Creating a method to perform animations and wait for completion using a semaphore in objective c

Question

I am trying to create a method which makes use of UIView\'s \"+animateWithDuration:animations:completion\" method to perform animations, and wait for completion. I am well a

Answer 1

As many people pointed out here, is true that the animation runs on the main thread and the semaphore usage stops the main thread. But this still can be done with a semaphore using this approach:

// create semaphore
dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

[UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{

    // do animations

} completion:^(BOOL finished) {

     // send signal
    dispatch_semaphore_signal(semaphore);

}];

// create background execution to avoid blocking the main thread
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

    // wait for the semaphore    
    dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);

    // now create a main thread execution
    dispatch_async(dispatch_get_main_queue(), ^{

        // continue main thread logic

    });

 });