StackView isHidden attribute not updating as expected

Question

I\'m trying to update a UIStackView so that a field displays, should the value of a UITextField equal \"Other\". Here is my code:

Answer 1

try to manipulate alpha along with isHidden property:

self.stackView.arrangedSubviews[3].isHidden = true
self.stackView.arrangedSubviews[3].alpha = 0

self.stackView.arrangedSubviews[3].isHidden = false
self.stackView.arrangedSubviews[3].alpha = 1

Answer 2

Updates on the user interface always have to be done on the main thread (THE LAW).

So wrap you UI updates on the main thead:

@IBOutlet var stackView: UIStackView!
func updateView() {
    print("UPDATING")
    UIView.animate(withDuration: 0.25, animations: { () -> Void in
        DispatchQueue.main.async {  // UI updates on the main thread
            if(self.myTextField.text! == "Other") {
                print("SHOWING")
                self.stackView.arrangedSubviews[3].isHidden = false
             } else {
                print("HIDING")
                self.stackView.arrangedSubviews[3].isHidden = true
             }
             print("Is hidden: \(self.stackView.arrangedSubviews[3].isHidden )")
        }
    })

Answer 3

It's known UIStackView bug (http://www.openradar.me/25087688). There is a thread on SO about it: (Swift: Disappearing views from a stackView). Long story short:

The bug is that hiding and showing views in a stack view is cumulative. Weird Apple bug. If you hide a view in a stack view twice, you need to show it twice to get it back.

To fix this issue you can use following extension:

extension UIView {
    var isHiddenInStackView: Bool {
        get {
            return isHidden
        }
        set {
            if isHidden != newValue {
                isHidden = newValue
            }
        }
    }
}