title: UIScrollView will not zoom
body: <p>I have a subclassed <code>UIView</code> which I can get to scroll but not to zoom. I'm using autolayout so wondered if anything had changed in IOS6. In particular when are the <code>scrollViewWillBeginZooming</code> and <code>scrollViewDidEndZooming</code> methods implemented. My code looks like</p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
  
      self.ringSet2 = [[RingView alloc] initWithFrame:CGRectMake(0, 0, 800, 800)];
      [self.ringSet2 setDefaults];
  
      /// ... more setup for other views but only ringSet2 is scrolled.
  
      self.scrollview1.delegate=self;
      self.scrollview1.scrollEnabled=YES;
      self.scrollview1.contentSize=self.ringSet2.bounds.size
  
      self.scrollview1.minimumZoomScale=0.2;
      self.scrollview1.maximumZoomScale=5.0;
  
      self.ringSet2.userInteractionEnabled=YES;
  
      // ... needed elsewhere so other views can pick up their dimensionts 
  
      [self.view setNeedsLayout];
      [self.view layoutIfNeeded];
  
      /// ... code for additional views
  
      [self.scrollview1 zoomToRect:CGRectMake(0, 0, 200, 200) animated:YES];
      [self.scrollview1 addSubview:self.ringSet2];
  
  }
  </code></pre>
  
  <p>with </p>
  
  <pre><code>-(UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView{
      return self.ringSet2;
  }
  </code></pre>
  
  <p>and <code>scrollViewWillBeginZooming</code> etc. implemented just to trace what is happening. Interesting, 
  <code>viewForZoomingInScrollView</code> appears to get called only once, as is <code>scrollViewDidEndZooming</code> with  a scale value just under one but <code>scrollViewWillBeginZooming</code> is never called. The property ringSet2 is defined</p>
  
  <pre><code>@property (strong, nonatomic) IBOutlet RingView *ringSet2;
  </code></pre>
  
  <p>as the view does not appear if it's defined as weak.</p>