NSNotificationQueue多线程
首先上代码:
- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect]; [button setFrame:CGRectMake(0, 0, 400, 60)]; [button addTarget:self action:@selector(buttonDown) forControlEvents:UIControlEventTouchUpInside]; [button setTitle:@"Post Notification" forState:UIControlStateNormal]; [self.view addSubview:button]; dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(actionNotification:) name:kNotificationName object:nil]; }); } - (void) actionNotification: (NSNotification*)notification { NSString* message = notification.object; NSLog(@"%@",message); sleep(5); NSLog(@"Action Notification Finish"); } - (void)buttonDown { dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ NSNotification *notification = [NSNotification notificationWithName:kNotificationName object:@"object"]; [[NSNotificationQueue defaultQueue] enqueueNotification:notification postingStyle:NSPostASAP]; }); NSLog(@"buttonDown"); }
打印信息如下:
2015-03-17 18:47:20.131 AppTest[19507:206469] buttonDown
也就是说,观察者们和poster有可能都在不同的子线程中,这样观察者们就收不到通知事件,
这里有个解决方法是把通知队列放主线程中去;
还有个解决方法就是把NSPostASAP改为NSPostNow。
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