如何创建视图之间可变间距的 UIStackView？

Question

我有一个简单的水平 UIStackView，里面有几个 UIView。我的目标是在视图之间创建可变间距。我很清楚我可以使用 "spacing" 属性在子视图之间创建常量 space。但是我的目标是创建变量 space。请注意，如果可能的话，我想避免使用充当 spacers.

的不可见视图

我想到的最好办法是将我的 UIViews 包装在一个单独的 UIStackView 中，并使用 layoutMarginsRelativeArrangement = YES 来尊重我的内部堆栈的布局边距。我希望我可以对任何 UIView 做类似的事情，而不必求助于这种丑陋的解决方法。这是我的示例代码：

// Create stack view
UIStackView *stackView = [[UIStackView alloc] init];
stackView.translatesAutoresizingMaskIntoConstraints = NO;
stackView.axis = UILayoutConstraintAxisHorizontal;
stackView.alignment = UIStackViewAlignmentCenter;
stackView.layoutMarginsRelativeArrangement = YES;

// Create subview
UIView *view1 = [[UIView alloc] init];
view1.translatesAutoresizingMaskIntoConstraints = NO;
// ... Add Auto Layout constraints for height / width
// ...
// I was hoping the layoutMargins would be respected, but they are not
view1.layoutMargins = UIEdgeInsetsMake(0, 25, 0, 0);

// ... Create more subviews
// UIView view2 = [[UIView alloc] init];
// ...

// Stack the subviews
[stackView addArrangedSubview:view1];
[stackView addArrangedSubview:view2];

结果是一个堆栈，视图彼此相邻，间距为：

Answer 1

更新 iOS 11，具有自定义间距的 StackViews

Apple 在 iOS11 中添加了设置自定义间距的功能。您只需在每个排列的子视图之后指定间距即可。很遗憾，您之前无法指定间距。

stackView.setCustomSpacing(10.0, after: firstLabel)
stackView.setCustomSpacing(10.0, after: secondLabel)

仍然比使用您自己的视图要好得多。

iOS10 岁及以下

您可以简单地将透明视图添加到您的堆栈视图中并为其添加宽度限制。

（标签 - UIView - 标签 - UIView -Label）

并且如果您保留 distribution 进行填充，那么您可以在 UIView 上设置可变宽度约束。

但如果是这种情况，我会考虑在这种情况下使用堆栈视图是否合适。自动布局使得在视图之间设置可变宽度变得非常容易。

Answer 2

根据 Rob's 的回复，我创建了一个 UIStackView 扩展，可能会有帮助：

extension UIStackView {
  func addCustomSpacing(_ spacing: CGFloat, after arrangedSubview: UIView) {
    if #available(iOS 11.0, *) {
      self.setCustomSpacing(spacing, after: arrangedSubview)
    } else {
      let separatorView = UIView(frame: .zero)
      separatorView.translatesAutoresizingMaskIntoConstraints = false
      switch axis {
      case .horizontal:
        separatorView.widthAnchor.constraint(equalToConstant: spacing).isActive = true
      case .vertical:
        separatorView.heightAnchor.constraint(equalToConstant: spacing).isActive = true
      }
      if let index = self.arrangedSubviews.firstIndex(of: arrangedSubview) {
        insertArrangedSubview(separatorView, at: index + 1)
      }
    }
  }
}

您可以随意使用和修改它，例如，如果您想要“separatorView”引用，您可以 return UIView:

  func addCustomSpacing(_ spacing: CGFloat, after arrangedSubview: UIView) -> UIView?

