nsblockoperation | 易学教程

Timer in another thread in Objective - C

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问题 I have to define method which should be invoked periodically with some time interval. I need to invoke it in another thread (NOT main thread), because this method is used to get information from external API and sync data in core data. How do I define this method to not block main thread? 回答1: Unless you have a specific need for timers, you can use Grand Central Dispatch. The following snippet will execute a block after 2 seconds, on the default priority concurrent queue (i.e a background

Timer in another thread in Objective - C

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NSURLSession with NSBlockOperation and queues

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问题 I have an app that currently uses NSURLConnection for the vast majority of its networking. I would like to move to NSURLSession because Apple tells me that is the way to go. My app just uses the synchronous version of NSURLConnection by way of the + (NSData *)sendSynchronousRequest:(NSURLRequest *)request returningResponse:(NSURLResponse **)response error:(NSError **)error class method. I do this within a NSBlockOperation running on an NSOperationQueue so I am not needlessly blocking the main

Swift NSBlockOperation() Leak: cannot make NSBlockOperation() weak

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问题 To avoid a memory leak when using NSBlockOperation in Objective-C, we would have to declare the variable as weak to be able to reference the block operation inside the block (to cancel if needed), typically like this: __weak NSBlockOperation *blockOp = [NSBlockOperation blockOperationWithBlock:^{ if (blockOp.cancelled) { ... } }]; But in Swift, when I try declare my NSBlockOpeartion as weak, it is always nil. weak var blockOp = NSBlockOperation() Without the weak reference, all is fine except

Learning NSBlockOperation

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问题 I'm a big fan of blocks, but have not used them for concurrency. After some googling, I pieced together this idea to hide everything I learned in one place. The goal is to execute a block in the background, and when it's finished, execute another block (like UIView animation)... - (NSOperation *)executeBlock:(void (^)(void))block completion:(void (^)(BOOL finished))completion { NSOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:block]; NSOperation *completionOperation =

Learning NSBlockOperation

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I'm a big fan of blocks, but have not used them for concurrency. After some googling, I pieced together this idea to hide everything I learned in one place. The goal is to execute a block in the background, and when it's finished, execute another block (like UIView animation)... - (NSOperation *)executeBlock:(void (^)(void))block completion:(void (^)(BOOL finished))completion { NSOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:block]; NSOperation *completionOperation = [NSBlockOperation blockOperationWithBlock:^{ completion(blockOperation.isFinished); }];

NSBlockOperation or NSOperation with ALAsset Block to display photo-library images using ALAsset URL

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I am asking this question regarding my questions Display photolibrary images in an effectual way iPhone and Highly efficient UITableView "cellForRowIndexPath" method to bind the PhotoLibrary images . So I would like to request that answers are not duplicated to this one without reading the below details :) Let's come to the issue, I have researched detailed about my above mentioned issue, and I have found the document about operation queues from here . So I have created one sample application to display seven photo-library images using operation queues through ALAsset blocks. Here are the

NSBlockOperation or NSOperation with ALAsset Block to display photo-library images using ALAsset URL

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问题 I am asking this question regarding my questions Display photolibrary images in an effectual way iPhone and Highly efficient UITableView "cellForRowIndexPath" method to bind the PhotoLibrary images . So I would like to request that answers are not duplicated to this one without reading the below details :) Let's come to the issue, I have researched detailed about my above mentioned issue, and I have found the document about operation queues from here. So I have created one sample application

How do I create a NSTimer on a background thread?

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I have a task that needs to be performed every 1 second. Currently I have an NSTimer firing repeatedly every 1 sec. How do I have the timer fire in a background thread (non UI-thread)? I could have the NSTimer fire on the main thread then use NSBlockOperation to dispatch a background thread, but I'm wondering if there is a more efficient way of doing this. The timer would need to be installed into a run loop operating on an already-running background thread. That thread would have to continue to run the run loop to have the timer actually fire. And for that background thread to continue being

How do I create a NSTimer on a background thread?

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问题 I have a task that needs to be performed every 1 second. Currently I have an NSTimer firing repeatedly every 1 sec. How do I have the timer fire in a background thread (non UI-thread)? I could have the NSTimer fire on the main thread then use NSBlockOperation to dispatch a background thread, but I\'m wondering if there is a more efficient way of doing this. 回答1: The timer would need to be installed into a run loop operating on an already-running background thread. That thread would have to