http://stackoverflow.com/questions/2191594/send-and-receive-messages-through-nsnotificationcenter-in-objective-c 给出了很好的示例:objective-c
类TestClass的实现:less
@implementation TestClass - (void) dealloc { // If you don't remove yourself as an observer, the Notification Center // will continue to try and send notification objects to the deallocated // object. [[NSNotificationCenter defaultCenter] removeObserver:self]; [super dealloc]; } - (id) init { self = [super init]; if (!self) return nil; // Add this instance of TestClass as an observer of the TestNotification. // We tell the notification center to inform us of "TestNotification" // notifications using the receiveTestNotification: selector. By // specifying object:nil, we tell the notification center that we are not // interested in who posted the notification. If you provided an actual // object rather than nil, the notification center will only notify you // when the notification was posted by that particular object. [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveTestNotification:) // 响应时调用的函数,由于函数有参数,全部后带冒号 name:@"TestNotification" // 必须是字符串 object:nil]; return self; } - (void) receiveTestNotification:(NSNotification *) notification { // [notification name] should always be @"TestNotification" // unless you use this method for observation of other notifications // as well. if ([[notification name] isEqualToString:@"TestNotification"]) // 这个判断颇有必要,其余notification name也可能执行该函数 NSLog (@"Successfully received the test notification!"); } @end
在另一个类中:ide
- (void) someMethod { // All instances of TestClass will be notified [[NSNotificationCenter defaultCenter] postNotificationName:@"TestNotification" object:self]; }
当调用someMethod方法时,会触发TestClass中的receiveTestNotification方法。函数
若是须要传递数据,须要把receiveTestNotification
修改为:post
- (void) receiveTestNotification:(NSNotification *) notification NSDictionary *userInfo = [notification object]; }
如此触发:this
NSDictionary *userInfo = [NSDictionary dictionaryWithObject:myObject forKey:@"someKey"]; [[NSNotificationCenter defaultCenter] postNotificationName: @"TestNotification" object:userInfo];