I've got a problem that only seems to occur on the device, not in the simulator.

My app's animation is started and stopped using these methods:

NSTimer* animationTimer;

-(void)startAnimation
{
    if(animationTimer = nil)
        animationTimer = [NSTimer scheduledTimerWithTimeInterval:1.0f/60.0f target:self selector:@selector(drawView) userInfo:nil repeats:YES];
}

-(void)stopAnimation
{
    [animationTimer invalidate];
    animationTimer = nil;
}

In the simulator this works fine and drawView starts being called at 60fps. On the device (testing on iPod Touch), the scheduleTimerWithTimeInterval method doesn't seem to work. Furthermore, [animationTimer invalidate] causes EXC_BAD_ACCESS.

I've spotted an obvious but minor flaw; adding if(animationTimer != nil) to the stopAnimation method will prevent the crash, but doesn't solve the problem of the animation timer not being properly initialised.

Edit: The above doesn't prevent a crash. animationTimer != nil yet calling invalidate causes EXC_BAD_ACCESS.

Should also add, this problem doesn't occur all the time on the device. Maybe 40% of the time.