title: UIScrollView delegate methods not calling properly
body: <p>In order to scroll up and down i need to call two methods  for that I have used the below method .I am using <strong>scrollview delegate method</strong> for <code>UICollection</code> as it is the subview for <code>UIScrollView</code>.Here is the code that I have written but the scroll is not easily moving  and the result is also not accurate for some times can any one suggest.?</p>
  
  <pre><code>- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
      CGPoint mScrollPosition = [scrollView.panGestureRecognizer velocityInView:mCollectionView];
  
  
      if (mScrollPosition.y &gt; 0.0f){
          NSLog(@"going down");
         //Action One
          mYearHeaderTitle--;
          [self.mCollectionView reloadData];
  
      }
      else if (mScrollPosition.y &lt; 0.0f){
          NSLog(@"going up");
        //Action two
          mYearHeaderTitle++;
          [self.mCollectionView reloadData];
      }
  }
  </code></pre>