc { at     //Remove notification hubs - [[Nsnotificationcenter Defaultcenter] removeobserver:self -Forkeypath:@" Science"]; -  -}

Use of OBJECTIVE-C observer patterns--KVO and Nsnotificationcenter