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POrun performSegueWithIdentifier inside a queue
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copied!<p>I'm trying to run a task in a new queue and then when this task is finish to inform to the VC to run a performSegueWithIdentifier to pass the next view controller.</p> <p>In a method button I have this call:</p> <pre><code> - (IBAction)previewButtonTouchedIn:(id)sender { prepareDesign(self.imageToEdit,self.maskImageToPrint,self.drawingView,^(UIImage* imageReturn){ self.previewDesignImage = imageReturn; [self performSegueWithIdentifier:PREVIEW_SEGUE sender:self]; }); } </code></pre> <p>and the method called, contains:</p> <pre><code> void prepareDesign(UIImage *imageToEdit,UIImage *maskImageToPrint,UIView *drawingView, void (^block)(UIImage*) { dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ //Here the task which I want to run in a new queue UIImage *imageSnapShot = [UIImage imageWithCGImage:imageRef]; CGImageRelease(imageRef); //I have tested with dispatch_sync and dispatch_async. dispatch_sync(dispatch_get_main_queue(), ^{ block(imageSnapShot);}); }); } </code></pre> <p>I have tested with </p> <pre><code> [[NSOperationQueue mainQueue] addOperationWithBlock:^{ block(imageSnapShot);}]; </code></pre> <p>instead of </p> <pre><code> dispatch_sync(dispatch_get_main_queue(), ^{ block(imageSnapShot);}); </code></pre> <p>And I have checked with breakpoint that the <code>performSegueWithIdentifier</code> is run with the main thread setting the breakpoint in the <code>performSegueWithIdentifier</code> call and in the <code>prepareForSegue:sender:</code>.</p> <p>The screen is simply frozen. Any ideas?</p>

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