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POMultithread core data merge error
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  1. POMultithread core data merge error
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    copied!<p>The standard way of using multithread core-data is </p> <pre><code>[mainContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:) withObject:notification waitUntilDone:YES]; </code></pre> <p>However, the one have external managed object that save immediately after another. This creates errors. For example:</p> <pre><code>- (void)mergeChanges:(NSNotification *)notification { NSManagedObjectContext *mainContext = [self managedObjectContext]; // Merge changes into the main context on the main thread [mainContext performSelectorOnMainThread:@selector(mergeChangesFromContextDidSaveNotification:) withObject:notification waitUntilDone:YES]; } - (void) loadingIntoCoreData { NSManagedObjectContext *ctx = [[NSManagedObjectContext alloc] init]; [ctx setUndoManager:nil]; [ctx setPersistentStoreCoordinator: [self persistentStoreCoordinator]]; NSNotificationCenter *nc = [NSNotificationCenter defaultCenter]; [nc addObserver:self selector:@selector(mergeChanges:) name:NSManagedObjectContextDidSaveNotification object:ctx]; ... // Create many objects [ctx save:&amp;error]; [self doSomethingWithThisCtx:ctx]; } - (void) doSomethingWithThisCtx:(NSManagedObjectContext *)ctx{ // Form relationships with objects create in - (void) loadingIntoCoreData [ctx save:&amp;error]; } </code></pre> <p>Then on the second [ctx save:&amp;error] will throw an "EXC_BAD_ACCESS" error.</p> <p>How would one insert into core data and create relationships with the new objects on a separate thread? It works fine on the main thread but since it's done during <code>applicationDidLaunched</code>, then the UI get locked up.</p>
 

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