title: How do i create a countdown timer in xcode 4.5
body: <p>Ok i want to create MULTIPLE timers that all start at a different time (25, 50,1 min, 1min 30s...) but i dont know how to make it stop when it reaches 0 and when it does reach zero, bring the "Player" to another view.</p>
  
  <p>Heres my .h file</p>
  
  <pre><code>@interface ViewController :UIViewController {
  
  IBOutlet UILabel *seconds;
  
  NSTimer *timer;
  
  int MainInt;
  }
  
  @end
  </code></pre>
  
  <p>And heres my .m file</p>
  
  <pre><code>@implementation ViewController
  
  -(void)countDownDuration {
  
  MainInt -= 1;
  
  seconds.text = [NSString stringWithFormat:@"%i", MainInt];
  
  }
  
  -(IBAction)start:(id)sender {
  
  MainInt = 25;
  
  timer = [NSTimer scheduledTimerWithTimeInterval:1.0
  
                                           target:self
                                         selector:@selector(countDownDuration)
                                         userInfo:nil
                                          repeats:YES];
  }
  
  @end
  </code></pre>