计时器可以在iOS 4.2上正常运行，但不能在iOS 5上运行

Question

In my app,

I have a 3 tab,

On the first tab I have a timer that is started when Start button is pressed.

When we come from the another tab, timer is not getting update.

For updating the timer, I use below code:

myticker = [NSTimer scheduledTimerWithTimeInterval:(1.0) target:self selector:@selector(ShowActicity) userInfo:nil repeats:YES];


 -(void)ShowActicity
 {
     Here I have the ticks,minute,hour  values   


      ticks =ticks + 1;
        if(ticks > 59)
        {
            minute = minute + 1;
            ticks = 0;
            if(minute > 59)
            {
                hour = hour + 1;
                minute = 0;
                if(hour > 23)
                {
                    hour = 0;
                }
            }
        }


        [lbl_timer setText:[NSString stringWithFormat:@"%02d:%02d:%02d",hour,minute,ticks]];


 }

My timer is updating fine with Base SDK iOS 4.2 but not working on iOS 5. What could be wrong?

Answer 1

THis may not be your problem but the selector is incorrect, from the Apple docs:

The selector must have the following signature:

- (void)timerFireMethod:(NSTimer*)theTimer

so your NSTimer call should be (notice the trailing ":"

myticker = [NSTimer scheduledTimerWithTimeInterval:(1.0) target:self selector:@selector(ShowActicity:) userInfo:nil repeats:YES];

and the target method have the signature:

- (void)ShowActicity:(NSTimer*)theTimer

Note, it is Objective-C convention to name methods with an initial lowercase letter, classes with a leading upper case character.

Answer 2

In 4.3 project main.m replace with ios5 main.m File. In appdelegate change the

   @interface SimpleTimerAppAppDelegate : NSObject 

with

  @interface SimpleTimerAppAppDelegate : UIResponder