UITableViewCell Scroll View - ios

Question

I have a table view cell with a scroll view for scrolling through images. There are a couple of issues I'm having with it.
When the table view is shown, the cell with the scroll view and images shows like the first image and part of the second image and the paging doesn't work and it lets you scroll in any direction.
Once I scroll past this cell and then scroll back to it, it is displayed correctly and paging works like it should.
In cellForRowAtIndexPath()
if indexPath.section == 0 {
let imageCell = tableView.dequeueReusableCellWithIdentifier("imageCell", forIndexPath: indexPath) as! ImageCell
imageCell.selectionStyle = .None
if imageFiles.count > 0 {
if imageFiles.count == 1 {
imageCell.pageControl.hidden = true
}
imageCell.pageControl.numberOfPages = imageFiles.count
imageCell.pageControl.currentPage = 0
var index = 0
for photo in imageFiles {
var frame = CGRect()
frame.origin.x = (imageCell.imageScrollView.frame.size.width * CGFloat(index))
frame.origin.y = 0
frame.size = CGSizeMake(imageCell.imageScrollView.frame.size.width, imageCell.imageScrollView.frame.size.height)
let imageView = UIImageView(frame: frame)
imageView.image = photo
imageCell.imageScrollView.addSubview(imageView)
imageCell.imageScrollView.contentSize = CGSizeMake(imageCell.imageScrollView.frame.size.width * CGFloat(imageFiles.count), imageCell.imageScrollView.frame.size.height)
index += 1
}
} else {
imageCell.pageControl.hidden = true
let imageView = UIImageView(frame: imageCell.imageScrollView.frame)
imageView.image = UIImage(named: "placeholder")
imageCell.imageScrollView.addSubview(imageView)
}
My custom cell:
import UIKit
class ImageCell: UITableViewCell, UIScrollViewDelegate {
#IBOutlet weak var pageControl: UIPageControl!
#IBOutlet weak var imageScrollView: UIScrollView!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
let pageWidth = scrollView.frame.size.width
pageControl.currentPage = Int(scrollView.contentOffset.x / pageWidth)
}
}

Answer 1

I was using SDWebImageDownloader. viewDidLoad() to download images to use in the scroll view but I wasn't reloading the table view data. Once I added that, this works perfectly.
func downloadImages() {
let downloader = SDWebImageDownloader.sharedDownloader()
for imageURL in images {
let url = NSURL(string: imageURL)
downloader.downloadImageWithURL(url, options: SDWebImageDownloaderOptions.UseNSURLCache, progress: nil,
completed: { (image, data, error, bool) -> Void in
self.imageFiles.append(image)
dispatch_async(dispatch_get_main_queue(), {
self.tableView.reloadData()
})
})
}
}

Answer 2

You are doing this:
frame.size = CGSizeMake(imageCell.imageScrollView.frame.size.width, imageCell.imageScrollView.frame.size.height)
I would guess that when your view initially loads, imageScrollView has not been fully laid out, so it doesn't have a valid size. Scrolling away from this cell & back to it after the view is fully loaded would result in the scroll view having a valid size.
You should validate that imageScrollView has the width you think it does, and if it doesn't, maybe use the width of the screen instead.
I have implemented a similar thing in one of my apps, so as another possible option, instead of putting a scroll view in your first cell, you could place a CollectionView in there instead and populate your collection view with cells of images. This would A) allow your layout to dynamically change with the view, and B) rather than loading up your scroll view with all the images, they can be dynamically loaded as needed.