In Swift, how do you find UILayoutGuide objects in a view controller? - swift

Question

I'm creating a sudoku style swift app using 81 buttons (organized in stack views). I'm referencing the buttons using their tag value 0 to 80 which aligns with the arrays I'm using to store the values. But, the first button is causing problems, I think because there are UILayoutGuide objects that also have tag 0.
This solution was working but I've just upgraded to Xcode Version 8.0 (8A218a) and converted to swift 3.
I added the following code to the viewDidLoad function of the view controller:
// Get the subviews of the view
var subviews = view.subviews
// Return if there are no subviews
if subviews.count == 0 {
return
}
for subview : AnyObject in subviews{
// Do what you want to do with the subview
print("\(subview.tag) - \(subview)")
}
This produces the following log:
Optional(200) - UIImageView: 0x7ff3e240f3b0; frame = (-4 0; 383 667); autoresize = RM+BM; userInteractionEnabled = NO; tag = 200; layer =
Optional(200) - UIStackView: 0x7ff3e240f590; frame = (7 103; 360 360); opaque = NO; autoresize = RM+BM; tag = 200; layer = CATransformLayer: 0x6100002316a0
Optional(200) - UIImageView: 0x7ff3e24111b0; frame = (0 47; 375 436); autoresize = RM+BM; userInteractionEnabled = NO; tag = 200; layer = CALayer: 0x6100002344e0
Optional(200) - UIToolbar: 0x7ff3e2637ff0; frame = (0 623; 375 44); opaque = NO; autoresize = RM+BM; tag = 200; layer = CALayer: 0x6000000343e0
Optional(200) - UIImageView: 0x7ff3e26015f0; frame = (63 228; 248 211); autoresize = RM+BM; userInteractionEnabled = NO; tag = 200; layer = CALayer: 0x600000034ea0
Optional(200) - UILabel: 0x7ff3e263e2e0; frame = (117 313; 141 41); text = 'Nice Work'; opaque = NO; autoresize = RM+BM; userInteractionEnabled = NO; tag = 200; layer = _UILabelLayer: 0x600000093060
Optional(200) - UIStackView: 0x7ff3e263e750; frame = (127 491; 120 120); opaque = NO; autoresize = RM+BM; tag = 200; layer = CATransformLayer: 0x600000035520
Optional(0) - _UILayoutGuide: 0x7ff3e263ee80; frame = (0 0; 0 0); hidden = YES; layer = CALayer: 0x600000035bc0
Optional(0) - _UILayoutGuide: 0x7ff3e263f030; frame = (0 0; 0 0); hidden = YES; layer = CALayer: 0x600000035c60
So the last 2 output lines are my suspected UILayoutGuide objects. I didn't code them and they are not objects in the hierarchy. How do I see them/get rid of them?

Answer 1

If you just want to prevent the loop from adding the _UILayoutGuide (which is of class UILayoutSupport), do this:
// Get the subviews of the view
var subviews = view.subviews
// Return if there are no subviews
if subviews.count == 0 {
return
}
for subview : AnyObject in subviews{
// Do what you want to do with the subview
print("\(subview.tag) - \(subview)")
// Check for whether is it a UILayout class or not
if(subview is UILayoutSupport){
//This section is executed when UILayoutGuide will come into play
print("Don't add it to the stack")
}else{
// Write your code in this section
}
}
you can also print your stack, check for UILayoutGuide in it and remove it.

Answer 2

Simple answer is that the UILayoutGuides don't have tags. When you print the subview.tag its showing tag = 0 when there is no tag. So the issue with button 0 is not related to the UILayoutGuide.
I didn't figure out what the issue was with the tag 0 button but recoded to avoid using tag 0. Not exactly fixed but the solution works.