CODEWITHSUNDEEP
objective-cmethodsselectornsoperationnsoperationqueue
zhuber
zhuber

Reputation: 5534

NSOperationQueue finished wont start new method

When my observer tells me that there are no more operations, function is not called (performSelector...). Funny thing is that NSLog(@"queue has completed") is logged correctly.

- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object
                     change:(NSDictionary *)change context:(void *)context
{
if (object == self.operationQueue && [keyPath isEqualToString:@"operations"]) {
    if ([self.operationQueue.operations count] == 0)
    {
        [self performSelector:@selector(refreshCollectionView) withObject:nil afterDelay:0.2];
        // Do something here when your queue has completed
        NSLog(@"queue has completed");

    }
}
else {
    [super observeValueForKeyPath:keyPath ofObject:object
                           change:change context:context];
}
}

EDIT

Got it:

dispatch_async(dispatch_get_main_queue(), ^{
             [self performSelector:@selector(refreshCollectionView) withObject:nil afterDelay:0.2];
             });

Dunno why performSelectorOnMainThread... didnt work but it works this way.

Upvotes: 1

Views: 64

Answers (1)

bbum
bbum

Reputation: 162722

If your observer is being fired on the same thread as the queue, it is quite likely that the queue's thread is being reaped upon completion. Since -performSelector:...afterDelay: requires a running run loop, it is likely dropped on the floor.

Since you are updating the UI anyway, perform that selector on the main thread.

Upvotes: 1

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