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    <p>I've just found this question and wasn't happy with any of the answers. In my opinion neither make good use of the tools available, and passing around arbitrary information in arrays and dictionaries generally worries me.</p> <p>So, I went and wrote a small <code>NSObject</code> category that will invoke an arbitrary selector with a variable number of arguments:</p> <p><strong>Category Header</strong></p> <pre><code>@interface NSObject (NxAdditions) -(void)performSelectorInBackground:(SEL)selector withObjects:(id)object, ... NS_REQUIRES_NIL_TERMINATION; @end </code></pre> <p><strong>Category Implementation</strong></p> <pre><code>@implementation NSObject (NxAdditions) -(void)performSelectorInBackground:(SEL)selector withObjects:(id)object, ... { NSMethodSignature *signature = [self methodSignatureForSelector:selector]; // Setup the invocation NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature]; invocation.target = self; invocation.selector = selector; // Associate the arguments va_list objects; va_start(objects, object); unsigned int objectCounter = 2; for (id obj = object; obj != nil; obj = va_arg(objects, id)) { [invocation setArgument:&amp;obj atIndex:objectCounter++]; } va_end(objects); // Make sure to invoke on a background queue NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithInvocation:invocation]; NSOperationQueue *backgroundQueue = [[NSOperationQueue alloc] init]; [backgroundQueue addOperation:operation]; } @end </code></pre> <p><strong>Usage</strong></p> <pre><code>-(void)backgroundMethodWithAString:(NSString *)someString array:(NSArray *)array andDictionary:(NSDictionary *)dict { NSLog(@"String: %@", someString); NSLog(@"Array: %@", array); NSLog(@"Dict: %@", dict); } -(void)someOtherMethod { NSString *str = @"Hello world"; NSArray *arr = @[@(1337), @(42)]; NSDictionary *dict = @{@"site" : @"Stack Overflow", @"url" : [NSURL URLWithString:@"http://stackoverflow.com"]}; [self performSelectorInBackground:@selector(backgroundMethodWithAString:array:andDictionary:) withObjects:str, arr, dict, nil]; } </code></pre>
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    1. USSteve Wilford
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    1. COThis is the most elegant solution to the problem.
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      1. USIvano.Bilenchi
 

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