Question

I would like to have an NSTimer which executes every 1 second and have another NSTimer which executes within that timer slightly less than 1 second.

Actually I am not sure what is the best way to do this, but I would like a random image to appear every second and then disappear after after that second.

So I need some kind of stall or something which can pass the time and then execute the hide button again.

If I set the buttons hidden to TRUE and then set it to FALSE, this appearance time will be so short, how can I stall or make the second pass and then hide the image again?

Thanks in advance

Answer 1

You can try setting yourself into a constant cycle of showing and hiding the object after a specified interval until you interrupt it by using the performSelector:withObject:afterDelay: method reciprocally in two counter-acting methods:

//On initialization, make a first call to the hide method
//to be executed after a delay
-(void) viewDidload {
    [myObject setHidden:NO];
    [self performSelector:@selector(hideObject) withObject:nil afterDelay:1.0];
}

//Whenever the hide gets called, hide, then make a call to the show method
//to be executed after a delay
-(void) hideObject {
    [myObject setHidden:YES];
    [self performSelector:@selector(showObject) withObject:nil afterDelay:1.0];
}

//Whenever the show gets called, show, then make a call to the hide method
//to be executed after a delay
-(void) showObject {
    [myObject setHidden:NO];
    [self performSelector:@selector(showObject) withObject:nil afterDelay:1.0];
}

You can interrupt the cycle by putting an if statement which checks some end condition for you around the performSelector:withObject:afterDelay: call .