title: my uilabel text can not change , why?
body: <p>lblOverlayView_text.text   do not change from   @"english subtitle"  to  @"change"; </p>
  
  <p>how to change, and why not ?</p>
  
  <pre><code>- (void)video123 {
  
  
  
      lblOverlayView = [[UILabel alloc] init];
      int height=40;
      lblOverlayView.frame = CGRectMake(0, 480-height, 320, height);
      lblOverlayView.backgroundColor = [UIColor grayColor];
      lblOverlayView.alpha = 0.5f;
      lblOverlayView.text = @"english subtitle";
      lblOverlayView.textColor=[UIColor greenColor];
      lblOverlayView.textAlignment=UITextAlignmentCenter;
  
  
  
  
  
      NSString *urlAddress=@"http://video.ted.com/talk/stream/2011U/Blank/MattCutts_2011U-320k.mp4";
  
       movieURL= [NSURL URLWithString:urlAddress];
  
      //MPMoviePlayerViewController *
      moviePlayer = [[MPMoviePlayerViewController alloc] initWithContentURL:movieURL];
  
  
  
      [moviePlayer.view addSubview:lblOverlayView];
  
  
      [self presentMoviePlayerViewControllerAnimated:moviePlayer];
  
  
      [NSThread detachNewThreadSelector:@selector(thread) toTarget:self withObject:nil];
  
      NSLog(@"loop test end playback starting...");
  
  }
  
  
  
  
  
  - (void) thread{
  
  
      NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  
  
     while (true) 
     {
          [NSThread sleepForTimeInterval: 0.2];
  
         lblOverlayView.text =  @"change";
  
      }
  
  
  
  
       [pool drain];
  }
  </code></pre>