iOS13.1 UIAlertController with preferedStyle: .actionSheet cannot change title's text color and font - uialertcontroller

Question

I change title font and color like this:
let titleAttributes = [NSAttributedStringKey.font: UIFont(name: "HelveticaNeue-Bold", size: 25)!, NSAttributedStringKey.foregroundColor: UIColor.purple]
alert.setValue(titleString, forKey: "attributedTitle")
Before iOS13 this worked fine both for preferredStyle .alert and .actionSheet.
Now it only works for .alert and doesn't work for .actionSheet.
Someone please any help?

Answer 1

iOS 13 now embeds the UIAlertController title in a UIVisualEffectView, and only the title's alpha channel affects its appearance. If it is critical to control the exact color, I think you could try finding the subview class _UIInterfaceActionGroupHeaderScrollView, remove its child UIVisualEffectView, and then add your own UILabel back in. But no guarantees it will work or that it won't trigger a crash. You can use the allSubviews extension below and compare each to this:
let grpHeader = NSClassFromString("_UIInterfaceActionGroupHeaderScrollView")
Or if you just need to ensure that your title is visible based on your app's color scheme I had success with the following, which should be quite safe to use at least until iOS 14 is released.
let alertController = UIAlertController(....)
for subView in UIView.allSubviews(of: alertController.view) {
if let effectView = subView as? UIVisualEffectView {
if effectView.effect is UIVibrancyEffect {
if #available(iOS 13.0, *) {
// iOS 13.1 default blur style is UIBlurEffectStyleSystemVibrantBackgroundRegular which is NOT currently defined anywhere
// if your alert controller color is dark, set to .systemMaterialDark
// if your alert controller color is light, set to .systemMaterialLight
effectView.effect = UIVibrancyEffect(blurEffect: UIBlurEffect(style: UIBlurEffect.Style.systemMaterialDark), style: .secondaryLabel)
}
break
}
}
}
// You will need this UIView category to get an array of all subviews,
// as the view heirarchy is complex. In iOS13 it is:
// UIAlertController.UIView ->
// _UIAlertControllerInterfaceActionGroupView ->
// UIView
// _UIInterfaceActionGroupHeaderScrollView
// ** UIVisualEffectView **
// _UIInterfaceActionRepresentationsSequenceView
// _UIDimmingKnockoutBackdropView ]
// ** all your button actions **
extension UIView {
class func allSubviews<T : UIView>(of view: UIView) -> [T] {
var subviews = [T]()
for subview in view.subviews {
subviews += allSubviews(of: subview) as [T]
if let subview = subview as? T {
subviews.append(subview)
}
}
return subviews
}
}