如何在 Objective-C 中创建 NSNotification 对象？

我想创建一个 NSNotification 对象，如下所示：

NSNotification *obj=[[NSNotification alloc]init];

但是当我像这样创建时，我收到一个异常“NSConcreteNotification init：不允许”。 我应该如何解决这个问题？

来自NS通知 http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Classes/NSNotification_Class/Reference/Reference.html文档：

您可以使用类方法创建通知对象notificationWithName:object: http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Classes/NSNotification_Class/Reference/Reference.html#//apple_ref/occ/clm/NSNotification/notificationWithName:object: or notificationWithName:object:userInfo: http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Classes/NSNotification_Class/Reference/Reference.html#//apple_ref/occ/clm/NSNotification/notificationWithName:object:userInfo:。但是，您通常不会直接创建自己的通知。 NSNotificationCenter 方法postNotificationName:object: http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Classes/NSNotificationCenter_Class/Reference/Reference.html#//apple_ref/occ/instm/NSNotificationCenter/postNotificationName:object: and postNotificationName:object:userInfo: http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Classes/NSNotificationCenter_Class/Reference/Reference.html#//apple_ref/occ/instm/NSNotificationCenter/postNotificationName:object:userInfo:让您无需先创建通知即可方便地发布通知。