NSNotification相关

addObserver:selector:name:object:

Adds an entry to the receiver’s dispatch table with an observer, a notification selector and optional criteria: notification name and sender.

- (void)addObserver:(id)notificationObserver selector:(SEL)notificationSelector name:(NSString *)notificationNameobject:(id)notificationSender

Parameters

notificationObserver

Object registering as an observer. This value must not be nil.

指定观察者是谁，此参数不能为空，一般为self

notificationSelector

Selector that specifies the message the receiver sends notificationObserver to notify it of the notification posting. The method specified by notificationSelector must have one and only one argument (an instance of NSNotification).

观察者要响应的方法，此方法必须要有而且只有一个参数'NSNotification'

notificationName

The name of the notification for which to register the observer; that is, only notifications with this name are delivered to the observer.

If you pass nil, the notification center doesn’t use a notification’s name to decide whether to deliver it to the observer.

通知的名称，在通知中心注册的名字

notificationSender

The object whose notifications the observer wants to receive; that is, only notifications sent by this sender are delivered to the observer.

If you pass nil, the notification center doesn’t use a notification’s sender to decide whether to deliver it to the observer.

谁发送的这个通知

postNotificationName:object:userInfo:

Creates a notification with a given name, sender, and information and posts it to the receiver.

- (void)postNotificationName:(NSString *)notificationName object:(id)notificationSender userInfo:(NSDictionary*)userInfo

Parameters

notificationName

The name of the notification.

notificationSender

The object posting the notification.

userInfo

Information about the the notification. May be nil.

   通知中心的内容

//点击按钮

- (IBAction)btnPressed:(id)sender

{

    [[NSNotificationCenterdefaultCenter] postNotificationName:@"hello"object:niluserInfo:[NSDictionarydictionaryWithObject:@"YES"forKey:@"result"]];

}

//注册通知

[[NSNotificationCenterdefaultCenter] addObserver:selfselector:@selector(hello:)name:@"hello"object:nil];

//响应通知

- (void)hello:(NSNotification *)sender

{

   NSDictionary *dict = [sender userInfo];

   NSString *str = [dict objectForKey:@"result"];

   NSLog(@"str = %@",str);

}

//NSNotification的使用

@interface NSNotification :NSObject <NSCopying,NSCoding>

- (NSString *)name;

- (id)object;

- (NSDictionary *)userInfo;

@end