#grand-central-dispatch

Fixed NSOperation vs Grand Central Dispatch #dev #it #asnwer

NSOperation vs Grand Central Dispatch

I’m learning about concurrent programming for iOS. So far I’ve read about NSOperation/NSOperationQueue and GCD. What are the reasons for using NSOperationQueue over GCD and vice versa?

Sounds like both GCD and NSOperationQueue abstract away the explicit creation of NSThreadsfrom the user. However the relationship between the two approaches isn’t clear to me…

Fixed Create singleton using GCD's dispatch_once in Objective C #dev #it #asnwer

Create singleton using GCD’s dispatch_once in Objective C

If you can target iOS 4.0 or above

Using GCD, is it the best way to create singleton in Objective C (thread safe)?

+ (instancetype)sharedInstance { static dispatch_once_t once; static id sharedInstance; dispatch_once(&once, ^{ sharedInstance = [[self alloc] init]; }); return sharedInstance; }

Answer: Create singleton using GCD’s…

Fixed How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:? #dev #it #asnwer

How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?

Is there a way to call a block with a primitive parameter after a delay, like using performSelector:withObject:afterDelay: but with an argument like int/double/float?

Answer: How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?

How about something like this:

dispatch_async(…

How to: NSOperation vs Grand Central Dispatch

NSOperation vs Grand Central Dispatch

I’m learning about concurrent programming for iOS. So far I’ve read about NSOperation/NSOperationQueue and GCD. What are the reasons for using NSOperationQueue over GCD and vice versa?

Sounds like both GCD and NSOperationQueue abstract away the explicit creation of NSThreadsfrom the user. However the relationship between the two approaches isn’t clear to me…

How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?

Is there a way to call a block with a primitive parameter after a delay, like using performSelector:withObject:afterDelay: but with an argument like int/double/float?

Answer: How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?

How about something like this:

dispatch_async(…