title: Two UIScrollViews, synchronous scrolling
body: <p>I heve two UIScrollViews, they are on top of each other.</p>
  
  <pre><code>                                        UIView
                                             |
                                --------------------------
                                |                        |
                           UIScrollView1            UIScrollView2
  </code></pre>
  
  <p>I would like it, to work in the following way. If I scroll UIScrollView2, UIScrollView1 should also scroll by the same contentOffset. It must by done synchronously, so using <code>scrollViewDidScroll</code> is not an option. Do you guys have some idea, how can it be done?</p>
  
  <p>Source Code</p>
  
  <pre><code>    _prContentGridView = [[PRContentGridView alloc] initWithFrame:frame];
      _prContentGridView.minimumZoomScale = 0.25;
      _prContentGridView.maximumZoomScale = 2.0;
      _prContentGridView.delegate = self;
  
      _prBackgroundGridView = [[PRBackgroundGridView alloc] initWithFrame:frame];
  
      [self addSubview:_prBackgroundGridView];
      [self addSubview:_prContentGridView];
  </code></pre>
  
  <p>Delegate Method</p>
  
  <pre><code>- (void)scrollViewDidScroll:(UIScrollView *)scrollView
  {
      if (_prContentGridView.scrollEnabled == YES) {
          CGPoint p = CGPointMake(scrollView.contentOffset.x -   _prevousContentOffsetOfContentScrollView.x, scrollView.contentOffset.y - _prevousContentOffsetOfContentScrollView.y);
          [_prBackgroundGridView setContentOffset:p animated:YES];
      }
  }
  </code></pre>