UIStackView 隐藏视图动画

Question

在 iOS 11 中，UIStackView 中隐藏动画的行为发生了变化，但我无法在任何地方找到此文档。

iOS 10

iOS 11

两者的代码都是这样的：

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

如何在 iOS 11 上恢复之前的行为？

Answer 1

刚刚遇到同样的问题。 修复是在动画块内添加stackView.layoutIfNeeded()。其中stackView 是您要隐藏的项目的容器。

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)

不知道为什么这在 iOS 11 中突然成为一个问题，但公平地说，它一直是推荐的方法。

Answer 2

已在接受答案的 cmets 中提到，但这是我的问题，它不在此处的任何答案中，所以：

确保从不在已经隐藏的视图上设置isHidden = true。这会弄乱堆栈视图。

Answer 3

Swift 4 扩展：

// MARK: - Show hide animations in StackViews

extension UIView {

func hideAnimated(in stackView: UIStackView) {
    if !self.isHidden {
        UIView.animate(
            withDuration: 0.35,
            delay: 0,
            usingSpringWithDamping: 0.9,
            initialSpringVelocity: 1,
            options: [],
            animations: {
                self.isHidden = true
                stackView.layoutIfNeeded()
            },
            completion: nil
        )
    }
}

func showAnimated(in stackView: UIStackView) {
    if self.isHidden {
        UIView.animate(
            withDuration: 0.35,
            delay: 0,
            usingSpringWithDamping: 0.9,
            initialSpringVelocity: 1,
            options: [],
            animations: {
                self.isHidden = false
                stackView.layoutIfNeeded()
            },
            completion: nil
        )
    }
}
}

Answer 4

我想分享这个功能，它有利于在UIStackView 中隐藏和显示许多视图，因为我之前使用的所有代码都无法顺利运行，因为需要从某些图层中移除动画：

extension UIStackView {
    public func make(viewsHidden: [UIView], viewsVisible: [UIView], animated: Bool) {
        let viewsHidden = viewsHidden.filter({ $0.superview === self })
        let viewsVisible = viewsVisible.filter({ $0.superview === self })

        let blockToSetVisibility: ([UIView], _ hidden: Bool) -> Void = { views, hidden in
            views.forEach({ $0.isHidden = hidden })
        }

        // need for smooth animation
        let blockToSetAlphaForSubviewsOf: ([UIView], _ alpha: CGFloat) -> Void = { views, alpha in
            views.forEach({ view in
                view.subviews.forEach({ $0.alpha = alpha })
            })
        }

        if !animated {
            blockToSetVisibility(viewsHidden, true)
            blockToSetVisibility(viewsVisible, false)
            blockToSetAlphaForSubviewsOf(viewsHidden, 1)
            blockToSetAlphaForSubviewsOf(viewsVisible, 1)
        } else {
            // update hidden values of all views
            // without that animation doesn't go
            let allViews = viewsHidden + viewsVisible
            self.layer.removeAllAnimations()
            allViews.forEach { view in
                let oldHiddenValue = view.isHidden
                view.layer.removeAllAnimations()
                view.layer.isHidden = oldHiddenValue
            }

            UIView.animate(withDuration: 0.3,
                           delay: 0.0,
                           usingSpringWithDamping: 0.9,
                           initialSpringVelocity: 1,
                           options: [],
                           animations: {

                            blockToSetAlphaForSubviewsOf(viewsVisible, 1)
                            blockToSetAlphaForSubviewsOf(viewsHidden, 0)

                            blockToSetVisibility(viewsHidden, true)
                            blockToSetVisibility(viewsVisible, false)
                            self.layoutIfNeeded()
            },
                           completion: nil)
        }
    }
}

Answer 5

希望这可以为其他人节省几个小时的挫败感。

动画隐藏和同时显示多个 UIStackView 子视图是一团糟。

在某些情况下，动画块中的 .isHidden 更改会正确显示，直到下一个动画，然后 .isHidden 被忽略。我为此找到的唯一可靠技巧是在动画块的完成部分重复 .isHidden 指令。

    let time = 0.3

    UIView.animate(withDuration: time, animations: {

        //shows
        self.googleSignInView.isHidden = false
        self.googleSignInView.alpha = 1
        self.registerView.isHidden = false
        self.registerView.alpha = 1

        //hides
        self.usernameView.isHidden = true
        self.usernameView.alpha = 0
        self.passwordView.isHidden = true
        self.passwordView.alpha = 0

        self.stackView.layoutIfNeeded()

    }) { (finished) in

        self.googleSignInView.isHidden = false
        self.registerView.isHidden = false
        self.usernameView.isHidden = true
        self.passwordView.isHidden = true
    }