信号量以同步方式运行异步方法 [英] Semaphores to run asynchronous method synchronously

问题描述

在我的应用程序中，我使用了异步类方法，该方法需要同步运行。

In my app, I use an asynchronous class method, that I need to run synchronously.

据我了解，我应该使用信号量来完成此操作。使用信号量是我以前从未做过的事情，所以现在我正在努力将它们放在正确的位置。

As far as I understand, I should use semaphores to accomplish this. Using semaphores is something I never had to do before, so now I'm struggling to put them in the right place.

我希望你们中的一些人可以在这里帮助我。

I hope some of you could help me out here.

这是我的代码：

-(void)CreateNewerEventInCalendar:(Event*)myEvent{
     [MyCalendar requestAccess:^(BOOL granted, NSError *error) {
                if (granted) {
            BOOL result = [MyCalendar addEventAt:myEvent.StartPoint withTitle:myEvent.Subject inLocation:myEvent.Location];
            if (result) {
                // added to calendar
            } else {
                // unable to create event/calendar
            }
        } else {
            // you don't have permissions to access calendars
        }
    }];

}

推荐答案

尝试一下：

dispatch_semaphore_t sema = dispatch_semaphore_create(0);

[MyCalendar requestAccess:^(BOOL granted, NSError *error) {

    // your implementation
    dispatch_semaphore_signal(sema);
}];

dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
// continue here

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