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2014/10/15 ¤U¤È 10:07:03
iphone Programming Glossary: dispatch_syncObjective-C, cancel a dispatch queue using UI event http://stackoverflow.com/questions/10066897/objective-c-cancel-a-dispatch-queue-using-ui-event the UI responsive I used dispatch_queue dispatch_async dispatch_get_global_queue DISPATCH_QUEUE_PRIORITY_DEFAULT 0 ^ dispatch_sync dispatch_get_main_queue ^ Show the alert view Start the process of address book modification using dispatch_async modifyingAddressBookQueue.. _fixedNumbers _fixedNumbers 1 dispatch_async dispatch_get_global_queue DISPATCH_QUEUE_PRIORITY_DEFAULT 0 ^ dispatch_sync dispatch_get_main_queue ^ self setAlertViewProgress i cancelledPtr cancelled Code for alertview my own lib delegate..
http://stackoverflow.com/questions/11486828/table-view-scrolling-async 0ul dispatch_async queue ^ UIImage image UIImage imageWithContentsOfFile beer.imagePath beer.image image dispatch_sync dispatch_get_main_queue ^ UITableViewCell cell self.tableView cellForRowAtIndexPath indexPath cell.beerImage.image image..
NSManagedObjectContext performBlockAndWait: doesn't execute on background thread? http://stackoverflow.com/questions/11831946/nsmanagedobjectcontext-performblockandwait-doesnt-execute-on-background-thread However that is not what happens as it would be impossible... for the same reason a deadlock ensues with nested dispatch_sync calls. Just something to be aware of if using the synchronous version. In general avoid sync versions whenever possible.. something to be aware of if using the synchronous version. In general avoid sync versions whenever possible because dispatch_sync can cause a deadlock and any re entrant version like performBlockAndWait will have to make some bad decision to support..
UIStringDrawing methods don't seem to be thread safe in iOS 6 http://stackoverflow.com/questions/12744558/uistringdrawing-methods-dont-seem-to-be-thread-safe-in-ios-6 I have implemented what I thought was a fix by serialising any draw calls using CGD void serialiseDrawing void ^ block dispatch_sync self.serialDrawingQueue block dispatch_queue_t serialDrawingQueue if _serialDrawingQueue NULL _serialDrawingQueue dispatch_queue_create..
ALAsset Photo Library Image Performance Improvements When Its Loading Slow http://stackoverflow.com/questions/13508535/alasset-photo-library-image-performance-improvements-when-its-loading-slow will execute in separate thread . So I suggest to do the UI related stuffs in main thread . To do this either use dispatch_sync dispatch_get_main_queue or performSelectorOnMainThread Some Important Notes Use AlAsset aspectRatioThumbnail instead of.. ALAssetsLibraryAssetForURLResultBlock resultblock ^ ALAsset myasset CGImageRef iref myasset aspectRatioThumbnail dispatch_sync dispatch_get_main_queue ^ itemToAdd UIImageView alloc initWithFrame CGRectMake arrayIndex intValue 320 0 320 320 itemToAdd.image..
How to get user details using twitter api v1.1 (Twitter error 215) http://stackoverflow.com/questions/17081012/how-to-get-user-details-using-twitter-api-v1-1-twitter-error-215 @ user objectForKey @ screen_name NSLog @ pic @ item objectForKey @ user objectForKey @ profile_image_url_https dispatch_sync GCDMainThread ^ @autoreleasepool UIAlertView av UIAlertView alloc initWithTitle @ Complete message @ Your list of followers..
Grand Central Dispatch (GCD) with CoreData http://stackoverflow.com/questions/4264540/grand-central-dispatch-gcd-with-coredata the main thread. As you mention it is when you save the UI update takes place. You can solve this by nesting a call to dispatch_sync on the main thread. dispatch_queue_t main_queue dispatch_get_main_queue dispatch_queue_t request_queue dispatch_queue_create.. objectAtIndexPath NSIndexPath indexPathForRow 0 inSection 0 update and heavy lifting... dispatch_sync main_queue ^ blockSelf saveManagedObjectContext The use of blockSelf is to avoid creating accidentally reference cycles...
How to make ui responsive all the time and do background updating? http://stackoverflow.com/questions/5133731/how-to-make-ui-responsive-all-the-time-and-do-background-updating index Thumbnail thumbnail thumbnails objectAtIndex index thumbnail.image UIImage imageWithContentsOfFile thumbnail.url dispatch_sync mainQueue ^ update UIScrollView using thumbnail. It is safe because this block is on main thread. dispatch_apply waits..
Grand Central Dispatch (GCD) vs. performSelector - need a better explanation http://stackoverflow.com/questions/5225130/grand-central-dispatch-gcd-vs-performselector-need-a-better-explanation waitUntilDone is an Obj C wrapper to the GCD C syntax. I've been thinking of these two commands as equivalent dispatch_sync dispatch_get_main_queue ^ self doit YES self performSelectorOnMainThread @selector doit withObject YES waitUntilDone YES..
Can you use cancel/isCancelled with GCD/dispatch_async? http://stackoverflow.com/questions/5449469/can-you-use-cancel-iscancelled-with-gcd-dispatch-async know NOW or else it will sit there for about 4 to 6 seconds on 4.3 4.2 doing nothing until it realises you are done dispatch_sync dispatch_get_main_queue ^ self attentionBGIsAllDone would setneedsdisplay etc return void buildGuts we are actually in.. CHECKER self blah blah CHECKER self blah blah to get stuff done from time to time on the UI something like... CHECKER dispatch_sync dispatch_get_main_queue ^ supportStuff pleasePostMidwayImage UIImage imageWithCGImage halfOfShip CHECKER self blah blah..
GCD, Threads, Program Flow and UI Updating http://stackoverflow.com/questions/7290931/gcd-threads-program-flow-and-ui-updating but similar issue and can't get UI updated. dispatch_queue_t queue dispatch_queue_create com.gamesbychris.createTree 0 dispatch_sync queue ^ self createTreeFromNode rootNode Need to wait here until createTreeFromNode is finished. solveButton.enabled YES..
Objective-C: Asynchronously populate UITableView - how to do this? http://stackoverflow.com/questions/7491517/objective-c-asynchronously-populate-uitableview-how-to-do-this the new data Note We MIGHT be on a background thread here. if NSThread isMainThread self tableView reloadData else dispatch_sync dispatch_get_main_queue ^ self tableView reloadData And done. A few more lines of code for you to write but it replaces..
loading images from a background thread using blocks http://stackoverflow.com/questions/7502073/loading-images-from-a-background-thread-using-blocks 0 ^ void NSData data0 NSData dataWithContentsOfURL someURL UIImage image UIImage imageWithData data0 dispatch_sync dispatch_get_main_queue ^ void UIImageView imageView UIImageView cell viewWithTag 100 imageView.image image share improve..
http://stackoverflow.com/questions/8878358/obj-c-block-variables share improve this question First str will get updated only after the block is executed. So unless you are using dispatch_sync for that block otherwise at this line str getCharAtIndex 1 the block is unlikely to be executed and str will not get updated...
Why does Apple recommend to use dispatch_once for implementing the singleton pattern under ARC? http://stackoverflow.com/questions/9119042/why-does-apple-recommend-to-use-dispatch-once-for-implementing-the-singleton-pat this question dispatch_once is absolutely synchronous. Not all GCD methods do things asynchronously case in point dispatch_sync is synchronous . The use of dispatch_once replaces the following idiom MyClass sharedInstance static MyClass sharedInstance..
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