Trying to deactive NSTimer - objective-c

Question

I am using NSTimer to run a loop for counting down, then at some point(clicking 'start') I need to run this once again. The first Timer isn't stopped though so countdown pace increases with every run of the function
- (IBAction)startbutton:(id)sender {
timeTick = arc4random_uniform(7)+3;
timeofstart = CACurrentMediaTime();
chosentime = timeTick;
NSLog(#"chosentime værdien er %f", chosentime);
[timer invalidate];
timer = nil;
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(tick) userInfo:nil repeats:YES];
}
- (void) tick {
if (timeTick == 0) {
winnerlabel2.text = #"GO !!!";
}
else {
timeTick --;
NSLog(#"%f", timeTick);
}
}

Answer 1

Here, it is unclear what timer is referring to in these first 2 lines. This 3rd line is creating a new local variable. It looks like you must have an instance variable timer that is created somewhere else. You are invalidating that timer, but then creating a new timer as a local variable that has no permanent handle (because it dies after going out of scope at the end of this method call) and thus every timer after the first never gets invalidated.
[timer invalidate];
timer = nil;
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(tick) userInfo:nil repeats:YES];
Change this 3rd line from...
NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(tick) userInfo:nil repeats:YES];
to...
timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:#selector(tick) userInfo:nil repeats:YES];