Answer 3

SWIFT 4

按照 lilpit 的回答，这里是 UIStackView 的扩展，用于为您的 arrangedSubview 添加顶部和底部间距

extension UIStackView {
    func addCustomSpacing(top: CGFloat, bottom: CGFloat) {

        //If the stack view has just one arrangedView, we add a dummy one
        if self.arrangedSubviews.count == 1 {
            self.insertArrangedSubview(UIView(frame: .zero), at: 0)
        }

        //Getting the second last arrangedSubview and the current one
        let lastTwoArrangedSubviews = Array(self.arrangedSubviews.suffix(2))
        let arrSpacing: [CGFloat] = [top, bottom]

        //Looping through the two last arrangedSubview to add spacing in each of them
        for (index, anArrangedSubview) in lastTwoArrangedSubviews.enumerated() {

            //After iOS 11, the stackview has a native method
            if #available(iOS 11.0, *) {
                self.setCustomSpacing(arrSpacing[index], after: anArrangedSubview)
                //Before iOS 11 : Adding dummy separator UIViews
            } else {
                guard let arrangedSubviewIndex = arrangedSubviews.firstIndex(of: anArrangedSubview) else {
                    return
                }

                let separatorView = UIView(frame: .zero)
                separatorView.translatesAutoresizingMaskIntoConstraints = false

                //calculate spacing to keep a coherent spacing with the ios11 version
                let isBetweenExisitingViews = arrangedSubviewIndex != arrangedSubviews.count - 1
                let existingSpacing = isBetweenExisitingViews ? 2 * spacing : spacing
                let separatorSize = arrSpacing[index] - existingSpacing

                guard separatorSize > 0 else {
                    return
                }

                switch axis {
                case .horizontal:
                    separatorView.widthAnchor.constraint(equalToConstant: separatorSize).isActive = true
                case .vertical:
                    separatorView.heightAnchor.constraint(equalToConstant: separatorSize).isActive = true
                }

                insertArrangedSubview(separatorView, at: arrangedSubviewIndex + 1)
            }
        }
    }
}

然后你会像这样使用它：

//Creating label to add to the UIStackview
let label = UILabel(frame: .zero)

//Adding label to the UIStackview
stackView.addArrangedSubview(label)

//Create margin on top and bottom of the UILabel
stackView.addCustomSpacing(top: 40, bottom: 100)

Answer 4

为了支持 iOS 11.x 及更低版本，我像 Enrique 提到的那样扩展了 UIStackView，但是我修改了它以包括：

在 arrangedSubview
处理 space 已经存在且只需要更新的情况
删除添加的 space

extension UIStackView {

    func addSpacing(_ spacing: CGFloat, after arrangedSubview: UIView) {
        if #available(iOS 11.0, *) {
            setCustomSpacing(spacing, after: arrangedSubview)
        } else {

            let index = arrangedSubviews.firstIndex(of: arrangedSubview)

            if let index = index, arrangedSubviews.count > (index + 1), arrangedSubviews[index + 1].accessibilityIdentifier == "spacer" {

                arrangedSubviews[index + 1].updateConstraint(axis == .horizontal ? .width : .height, to: spacing)
            } else {
                let separatorView = UIView(frame: .zero)
                separatorView.accessibilityIdentifier = "spacer"
                separatorView.translatesAutoresizingMaskIntoConstraints = false

                switch axis {
                case .horizontal:
                    separatorView.widthAnchor.constraint(equalToConstant: spacing).isActive = true
                case .vertical:
                    separatorView.heightAnchor.constraint(equalToConstant: spacing).isActive = true
                @unknown default:
                    return
                }
                if let index = index {
                    insertArrangedSubview(separatorView, at: index + 1)
                }
            }
        }
    }

    func addSpacing(_ spacing: CGFloat, before arrangedSubview: UIView) {

        let index = arrangedSubviews.firstIndex(of: arrangedSubview)

        if let index = index, index > 0, arrangedSubviews[index - 1].accessibilityIdentifier == "spacer" {

            let previousSpacer = arrangedSubviews[index - 1]

            switch axis {
            case .horizontal:
                previousSpacer.updateConstraint(.width, to: spacing)
            case .vertical:
                previousSpacer.updateConstraint(.height, to: spacing)
            @unknown default: return // Incase NSLayoutConstraint.Axis is extended in future
            }
        } else {
            let separatorView = UIView(frame: .zero)
            separatorView.accessibilityIdentifier = "spacer"
            separatorView.translatesAutoresizingMaskIntoConstraints = false

            switch axis {
            case .horizontal:
                separatorView.widthAnchor.constraint(equalToConstant: spacing).isActive = true
            case .vertical:
                separatorView.heightAnchor.constraint(equalToConstant: spacing).isActive = true
            @unknown default:
                return
            }
            if let index = index {
                insertArrangedSubview(separatorView, at: max(index - 1, 0))
            }
        }

