title: Key-Value observing not working IOS
body: <p>Hi I am developing IOS application in which I am using add observer with key value pair. But it's not working. I did following things:</p>
  
  <pre><code>[self.scrollView addObserver:self
                    forKeyPath:@"new"
                       options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld)
                       context:nil];
  
  - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
  
      // inside here ... 
  }
  </code></pre>
  
  <p>But its not calling the above method. If I change <code>forKeyPath</code> to <code>contentOffset</code> then its working fine. But I want to change that value. Am I doing something wrong? Need Help. Thank you.</p>