Swift: How can I bind data to a view in a loop? - ios

Question

I want to bind data to an array of UIImageView-es by for-loop. But I don't know how to bind as simple as Javascript data attribute.
I have an idea that making an array [UIImage : data] to do this.
Ok, here is something wrong with my code:
Questions:
How to get its patternSelector in selectDecoration?
How to create outlets binding with data in a loop? For example, How can I bind every variable pattern to each action selectDecoration() ?
func selectDecoration(recognizer: UITapGestureRecognizer) {
print("OK")
}
let patternSelectorHeight: CGFloat = 120
var i : Int = 0
//var patternViews = [UIImageView]()
for pattern in decorationPatterns {
let patternSelector = UIImageView(image: UIImage(named: "test.jpg"))
if let p = patternSelector.image {
let proportion = p.size.width / p.size.height
let w = proportion * patternSelectorHeight
let patternX: CGFloat = (w + Conf.Size.margin) * CGFloat(i) + Conf.Size.margin
let patternOrigin = CGPoint(x: patternX, y: decorationSelectionTitleHeight)
patternSelector.userInteractionEnabled = true
patternSelector.frame = CGRect(origin: patternOrigin, size: CGSize(width: w, height: patternSelectorHeight))
patternSelector.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "selectDecoration:"))
decorationBg.addSubview(patternSelector)
decorationBg.bringSubviewToFront(patternSelector)
//patternViews.append(patternSelector)
}
i++
}

Answer 1

There is no inbuilt support for data binding in Swift. You need to keep a reference to your UIImageView objects, probably, as you suggest, in an array, so that you can update them later.
You need to set patterSelector.userInteractionEnabled=true for the UITapGestureRecognizer to work.
let patterSelectorSize = CGSize(width: 80.0, height: 160.0)
var imageViews = [UIImageView]() // This probably needs to be an instance variable so you can access it outside of this function
var i : Int = 0
for _ in decorationPatterns {
let patternX: CGFloat = (patterSelectorSize.width + 10) * CGFloat(i) + 10
let patternOrigin = CGPoint(x: patternX, y: CGFloat(60))
let patterSelector = UIImageView(image: UIImage(named: "default.jpeg"))
patterSelector.frame = CGRect(origin: patternOrigin, size: patterSelectorSize)
patterSelector.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "selectDecoration:"))
patterSelector.userInteractionEnabled=true
imageViews.append(patterSelector)
decorationBg.addSubview(patterSelector)
decorationBg.bringSubviewToFront(patterSelector)
i++
}
You must also ensure that userInteractionEnabled is true in decorationBg otherwise touches won't be propagated to your image views

Answer 2

(1) How to create outlets binding with data in a loop?
If you would like to bind String data then try accessibilityLabel property. You can set & retrieve value silently.
(2) why the UITapGestureRecoginzer in follow doesn't work at all?
You missed to enable the userInteractionEnabled of your UIImageView
Hope this helps you.