objective c - How to pass an argument to a method called in a NSTimer

Question

I have a timer calling a method but this method takes one paramether:

theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval target:self selector:@selector(timer) userInfo:nil repeats:YES];

should be

theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval target:self selector:@selector(timer:game) userInfo:nil repeats:YES];

now this syntax doesn't seems to be right. I tried with NSInvocation but I got some problems:

timerInvocation = [NSInvocation invocationWithMethodSignature:
        [self methodSignatureForSelector:@selector(timer:game)]];

theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval
        invocation:timerInvocation
        repeats:YES];

How should I use Invocation?

Answer 1

Given this definition:

- (void)timerFired:(NSTimer *)timer
{
   ...
}

You then need to use @selector(timerFired:) (that's the method name without any spaces or argument names, but including the colons). The object you want to pass (game ?) is passed via the userInfo: part:

theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval 
                                            target:self 
                                          selector:@selector(timerFired:) 
                                         userInfo:game
                                          repeats:YES];

In your timer method, you can then access this object via the timer object's userInfo method:

- (void)timerFired:(NSTimer *)timer
{
    Game *game = [timer userInfo];
    ...
}