NavigationBar隐藏UICollectionView中的单元格

Question

我正在尝试使用单元格创建CollectionView。然而，它似乎一直隐藏在第一个细胞的顶部。当然，我可以设置顶级插图，但是，还有其他方法可以做到，或者我做错了什么？

我已经创建了一个UICollectionViewController并设置了以下内容。

override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath, object: PFObject!) -> PFCollectionViewCell? {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("ItemCell", forIndexPath: indexPath) as? BrowseCell

    cell?.titleLabel.text = object["title"] as! NSString as String
   // cell?.myImageView.file = (object["images"] as [PFFile]).first
    cell?.clipsToBounds = true

    return cell
}

override func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAtIndex section: Int) -> CGFloat {
    return 10
}

override func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets {
    return UIEdgeInsetsMake(0, 10, 0, 10)
}
override func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
    return CGSizeMake(self.view.frame.width/2-15, 100)
}

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