title: view controller variables in ApplicationWillResignActive
body: <p>I'm trying to make my timer "run" in the background by saving the time to disk on entering background and retrieving it on entering foreground. Each view controller has a timer and a timeInterval specified by the user. The problem is, I don't know how to access the timeInterval variable. I think I can get the difference of time by using something like this (would this work?):</p>
  
  <pre><code>NSTimeInterval idleTime = [dateReturnedToForeground timeIntervalSinceDate:dateEnteredBackground];
  NSTimeInterval elapsedTime = [[NSDate date] timeIntervalSinceDate:startDate];
  elapsedTime -= idleTime;
  </code></pre>
  
  <p>Each view controller (and timer/time interval) is accessed like this:</p>
  
  <pre><code>-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
      DetailViewController *detailVC;
      if (![self.detailViewsDictionary.allKeys containsObject:indexPath]){
          detailVC = [[DetailViewController alloc]initWithNibName:@"DetailViewController" bundle:nil];
          [self.detailViewsDictionary setObject:detailVC forKey:indexPath];
          detailVC.context = self.managedObjectContext;
      }else{
          detailVC = self.detailViewsDictionary[indexPath];
      }
          Tasks *task = [[self fetchedResultsController] objectAtIndexPath:indexPath];
          detailVC.testTask = task;
          [[self navigationController] pushViewController:detailVC animated:YES];
      NSLog(@"%@", self.detailViewsDictionary);
      [[NSNotificationCenter defaultCenter] addObserver:detailVC forKeyPath:self.detailViewsDictionary[indexPath] options:nil context:nil];
  }
  </code></pre>
  
  <p>I am adding each view controller to the Notification Center so it can be accessed in the app delegate (i think this is right?). Problem is, I don't know how to combine the first code with the view controller code, because I can't access the view controller's properties in the app delegate. Any suggestions so that I can make my timer "run" in the background?</p>