iphone - Get notification when NSOperationQueue finishes all tasks -

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NSOperationQueue is wait other operators , but I do not want to wait Synchronous for this. I want to hide the progress indicator in UI when qi is over.

What is the best way to accomplish this?

I can not send notifications from my NSOperation , because I do not know who will be the last, and [queue operation] is not yet empty (Or worse - repipulated) when the notification is received.

> Use KVO to inspect your queue property, then you can tell what your queue is [queue] collaboration count] == ​​0 Was completed by checking for.

In the file you are doing KVO from anywhere, announce a reference for this type ():

Fixed NSString * kQueueOperationsChanged = @ "kQueueOperationsChanged";

When you organize your queue, do this: 

  [self.queue addObserver: Path to self: @ "Operation" option: 0 Reference: & amp; KQueueOperationsChanged];

Then enter your in ValleForKeyPath : 

  - (zero) Inspection valueforcover: (NSString *) The keypad object: (Id) object change: (nsDictionary *) reference references: (zeros *) reference {if (object == self key & amp; keypath, excelstostring: @ "operation"] and complex == & Amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; amp; ############ @ "Queue has completed"); }} And {[Super Avonwolf Four Path: Object of the Keypath: Object Changes: Change Reference: Context]; }}

(It is believed that your NSOperationQueue is in the property queue )

something But before your object completely deluxe (or when this queue stops caring for the state), you have to cancel the registration with KVO in this way: 

  [self.queue removeObserver : Self forKeyPath: @ "Operations" Reference: & amp; Amp; Qiuopathy changed]; Appendix: iOS 4.0 has a  NSOperationQueue.operationCount  property, which corresponds to KVO according to the documents. This answer will still work in iOS 4.0, so it is still useful for previous compatibility.

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