等到收到NSNotification

Question

我希望有一种方法暂停执行，直到收到通知，然后再继续。然后在收到通知后继续执行。这样做的最佳方法是什么？

Answer 1

你可以使用NSRunLoop

- (BOOL)method {
__block BOOL finish = NO;
[[NSNotificationCenter defaultCenter] addObserverForName:@"myNotification" object:nil queue:nil usingBlock:^(NSNotification *note) {
    finish = YES;
}];

while(!finish) {
    [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.1]];
}

return YES;
}

Answer 2

在Swift 5中等待超时的通知

    var accountUpdateNotification: Notification?
    NotificationCenter.default.addObserver(forName: Notification.Name(rawValue: ACCOUNT_UPDATE_NOTIFICATION),
                                           object: nil, queue: nil) { notification in
        accountUpdateNotification = notification
    }
    
    // Do action that posts notification

    let startTime = Date()
    let endTime = startTime.addingTimeInterval(10)
    while accountUpdateNotification == nil {
        let nextTime = Date().addingTimeInterval(0.1)
        RunLoop.current.run(until: nextTime)
        if nextTime > endTime {
            NSLog("Didn't receive notification in time")
            return
        }
    }