Why we should use thread and how to do it with no additional efforts.

Dominik Haska – Research Software Developer in Jeppesen a Boeing Company

9 years of professional programming including 1 year in IOS

Why ◦ Moore law and physics limitations

How ◦ how to use the potentially power of multicore

devices easily and properly

iPhone 1 – 1 CPU 412 MHz

iPhone 5 – 2 CPU 1300 MHz

iPad 1 – 1 CPU 1000 MHz

iPad 4 (retina) – 2 CPU 1400 MHz

all animations: ◦ GPU is a massive multiprocessor unit

◦ Just use the animation block

[UIView animateWithDuration:1.0 animations:^{

firstView.alpha = 0.0;

secondView.alpha = 1.0;

}];

[UIView beginAnimations:@"ToggleViews" context:nil];

[UIView setAnimationDuration:1.0];

// Make the animatable changes.

firstView.alpha = 0.0;

secondView.alpha = 1.0;

// Commit the changes and perform the animation.

[UIView commitAnimations];

Animation block stops user interaction during animation

animateWithDuration:delay: options: animations:completion:

UIViewAnimationOptions: ◦ UIViewAnimationOptionAllowUserInteraction

◦ UIViewAnimationOptionBeginFromCurrentState

[self.layer removeAllAnimations];

CGRect animatedFrame = [self.animatedView.layer.presentationLayer frame];

CGRect targetFrame = self. animatedView.frame;

if(animatedFrame.origin.x != 0.0 || animatedFrame.origin.y != 0.0){ CGFloat xMis = animatedFrame.origin.x –

targetFrame.origin.x; CGFloat yMis = animatedFrame.origin.y - targetFrame.origin.y; [fix the position]; }

Create property with quee

◦ [NSOperationQueue new];

Create invocation

◦ NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self

selector:@selector(calculate) object:nil];

Add operation to quee

◦ [self.renderingQueue addOperation:operation];

Or remove (cancelAllOperations)

Some code have to be executed in main thread ◦ [NSString sizeWithFont] – sometimes – once per 1-2 day crashes app

◦ [[UIView alloc] init] ◦ [view addSubview…]

Solution ◦ Delegate and perform on main thread

performSelectorOnMainThread:@selector(

◦ Use NSAttributedString to work with UIKit Additions ◦ Always check when app crashes in which thread are

you

dispatch_async(dispatch_get_global_qu

eue(DISPATCH_QUEUE_PRIORITY_DEFAULT),

^{

your code here

}

Long time for response

Multiple resources needed in parraler (webbrowsers)

Ready to use in ios:

[SSLConnection

sendAsynchronousRequest:request

queue:[NSOperationQueue mainQueue]

completionHandler:^(NSURLResponse*

response, NSData* data, NSError*

error){ … }

You have multicore devices – use this Look for simplest solution – use library as

much as possible Focus on user interaction – do not freeze your

apps Be carefull with debugging – single thread

app is much more testable – much much more

I work for jeppesen boeing company – if i show you sample code I have to kill you ;) – but next time I try to be better

developer.apple.com

http://www.gotw.ca/publications/concurrency-ddj.htm - the free lunch is over

http://www.robotswillstealyourjob.com/ - robots are stealing your job – and engineers help them to

http://www.extremetech.com/computing/116561-the-death-of-cpu-scaling-from-one-core-to-many-and-why-were-still-stuck/2