Folk dancing bubble sort

I am always fond of any visualization of algorithms and making (not so) complex things easy to understand for everyone.

NSInvocation in Objective C via delegate

I had some hard time finding the solution for a smooth usage of NSInvocation.
Furthermore I was to call a method within a delegate.

All's well that ends well and I am happy now.

Here is my code snippet.
My very last error was that I forgot to call the setSelector method :)

if (self.delegate)
{
  SEL sel = @selector(fetchComplete:withParam1:withParam3:);
  if (self.delegate!=nil && [self.delegate respondsToSelector:sel])
  {
      NSMethodSignature *sig = [[self.delegate class] instanceMethodSignatureForSelector:sel];
      NSInvocation *inv = [NSInvocation invocationWithMethodSignature:sig];
    
      [inv setSelector:sel];
      [inv setTarget:self.delegate];
      [inv setArgument:&Param1 atIndex:2];
      [inv setArgument:&Param2 atIndex:3];
      [inv setArgument:&Param3 atIndex:4];
    
      [inv invoke];
    
//            [self.delegate performSelector:@selector(fetchComplete:withParam1:withParam2:)
//                                withObject:elementtype
//                                withObject:Param2
//                                withObject:Param3
//                                ];
  }
}