user102008 user102008 - 6 months ago 34
Objective-C Question

How to use performSelector:withObject:afterDelay: with primitive types in Cocoa?

The

NSObject
method
performSelector:withObject:afterDelay:
allows me to invoke a method on the object with an object argument after a certain time. It cannot be used for methods with a non-object argument (e.g. ints, floats, structs, non-object pointers, etc.).

What is the simplest way to achieve the same thing with a method with a non-object argument? I know that for regular
performSelector:withObject:
, the solution is to use
NSInvocation
(which by the way is really complicated). But I don't know how to handle the "delay" part.

Thanks,

Answer

Here is what I used to call something I couldn't change using NSInvocation:

SEL theSelector = NSSelectorFromString(@"setOrientation:animated:");
NSInvocation *anInvocation = [NSInvocation
            invocationWithMethodSignature:
            [MPMoviePlayerController instanceMethodSignatureForSelector:theSelector]];

[anInvocation setSelector:theSelector];
[anInvocation setTarget:theMovie];
UIInterfaceOrientation val = UIInterfaceOrientationPortrait;
BOOL anim = NO;
[anInvocation setArgument:&val atIndex:2];
[anInvocation setArgument:&anim atIndex:3];

[anInvocation performSelector:@selector(invoke) withObject:nil afterDelay:1];