title: NSTimer not working on StopWatch App ONLY ON SIMULATOR (Shows static strange number)
body: <p>When I click on Start the <code>stopWatchLabel</code> shows the following (its static, nothings runs):</p>
  
  <ul>
  <li>NOTE: When I test this app on my iPhone all runs as expected. No problems at all.</li>
  </ul>
  
  <p>Can someone explain why?</p>
  
  <p><img src="https://i.stack.imgur.com/if9pf.png" alt="enter image description here"></p>
  
  <p>.h</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
  @interface ViewController : UIViewController
  {
      NSTimer *stopWatchTimer; 
      NSDate *startDate;
  }
  
  
  @property (strong, nonatomic) IBOutlet UILabel *stopWatchLabel;
  
  - (IBAction)startButtonTapped:(id)sender;
  
  - (IBAction)stopButtonTapped:(id)sender;
  
  -(void)updateTimer;
  
  @end
  </code></pre>
  
  <p>.m</p>
  
  <pre><code>- (IBAction)startButtonTapped:(id)sender {
  
      stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 
                                                        target:self 
                                                      selector:@selector(updateTimer) 
                                                      userInfo:nil 
                                                       repeats:YES];
  }
  
  
  - (void)updateTimer
  {
      NSDate *currentDate = [NSDate date];
      NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
      NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
  
      NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
      [dateFormatter setDateFormat:@"HH:mm"];
      [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
  
      NSString *timeString=[dateFormatter stringFromDate:timerDate];
      stopWatchLabel.text = timeString;
  }
  
  
  - (IBAction)stopButtonTapped:(id)sender {
  
      [stopWatchTimer invalidate];
  }
  </code></pre>