    }

    func removeSpacing(after arrangedSubview: UIView) {
        if #available(iOS 11.0, *) {
            setCustomSpacing(0, after: arrangedSubview)
        } else {
            if let index = arrangedSubviews.firstIndex(of: arrangedSubview), arrangedSubviews.count > (index + 1), arrangedSubviews[index + 1].accessibilityIdentifier == "spacer" {
                arrangedSubviews[index + 1].removeFromStack()
            }
        }
    }

    func removeSpacing(before arrangedSubview: UIView) {
        if let index = arrangedSubviews.firstIndex(of: arrangedSubview), index > 0, arrangedSubviews[index - 1].accessibilityIdentifier == "spacer" {
            arrangedSubviews[index - 1].removeFromStack()
        }
    }
}


extension UIView {
    func updateConstraint(_ attribute: NSLayoutConstraint.Attribute, to constant: CGFloat) {
        for constraint in constraints {
            if constraint.firstAttribute == attribute {
              constraint.constant = constant
            }
        }
    }

    func removeFromStack() {
        if let stack = superview as? UIStackView, stack.arrangedSubviews.contains(self) {
            stack.removeArrangedSubview(self)
            // Note: 1
            removeFromSuperview()
        }
    }
}

注意：1 - 根据文档：

To prevent the view from appearing on screen after calling the stack’s removeArrangedSubview: method, explicitly remove the view from the subviews array by calling the view’s removeFromSuperview() method, or set the view’s isHidden property to true.

Answer 5

实现类似于 CSS 边距和填充的类似行为。

边距

myStackView.directionalLayoutMargins = NSDirectionalEdgeInsets(top: top, 前导：左，下：下，尾随：右);

边距（创建包装视图并向包装添加填充）

    wrapper = UIStackView();
    wrapper!.frame = viewToAdd.frame;
    wrapper!.frame.size.height = wrapper!.frame.size.height + marginTop + marginBottom;
    wrapper!.frame.size.width = wrapper!.frame.size.width + marginLeft + marginRight;
    (wrapper! as! UIStackView).axis = .horizontal;
    (wrapper! as! UIStackView).alignment = .fill
    (wrapper! as! UIStackView).spacing = 0
    (wrapper! as! UIStackView).distribution = .fill
    wrapper!.translatesAutoresizingMaskIntoConstraints = false

    (wrapper! as! UIStackView).isLayoutMarginsRelativeArrangement = true;
    (wrapper! as! UIStackView).insetsLayoutMarginsFromSafeArea = false;
    wrapper!.directionalLayoutMargins = NSDirectionalEdgeInsets(top: marginTop, leading: marginLeft, bottom: marginBottom, trailing: marginRight);wrapper.addArrangedSubview(viewToAdd);

Answer 6

如果您不知道以前的视图，您可以创建自己的间距 UIView 并将其作为排列的子视图添加到您的堆栈视图中。

func spacing(value: CGFloat) -> UIView {
    let spacerView = UIView(frame: CGRect(x: 0, y: 0, width: 0, height: 0))
    spacerView.translatesAutoresizingMaskIntoConstraints = false
    spacerView.heightAnchor.constraint(equalToConstant: value).isActive = true
    return spacerView
}
stackView.addArrangedSubview(spacing(value: 16))

如何创建视图之间可变间距的 UIStackView？

How can I create UIStackView with variable spacing between views?

ios-autolayout

ios9

uistackview