title: NSNotificationCenter applicationDidBecomeActiveNotification not working iOS 9
body: <p>I'am trying to call a function when the app com back to Foreground by applicationDidBecomeActiveNotification. I have it in iOS 8 and iOS 7 and it works well. But not in iOS 9 ? It docent call first time you open the app</p>
  
  <pre><code>-(void) viewWillAppear:(BOOL)animated {
  
  [[NSNotificationCenter defaultCenter]
   addObserver:self
   selector:@selector(applicationDidBecomeActiveNotification:)
   name:UIApplicationDidBecomeActiveNotification
   object:[UIApplication sharedApplication]]; 
  
  }
  
  - (void)applicationDidBecomeActiveNotification:(NSNotification *)notification {
  
  //stuff
  
  }
  </code></pre>
  
  <p>It is every notification center that is not calling at startup...</p>