CODEWITHSUNDEEP
iosobjective-cuilabelnstimer
user2000452
user2000452

Reputation:

UILabel updating incorrectly with NSTimer

I am showing a count down timer using UILabel and NSTimer -

-(void)a_Method
{
    [coolTimeLbl setNeedsDisplay];
    coolTime = 5;  // it is an int
    coolingTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(cooling) userInfo:nil repeats:YES];  // NSTimer
}

-(void)cooling
{
    if (coolTime>0) 
    {
        coolTime = coolTime-1;

        NSLog(@" coolTime----%@",coolTime);
        coolTimeLbl.text =[NSString stringWithFormat:@"%d",coolTime];
        NSLog(@" coolTimeLbl----%@",coolTimeLbl.text);
    }
    else
    {     
        [coolingTimer invalidate];
        coolingTimer = nil;
    }
}

The first time everything works fine and I am getting coolTimeLbl.text as - 4 3 2 1 0

But the second time when I call aMethod, coolTimeLbl is not getting updated properly - it is like 3 2 0 etc (some weird behavior)
However both NSLogs (coolTime & coolTimeLbl) print perfectly all the times and values.

Why does this happen? I tried many ways like NSNotification etc. Please help me to fix this.

Upvotes: 0

Views: 120

Answers (2)

guido
guido

Reputation: 2896

Had the same issue in one of my viewControllers and another one was working OK with same NSTimer code. Looked at about 20 SO threads to get it solved. No luck. In my case 

myLabel.opaque = false

solved it. Don't ask me why.

Upvotes: 0

EDUsta
EDUsta

Reputation: 1933

If you're calling a_Method more than once before coolingTimer invalidates itself, the timer will tick more than once.

You should add some boolean like ;

BOOL isTimerValid;

in a_Method,

if(!isTimerValid)
{     
    isTimerValid = YES;
    coolingTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(cooling) userInfo:nil repeats:YES];  // NSTimer
}

in cooling,

else
{
    isTimerValid = NO;
    ....
}

Upvotes: 1

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