UIStackView moves it's arranged subviews to top left when all subviews are hidden within an animation block

Question

If I try to animate the hiding all the subviews of a stackview, I can see them moving towards the top left corner. On showing, they are animated coming from top left to their proper space. If I hide only a subset of the arranged views, they are animated as expected.

My current workaround is to keep an invisible subview in the stack, but this is super wonky.

I am hiding via

UIView.animate(withDuration: 0.5) {                
    self.someStack.arrangedSubviews.forEach { $0.isHidden = !$0.isHidden 
}

Hello, I have the same problem, did you find a way to solve it? thanks — Sonia Casas, Nov 04 '16 at 08:01
Nothing completely satisfactory. I resorted to having an UIVIew wth height constrained to 0, that I never hide or remove. I set all my other views to hidden, when needed and it works well. — Морт, Nov 08 '16 at 10:20
Thanks! I was thinking about doing the same. It's te only way — Sonia Casas, Nov 08 '16 at 11:50

score 3 · Accepted Answer · answered Apr 27 '17 at 15:05

I faced a very similar problem and after a few hours of back and forth, I found that calling self.view.layoutIfNeeded() fixed the issue.

My hierarchy:

- UIView - UIStackView - UIStackView(1) - UIButton - UIButton - UIStackView(2) - UITextField - UIButton - UIActivityIndicatorView

The root UIView animates from the bottom when the keyboard appears based on a call to UITextField.becomeFirstResponder() in the (2)UIStackView. By default, every subview of (2)UIStackView is hidden. Based on a UISegmentedControl change, the app calls UITextField.becomeFirstResponder() and hides (1)UIStackView and shows (2)UIStackView. If I don't call self.view.layoutIfNeeded() after stackView.subviews.forEach { $0.isHidden = false } to show the subviews of (2)UIStackView I see them animating from the top left of the device.

I don't know if this might help you, but it might be a starting point to investigate.

score 2 · Answer 2 · answered Jul 26 '17 at 13:10

2

Try adding an additional empty view (width/height 0) into your stack view. This fixed the issue for me.

answered Jul 26 '17 at 13:10

JimmyB

326
3
12

This should be the accepted answer. Works like charm for me. – Vinayak Nov 16 '20 at 21:37

UIStackView moves it's arranged subviews to top left when all subviews are hidden within an animation block

2 Answers2