Question

I have working code:
[self performSelector:@selector(doSomething) ];

but when I change this line to:

[self performSelector:@selector(doSomething) withObject:nil afterDelay:1.0];

it reports error – unrecognized selector….

could you tell me what is the problem in?

thank you

Answer 1

If you changed your method to take an object parameter then you need to change the @selector() argument to include the “:”, e.g., @selector( doSomething: )

This works:

- (void) foo
{
    NSLog(@"foo!");
}


- (void)applicationDidFinishLaunching:(NSNotification *)aNotification 
{        
    [self performSelector: @selector(foo) withObject: nil afterDelay: 0.1];
}

So you can pass a selector that takes no param to performSelector:withObject:afterDelay: and I presume it ignores the withObject: param which I wasn’t 100% sure of.