Igor Delovski Board

[Ike]

Marcus Zarra - Cocoa Tutorial: NSOperation and NSOperationQueue

"Fortunately, Apple has made a lot of progress in OS X 10.5 Leopard. NSThr-
ead itself has received a number of very useful new methods that make thr-
eading easier. In addition, they have introduced two new objects: NSOpera-
tion and NSOperationQueue. In this Tutorial I will walk through a basic exam-
ple that shows how to use these new Objects and how they make multi-thr-
eading your application nearly trivial."

[Ike]

SO - iPhone - return from an NSOperation

"I am using a subclass of NSOperation to do some background processes.
I want the operation to be cancelled when the user clicks a button. To can-
cel an operation (on a button click for instance), I tried calling -cancel but it
doesn't make a difference. Also tried calling -finish but even that doesn't
change anything."

[delovski]

iPhone - Posix Threads for the win

"I found that using Posix threads were slightly (1-2%) faster than NSThre-
ads. Currently, I've set my engine up to have 2 additional threads. One to
handle the game updating and rendering, and a second to handling job lo-
ading, with jobs being streaming in audio and textures. To handle synchro-
nisation I'm using spin locks, which are basically while loops."

[delovski]

iCodeBlog - Turbo Charging Your Apps With NSOperation

"Today, I will show you the simplest one: NSInvocationOperation. NSInvo-
cationOperation is a subclass of NSOperation which allows you to specify a
target and selector that will run as an operation."

[delovski]

discussions.apple.com - UIActivityIndicatorView in IBAction function

"I was wrong - you have to get back to the run loop for it to animate.

However you can do this pretty easily performing your long operation with
NSOperationQueue. Here's a simple example..."

[delovski]

MF - Offscreen bitmap drawing from background thread

"I have a scrollview containing about 100 smaller views, all the same size as
the screen. My problem is that when my app wants to show the scrollview it
takes about 5 seconds to create the contents of all those smaller views which
makes the app freeze for 5 seconds."

[delovski]

Jeff LaMarche - PSA: Respect the Main Thread

"Usually, I see these sleepForTimeInterval: calls in applications that do
some kind of asynchronous network communication. My guess is that the
developers who wrote these applications came from Java, .Net, or some
other language where network communication is commonly handled on a
non-main thread."

[delovski]

Jeff LaMarche - Downloading Images for a Table without Threads

"I've written a small iPhone app that downloads images from Deviant Art.
You just enter somebody's Deviant Art username into a text field and the
application will grab the the images in that person's gallery, download them
asynchronously, and display each one in the table once it's finished down-
loading."

[delovski]

MF - Inter Thread Communication

"I want to be able to output the timer to a label back on my view controller
that is going to queue the NSOperation subclass.

I've found 'performSelectorOnMainThread:' method which should do what I
need. However, I'm a little fuzzy on how I can reference the main thread in
that function."

[delovski]

iphonedevsdk.com - NSThread-ing and SQLITE calls

"As it sends in "performselectorinMainThread" I'm looking for a way to make
sure that the method is independent of such calls, and thats why i've been
trying the performSelectorInBackgroundThread.. and NSThread detach..."

[delovski]

cimgf, Matt Long - NSOperation Example

"While looking around the Internet, I noticed that the only examples of using
NSOperation available were related to scientific applications. I wanted some-
thing that I could relate to a little better and since I’ve been working with QT-
Kit a lot lately, I figured it would be a good framework to build from."

[delovski]

so - Multi-Threading question in Objective-C 2.0

"I have my main application delegate which contains a method that returns
an object. This application delegate runs on the main thread.

I also have a NSOperation that gets run on a different thread. As well as
wanting to be able to call my app delegate method on my main thread
sometimes, I also need to call it from my NSOperation thread to get the
object that it returns."

[delovski]

cocoa samurai - A Guide to Threading on Leopard

"It's becoming abundantly clear that one big way you can increase appli-
cation performance is multithreading, this is because increasing processor
speeds are no longer a viable route for increasing application performance,
although it does help. Multithreading is splitting up your application into
multiple threads that execute concurrently with some threads having ac-
cess to the same data structures that your main thread has access to."

[delovski]

so - Queue of NSOperations and handling application exit

"How do I handle the situation where the application exits? As the operations
run in detached threads, how can I make the main thread wait until the cur-
rent operation is "safe" to quit?"

[delovski]

adc - Mac OS X manual page for Atomic

"atomic add, increment, decrement, or, and, xor, compare and swap,
test and set, test and clear, spinlocks, and lockless queues"

[delovski]

so - NSOperation on the iPhone

"The ideal solution here would be to describe a use-case scenario for
NSOperation and how you would use it to solve your problem(s)."

[Ike]

so - iOS App Architecture with NSOperations

"Does it create too much overhead? Does it even make sense? How you,
personally, implement concurrent operations?"

[Ike]

MF - NSThread-ing and SQLITE calls

"In the operation it accesses the database and gets the results in chunks. I
found that 300 rows per chunk was a good size, YMMV. After each chunk has
been accumulated into an array that array is send to the main thread using
performMethodOnMainThread. The main thread then adds the results from
the array to its data model and calls reloadData."

[delovski]

nshipster - NSOperation

"Examples of tasks that lend themselves well to NSOperation include network
requests, image resizing, text processing, or any other repeatable, structured,
long-running task that produces associated state or data.

But simply wrapping computation into an object doesn't do much without a
little oversight. That's where NSOperationQueue comes in NSOperationQueue"

[delovski]

so - UI API called on a background thread error

"UI API called on a background thread"

[delovski]

medium - Managing background tasks with the new Task Scheduler in iOS 13

"Apple released another great framework this year, and this time it is the
BackgroundTasks framework. We can use it to schedule and control the
execution conditions of our background jobs. BackgroundTasks framework
allows us to plan and run background work according to required criteria like
when the battery is charging, connection availability, etc. BackgroundTasks
framework has various task types."

[delovski]

ioscoachfrank.com - Everything You Know About GCD Is a Lie

"Turns out that dispatching to the global queue is awful for performance.

Since the global queue lives right above the thread pool, it has to take liberties
with regards to how it handles quality of service and priorities. This means that
GCD (or more specifically, its scheduler) has less to work with when scheduling
your work."