How to programmatically determine the height of UIStackView after a subview has been hidden swift

Question

I am using a UIStackView within a UIScrollView and I want to determine the height of the stack view so I can programmatically adjust the height of the scrollview to accomodate when subviews are hidden.

I am using

stackView.frame.height

to determine stack view height. This is called in viewDidLoad() but it is always the same height value from the storyboard no matter if subviews are hidden or not.

How do I determine height?

`viewDidLoad` is too soon. Try `viewDidAppear`. – rmaddy Apr 04 '18 at 03:43 — rmaddy, Apr 04 '18 at 03:43

score 23 · Accepted Answer · answered Apr 04 '18 at 02:23

23

After making layout changes to any view, it has to recalculate it's frame after the function is completed. To get the updated frame right away, call:

stackView.layoutIfNeeded()

Example:

print(stackView.frame.height) // old height
subview1.isHidden = true
print(stackView.frame.height) // still old height
stackView.layoutIfNeeded()
print(stackView.frame.height) // new height

See the documentation for more details.

answered Apr 04 '18 at 02:23

tktsubota

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Thanks for the answer, I still receive the old height after .layoutIfNeeded(). – Khoury Apr 04 '18 at 03:03
@Khoury Have you tried removing the arranged subview altogether (not just hiding it) to see if that changes the height? – tktsubota Apr 04 '18 at 03:23
I changed it just now from hiding to .removeFromSuperview(), still no change in height? – Khoury Apr 04 '18 at 03:41
12

@Khoury you need to call `setNeedsLayout()` *before* `.layoutIfNeeded()`, then get the frame height. – paulvs Apr 04 '18 at 13:05
1

@Khoury instead of removeFromSuperview() try `stackview.removeArrangedSubview(subview1)` – froggomad Jul 11 '21 at 17:05

How to programmatically determine the height of UIStackView after a subview has been hidden swift

1 Answers1