UIStackView Hide View Animation

Question

In iOS 11 the behaviour of the hide animation within a UIStackView has changed, but I have been unable to find this documented anywhere.

iOS 10

iOS 11

The code in both is this:

UIView.animate(withDuration: DiscoverHeaderView.animationDuration,
                       delay: 0.0,
                       usingSpringWithDamping: 0.9,
                       initialSpringVelocity: 1,
                       options: [],
                       animations: {
                            clear.isHidden = hideClear
                            useMyLocation.isHidden = hideLocation
                        },
                       completion: nil)

How do I restore the previous behaviour on iOS 11?

Answer 1

Just had the same issue. The fix is adding stackView.layoutIfNeeded() inside the animation block. Where stackView is the container of the items you're wishing to hide.

UIView.animate(withDuration: DiscoverHeaderView.animationDuration,
                   delay: 0.0,
                   usingSpringWithDamping: 0.9,
                   initialSpringVelocity: 1,
                   options: [],
                   animations: {
                        clear.isHidden = hideClear
                        useMyLocation.isHidden = hideLocation
                        stackView.layoutIfNeeded()
                    },
                   completion: nil)

Not sure why this is suddenly an issue in iOS 11 but to be fair it has always been the recommended approach.