NSNotificationQueue多线程

来源：互联网发布：知乎如何收藏文章编辑：程序博客网时间：2024/04/29 22:31

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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