Question

here is an absolute brain destroyer:

NOTE: I am using XCode 4.2 with iOS 5 and ARC (Automatic Reference Counting)

If anybody can help explain why none of my variables are retaining their value I will be grateful beyond reason. Currently I have this int variable speed. Heres the basic code rundown:

In Header File:

@interface GameLoop : NSObject {
   CADisplayLink *refresh;

   int speed;
}

In .m File:

- (void)awakeFromNib {
   screenRefresh = [CADisplayLink displayLinkWithTarget:self selector:@selector(updateGame:)];
   [screenRefresh setFrameInterval:1];
   [screenRefresh addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode]; 
}

- (void)createNewGame {
   speed = 4;
}

- (void)updateGame:(CADisplayLink *)gameTime {
   [factory slideViews:speed];  // <---- Speed ALWAYS equals 0
}

The factory class simply moves stuff around. If I plug in 4 in place of speed everything works perfectly. I have also tried making speed by:

@property (nonatomic, assign) int speed;

And synthesising and using self.speed. If anyone can help, I would be very thankful! I’m sure it’s something simple, but just the fact that I assign in one method and it doesn’t follow through in another drives me insane. I also have used NSLog("%d", speed) and it spits out the correct value in the method I assign it in, and when I re-call it before assigning.

Update
After a little debugging, it appears as though once the timer is created, no global variables are updated within the update loop. If I make speed = 4 before allocating the CADisplayLink, the game runs at 4. However even if I make proper changes to speed it does not change. Anybody know why?

Answer 1

Okay, so the problem had to do with something larger than the context of which I originally thought it was on. The problem was that I wasn’t properly allocating things into memory, and because of that I was assigning to nil variables.