title: UICollectionView does not scroll
body: <p>I have a <code>UICollectionView</code> set up with a <code>UICollectionViewDataSource</code> that currently provides six items.
  These are fewer than needed to fill the screen. The problem is that my collection view only scrolls when there are enough items to fill the screen (tested with 10, 20).
  When displaying fewer items it wont even do this bounce animation I am trying to get, it's just fixed.</p>
  
  <pre><code>- (void)viewWillAppear:(BOOL)animated
  {
      [super viewWillAppear:animated];
  
      [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateCollectionViewData) name:UIDocumentStateChangedNotification object:nil];
  
      UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc]init];
      flowLayout.itemSize = CGSizeMake(160, 100);
      flowLayout.minimumInteritemSpacing = 0;
      flowLayout.minimumLineSpacing = 0;
  
      self.collectionView = [[UICollectionView alloc]initWithFrame:self.view.bounds collectionViewLayout:flowLayout];
      [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"Cell"];
      self.collectionView.delegate = self;
      self.collectionView.dataSource = self;
      self.collectionView.bounces = YES;
      [self.view addSubview:self.collectionView];
  }
  
  - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
      return [self.collectionViewData count];
  }
  - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
  {
       UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
  
      Expense *expense = [self.collectionViewData objectAtIndex:indexPath.row];
  
      UILabel *label = [[UILabel alloc]initWithFrame:cell.bounds];
      label.text = expense.value;
      label.backgroundColor = [UIColor clearColor];
      label.font = [UIFont fontWithName:@"Miso-Bold" size:30];
      label.textAlignment = NSTextAlignmentCenter;
      [cell addSubview:label];
  
      cell.backgroundColor = [UIColor colorWithRed:1 - (indexPath.row / 30.0f) green:0 blue:1 alpha:1];
  
      return cell;
  }
  </code></pre>
  
  <p>Thanks for your help!</p>