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Objective-CのNSNotificationCenterを介してメッセージを送受信しますか？

Objective-CのNSNotificationCenterを使ってメッセージを送受信しようとしています。しかし、私はこれを行う方法に関する例を見つけることができませんでした。 NSNotificationCenterを介してどのようにメッセージを送受信しますか？

iosobjective-cnsnotificationcenter
587
Cathy
@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:) 
        name:@"TestNotification"
        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"])
        NSLog (@"Successfully received the test notification!");
}

@end

...他のクラスのどこかに...

- (void) someMethod
{

    // All instances of TestClass will be notified
    [[NSNotificationCenter defaultCenter] 
        postNotificationName:@"TestNotification" 
        object:self];

}
991
dreamlax

dreamlaxの例を拡張するには ...通知とともにデータを送信する場合

転記コード

NSDictionary *userInfo = 
[NSDictionary dictionaryWithObject:myObject forKey:@"someKey"];
[[NSNotificationCenter defaultCenter] postNotificationName: 
                       @"TestNotification" object:nil userInfo:userInfo];

コードを観察する場合：

- (void) receiveTestNotification:(NSNotification *) notification {

    NSDictionary *userInfo = notification.userInfo;
    MyObject *myObject = [userInfo objectForKey:@"someKey"];
}
219
Michael Peterson

これは私を助けました：

// Add an observer that will respond to loginComplete
[[NSNotificationCenter defaultCenter] addObserver:self 
                                             selector:@selector(showMainMenu:) 
                                                 name:@"loginComplete" object:nil];


// Post a notification to loginComplete
[[NSNotificationCenter defaultCenter] postNotificationName:@"loginComplete" object:nil];


// the function specified in the same class where we defined the addObserver
- (void)showMainMenu:(NSNotification *)note {
    NSLog(@"Received Notification - Someone seems to have logged in"); 
}

出所： http://www.smipple.net/snippet/Sounden/Simple%20NSNotificationCenter%20example

47
j7nn7k

ブロックを使用する可能性もあります。

NSOperationQueue *mainQueue = [NSOperationQueue mainQueue];
[[NSNotificationCenter defaultCenter] 
     addObserverForName:@"notificationName" 
     object:nil
     queue:mainQueue
     usingBlock:^(NSNotification *notification)
     {
          NSLog(@"Notification received!");
          NSDictionary *userInfo = notification.userInfo;

          // ...
     }];

アップルのドキュメント

47
Xavi Gil

ビューの更新にNSNotificationCenterを使用している場合は、dispatch_asyncを呼び出してメインスレッドから送信することを忘れないでください。

dispatch_async(dispatch_get_main_queue(),^{
    [[NSNotificationCenter defaultCenter] postNotificationName:@"my_notification" object:nil];
});
38
eiran