Dynamic cell height with SDWebImage - ios

Question

I have a table view and table view cells with an image view on them. I want them to have a fixed width but with a dynamic height (depending on the image coming in from the server).
I am using SDWebImage to download and set the image, but the table view cells are turning out very weird.
I didn't forget to:
postTableView.estimatedRowHeight = UITableViewAutomaticDimension
postTableView.rowHeight = UITableViewAutomaticDimension
cellForRow method:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "postCell", for: indexPath) as! TableViewCell
let post = postArray[indexPath.row]
cell.setupCell(with: post)
return cell
}
Table view cell class:
class TableViewCell: UITableViewCell {
#IBOutlet weak var postTitle: UILabel!
#IBOutlet weak var postSource: UILabel!
#IBOutlet weak var postChart: UIImageView!
internal var aspectConstraint: NSLayoutConstraint? {
didSet {
if oldValue != nil {
postChart.removeConstraint(oldValue!)
}
if aspectConstraint != nil {
postChart.addConstraint(aspectConstraint!)
}
}
}
override func awakeFromNib() {
super.awakeFromNib()
selectionStyle = UITableViewCellSelectionStyle.none
}
override func prepareForReuse() {
super.prepareForReuse()
postChart.image = nil
aspectConstraint = nil
}
func setupCell(with post: Post) {
postTitle.text = post.title
postSource.text = post.source
let tempImageView = UIImageView()
tempImageView.sd_setImage(with: URL(string: post.chartURL!), placeholderImage: UIImage(named: "placeholder.png")) { (image, error, cache, url) in
if let image = image {
self.setCustomImage(image: image)
}
}
}
func setCustomImage(image: UIImage) {
let aspect = image.size.width / image.size.height
let constraint = NSLayoutConstraint(item: postChart, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: postChart, attribute: NSLayoutAttribute.height, multiplier: aspect, constant: 0.0)
constraint.priority = UILayoutPriority(rawValue: 999)
aspectConstraint = constraint
postChart.image = image
setNeedsLayout()
}
}

Answer 1

You just need to tell the whole tableView to refresh its view. Use this code in the view controller holding the tableView:
func refreshTableView() {
self.tableView.beginUpdates()
self.tableView.setNeedsDisplay()
self.tableView.endUpdates()
}
Using a delegate pattern tell the viewController to refresh the tableView, so something like:
func setCustomImage(image: UIImage) {
let aspect = image.size.width / image.size.height
let constraint = NSLayoutConstraint(item: postChart, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: postChart, attribute: NSLayoutAttribute.height, multiplier: aspect, constant: 0.0)
constraint.priority = UILayoutPriority(rawValue: 999)
aspectConstraint = constraint
postChart.image = image
// call this to refresh table
delegate.refreshTableView()
}
Post class:
class Post {
var title : String?
var source : String?
var chartURL : String?
var postChart: UIImage?
var category : String?
var rank : CGFloat?
var imageSize: CGSize?
init(data: NSDictionary) {
title = data["title"] as? String
source = data["source"]as? String
chartURL = data["chartURL"] as? String
postChart = data["postChart"] as? UIImage
category = data["category"] as? String
rank = data["rank"] as? CGFloat
}
}