UITableViewCell subclass with Auto Layout constraints incorrect height - swift

Question

I have a UITableViewCell subclass, which I setup the views all in code and than add NSLayoutConstraints to. Everything is working, except my UITabbleViewCell is not calculating its height correctly.
Here is the code of the UITableViewCell
override func updateConstraints() {
setupThumbnailImages()
super.updateConstraints()
}
func setupThumbnailImages() {
var imageViewXOrigin : CGFloat = 5.0
var imageViewYOrigin : CGFloat = 0.0
for thumbnailUrl in self.thumbnailsUrlArray {
let miniPictureView = UIImageView()
miniPictureView.backgroundColor = UIColor.blueColor()
miniPictureView.contentMode = UIViewContentMode.ScaleAspectFill
miniPictureView.clipsToBounds = true
miniPictureView.frame = CGRectMake(0, 0, 0, 0)
miniPictureView.translatesAutoresizingMaskIntoConstraints = false
if((imageViewXOrigin + 50) > frame.size.width){
imageViewYOrigin += 50
imageViewXOrigin = 5
}
contentView.addSubview(miniPictureView)
contentView.addConstraint(NSLayoutConstraint(item: miniPictureView, attribute: .Leading, relatedBy: .Equal, toItem: contentView, attribute: .Leading, multiplier: 1, constant: imageViewXOrigin))
contentView.addConstraint(NSLayoutConstraint(item: miniPictureView, attribute: .Top, relatedBy: .Equal, toItem: contentView, attribute: .Top, multiplier: 1, constant: imageViewYOrigin))
contentView.addConstraint(NSLayoutConstraint(item: miniPictureView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .Height, multiplier: 1, constant: 50))
contentView.addConstraint(NSLayoutConstraint(item: miniPictureView, attribute: .Width, relatedBy: .Equal, toItem: nil, attribute: .Width, multiplier: 1, constant: 50))
let lastImage = thumbnailsUrlArray.last
if (lastImage == thumbnailUrl){
contentView.addConstraint(NSLayoutConstraint(item: miniPictureView, attribute: .Bottom, relatedBy: .Equal, toItem: contentView, attribute: .Bottom, multiplier: 1, constant: 0))
}
imageViewXOrigin += 50
}
contentView.translatesAutoresizingMaskIntoConstraints = false
contentView.addConstraint(NSLayoutConstraint(item: contentView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .Height, multiplier: 1, constant: imageViewYOrigin))
}
What happens is the miniPictureView displays as it should, however its displayed outside of the UITableViewCell's bounds and the cell stays at a height of 44.

Answer 1

If you want the cell to size itself based on its contents, make sure you set the following on your UITableView:
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 44.0 // Or any other estimate you want, just make sure to set this to some value
A couple more notes:
Your miniPictureView constraints should be added to miniPictureView itself, since they don't involve contentView or a sibling view
In order for self-sizing to work, you also have to have a complete chain of constraints from the top of the contentView to the bottom. So you should add an equality constraint between the bottom of miniPictureView and contentView so there is a constraint that will actually push the bottom of the content view.
I suspect your last two lines aren't helping. The contentView's height should be established by its top and bottom edges being constrained to its contents. And the autoresizing mask is used to scale the cell and its contentView together. If you set that to false, you should at least replace it with code that sets the cell's frame to be equal to the contentView frame AFTER the layout is calculated.