UILabel takes long to load swift - ios

Question

I'm trying to create a view of a "match" image and the "match price" label in the top right corner of the match image. So far everything works fine- I create the image in the container view, I create a UIImageView for the background of my price label, but when I create the actual label and customize it, it takes forever to load in my app (that is to say, everything loads- the match image, the price label background image, but not the actual label detailing the price). Can anyone spot where in my code I'm going wrong?
func setupMiniContentScroll(contentScroll: UIScrollView) {
let scalar:Double = 6/19
let contentViewDimension = contentScroll.frame.width * CGFloat(scalar)
let contentScrollWidth = CGFloat(LocalUser.matches.count) * (contentViewDimension + CGFloat(12)) - CGFloat(12)
contentScroll.backgroundColor = UIColorFromHex(0x34495e)
for index in 0..<LocalUser.matches.count {
let match = LocalUser.matches[index]
MatchesManager.globalManager.retrieveMatchThumbnail(match) { img, error in
if let img = img {
//create the mini matches views
let xOrigin = index == 0 ? 12 : CGFloat(index) * contentViewDimension + (CGFloat(12) * CGFloat(index) + CGFloat(12))
let contentFrame = CGRectMake(xOrigin, 10, contentViewDimension, contentViewDimension)
let contentView = self.makeMiniContentView(contentFrame, image: img, matchedPrice: match.matchedPrice)
contentView.match = match
let tap = UITapGestureRecognizer(target: self, action: #selector(BrowseViewController.toggleItemInfo(_:)))
contentView.addGestureRecognizer(tap)
//update the contentScrollView
dispatch_async(dispatch_get_main_queue()) {
contentScroll.addSubview(contentView)
contentScroll.contentSize = CGSizeMake(contentScrollWidth + CGFloat(16), contentScroll.frame.height)
}
}
}
}
}
//functions to create labels and imgViews for MiniMyMatches
func makeMiniContentView(frame: CGRect, image: UIImage, matchedPrice: Int) -> ItemContainer {
let containerView = ItemContainer(frame: frame)
//create the item image
let imgView = UIImageView(frame: CGRect(x: 0, y: 0, width: containerView.frame.width, height: containerView.frame.height))
imgView.image = image
imgView.layer.cornerRadius = 5
imgView.layer.masksToBounds = true
imgView.userInteractionEnabled = true
//create the price label
dispatch_async(dispatch_get_main_queue()) {
let priceLabel = self.makeMiniPriceLabel(containerView, matchedPrice: matchedPrice)
containerView.addSubview(imgView)
containerView.addSubview(priceLabel)
}
return containerView
}
func makeMiniPriceLabel(containerView: ItemContainer, matchedPrice: Int) -> UIView {
//price label var
let priceLabelFrame = CGRectMake(containerView.frame.size.width - 35, -7, containerView.frame.size.width * 0.50, containerView.frame.size.height * 0.35)
//create the price container
let priceContainer = UIImageView(frame: priceLabelFrame)
priceContainer.image = UIImage(named: "venn.png")
//create the price label
let priceLabel = UILabel(frame: CGRect(x: 3, y:0, width: priceContainer.frame.width, height: priceContainer.frame.height))
priceLabel.text = "$\(matchedPrice)"
priceLabel.numberOfLines = 1
priceLabel.textColor = UIColor.whiteColor()
priceLabel.font = priceLabel.font.fontWithSize(20)
priceContainer.addSubview(priceLabel)
return priceContainer
}

Answer 1

My guess is that the closure for your retrieveMatchThumbnail function is being called on a background thread. You have code in that closure that is manipulating UI objects. I would move ALL the UI code inside your call to dispatch_async():
MatchesManager.globalManager.retrieveMatchThumbnail(match) { img, error in
if let img = img {
//create the mini matches views
let xOrigin = index == 0 ? 12 : CGFloat(index) * contentViewDimension + (CGFloat(12) * CGFloat(index) + CGFloat(12))
let contentFrame = CGRectMake(xOrigin, 10, contentViewDimension, contentViewDimension)
//update the contentScrollView
dispatch_async(dispatch_get_main_queue()) {
let contentView = self.makeMiniContentView(contentFrame, image: img, matchedPrice: match.matchedPrice)
contentView.match = match
let tap = UITapGestureRecognizer(target: self, action: #selector(BrowseViewController.toggleItemInfo(_:)))
contentView.addGestureRecognizer(tap)
contentScroll.addSubview(contentView)
contentScroll.contentSize = CGSizeMake(contentScrollWidth + CGFloat(16), contentScroll.frame.height)
}
}
}