Question

I have a NSDate variable. From that variable, how I can show a stopwatch that continuously updates in the view?

I’ve tried [NSTimer scheduledTimerWithTimeInterval] but can’t get it working but also doubt that is the ideal way to do that.

Answer 1

Try this

- (void)updateTimer
{
    static NSInteger counter = 0;
    [stopWatchLabel setText:[NSString stringWithFormat:@"Counter: %i", counter++]];
}

- (IBAction)onStartPressed:(id)sender {
    startDate = [[NSDate date]retain];

    // Create the stop watch timer that fires every 10 ms
    stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0
                                                      target:self
                                                    selector:@selector(updateTimer)
                                                    userInfo:nil
                                                     repeats:YES];
}

You have to connect the IBAction to a button, and the stopWatchLabel to a UILabel in the interface builder.

Found on: http://www.apptite.be/tutorial_ios_stopwatch.php