title: UICollectionView's cellForItemAtIndexPath is not being called
body: <p>Only my second time using UICollectionView's and perhaps I have bitten off more than I can chew but nevertheless:</p>
  
  <p>I am implementing a UICollectionView (myCollectionView) that uses custom UICollectionViewCell's that I have subclassed.  The subclassed cells (FullReceiptCell) contain UITableView's and are the size of the viewcontroller.  I am trying to allow for horizontal scrolling between the FullReceiptCells.</p>
  
  <p>The subclassed UICollectionViewController that contains myCollectionView is being pushed on to a nav controller stack.  Currently, myCollectionView loas and horizontal scrolling is enabled.  However, no cells are visible.  I have confirmed that </p>
  
  <pre><code>- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
  </code></pre>
  
  <p>has run and is returning an integer greater than 0.  I have also confirmed that myCollectionView's delegate and datasource are properly set in IB to the subclassed UICollectionViewController. </p>
  
  <p>The method where the cells are to be loaded: </p>
  
  <pre><code>- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
  </code></pre>
  
  <p>is not being called.</p>
  
  <p>Here is where I push the UICollectionViewController and my viewDidLoad method within that controller (NOTE: initWithBill is an override of the normal initializer):</p>
  
  <p>In the prior ViewControllers .m file:</p>
  
  <pre><code>FullReceiptViewController *test = [[FullReceiptViewController alloc] initWithBill:currentBill];
  test.title = @"Review";
  [self.navigationController pushViewController:test animated:YES];
  </code></pre>
  
  <p>In FullReceiptViewController.m:</p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
      // Do any additional setup after loading the view from its nib.
      [self.myCollectionView registerClass:[FullReceiptCell class] forCellWithReuseIdentifier:@"FullReceiptCellIdentifier"];
      self.myCollectionView.pagingEnabled = YES;
      // Setup flowlayout
  
      self.myCollectionViewFlowLayout = [[UICollectionViewFlowLayout alloc] init];
      [self.myCollectionViewFlowLayout setItemSize:CGSizeMake(320, 548)];
      [self.myCollectionViewFlowLayout setSectionInset:UIEdgeInsetsMake(0, 0, 0, 0)];
      [self.myCollectionViewFlowLayout setScrollDirection:UICollectionViewScrollDirectionHorizontal];
      self.myCollectionViewFlowLayout.minimumLineSpacing = 0;
      self.myCollectionViewFlowLayout.minimumInteritemSpacing = 0;
      [self.myCollectionView setCollectionViewLayout:myCollectionViewFlowLayout];
      //testing to see if the collection view is loading
      self.myCollectionView.backgroundColor = [UIColor colorWithWhite:0.25f alpha:1.0f];
  </code></pre>
  
  <p>Any clue as to why it is not being called?</p>