xcode 使用 UIStackView 的动态 UITableView 行高？

Dynamic UITableView row height using UIStackView?

提问by memmons

Surprised this isn't working out of the box, as this seems to be an important use case for stack views. I have a UITableViewCellsubclass which adds a UIStackView to the contentView. I'm adding labels to the stack view in tableView(_cellForRowAtIndexPath:)and the tableview is set to use dynamic row heights, but it doesn't appear to work, at least in Xcode 7.3. I was also under the impression that hiding arranged subviews in a stack view was animatable, but that seems broken as well.

令人惊讶的是，这不是开箱即用的，因为这似乎是堆栈视图的一个重要用例。我有一个UITableViewCell将 UIStackView 添加到 contentView的子类。我正在将标签添加到堆栈视图中tableView(_cellForRowAtIndexPath:)，并且 tableview 设置为使用动态行高，但它似乎不起作用，至少在 Xcode 7.3 中。我还认为在堆栈视图中隐藏排列的子视图是可动画的，但这似乎也坏了。

Any ideas on how to get this working correctly?

关于如何使其正常工作的任何想法？

class StackCell : UITableViewCell {
    enum VisualFormat: String {
        case HorizontalStackViewFormat = "H:|[stackView]|"
        case VerticalStackViewFormat = "V:|[stackView(>=44)]|"
    }

    var hasSetupConstraints = false
    lazy var stackView : UIStackView! = {
        let stack = UIStackView()
        stack.axis = .Vertical
        stack.distribution = .FillProportionally
        stack.alignment = .Fill
        stack.spacing = 3.0
        stack.translatesAutoresizingMaskIntoConstraints = false
        return stack
    }()

    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        contentView.addSubview(stackView)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func updateConstraints() {
        if !hasSetupConstraints {
            hasSetupConstraints = true
            let viewsDictionary: [String:AnyObject] = ["stackView" : stackView]
            var newConstraints = [NSLayoutConstraint]()
            newConstraints += self.newConstraints(VisualFormat.HorizontalStackViewFormat.rawValue, viewsDictionary: viewsDictionary)
            newConstraints += self.newConstraints(VisualFormat.VerticalStackViewFormat.rawValue, viewsDictionary: viewsDictionary)
            addConstraints(newConstraints)
        }
        super.updateConstraints()
    }

    private func newConstraints(visualFormat: String, viewsDictionary: [String:AnyObject]) -> [NSLayoutConstraint] {
        return NSLayoutConstraint.constraintsWithVisualFormat(visualFormat, options: [], metrics: nil, views: viewsDictionary)
    }

class ViewController: UITableViewController {

    private let reuseIdentifier = "StackCell"
    private let cellClass = StackCell.self

    override func viewDidLoad() {
        super.viewDidLoad()
        configureTableView(self.tableView)
    }

    private func configureTableView(tableView: UITableView) {
        tableView.registerClass(cellClass, forCellReuseIdentifier: reuseIdentifier)
        tableView.separatorStyle = .SingleLine
        tableView.estimatedRowHeight = 88
        tableView.rowHeight = UITableViewAutomaticDimension
    }

    private func newLabel(title: String) -> UILabel {
        let label = UILabel()
        label.text = title
        return label
    }

    // MARK: - UITableView
    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 4
    }

    override func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 44.0
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 10
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier(reuseIdentifier, forIndexPath: indexPath) as! StackCell
        cell.stackView.arrangedSubviews.forEach({
import UIKit
class StackCell : UITableViewCell {
    enum VisualFormat: String {
        case HorizontalStackViewFormat = "H:|[stackView]|"
        case VerticalStackViewFormat = "V:|[stackView(>=44)]|"
    }

    var hasSetupConstraints = false
    lazy var stackView : UIStackView! = {
        let stack = UIStackView()
        stack.axis = UILayoutConstraintAxis.Vertical
        stack.distribution = .FillProportionally
        stack.alignment = .Fill
        stack.spacing = 3.0
        stack.translatesAutoresizingMaskIntoConstraints = false
        stack.setContentCompressionResistancePriority(UILayoutPriorityRequired, forAxis: .Vertical)
        return stack
    }()

    override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        contentView.addSubview(stackView)
        addStackConstraints()
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    private func addStackConstraints() {
        let viewsDictionary: [String:AnyObject] = ["stackView" : stackView]
        var newConstraints = [NSLayoutConstraint]()
        newConstraints += self.newConstraints(VisualFormat.HorizontalStackViewFormat.rawValue, viewsDictionary: viewsDictionary)
        newConstraints += self.newConstraints(VisualFormat.VerticalStackViewFormat.rawValue, viewsDictionary: viewsDictionary)
        contentView.addConstraints(newConstraints)
        super.updateConstraints()
    }

    private func newConstraints(visualFormat: String, viewsDictionary: [String:AnyObject]) -> [NSLayoutConstraint] {
        return NSLayoutConstraint.constraintsWithVisualFormat(visualFormat, options: [], metrics: nil, views: viewsDictionary)
    }
}
.removeFromSuperview()})
        cell.stackView.addArrangedSubview(newLabel("\(indexPath.section)-\(indexPath.row)"))
        cell.stackView.addArrangedSubview(newLabel("Second Label"))
        cell.stackView.addArrangedSubview(newLabel("Third Label"))
        cell.stackView.addArrangedSubview(newLabel("Fourth Label"))
        cell.stackView.addArrangedSubview(newLabel("Fifth Label"))
        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        let cell = tableView.cellForRowAtIndexPath(indexPath) as! StackCell
        for (idx, view) in cell.stackView.arrangedSubviews.enumerate() {
            if idx == 0 {
                continue
            }
            view.hidden = !view.hidden
        }
        UIView.animateWithDuration(0.3, animations: {
            cell.contentView.layoutIfNeeded()
            tableView.beginUpdates()
            tableView.endUpdates()

        })
    }
}

回答by memmons

It seems that for this to work the constraints need to be added in the init of the UITableViewCelland added to the contentViewinstead of cell's view.

似乎要使其工作，需要在 init 中添加约束UITableViewCell并将其添加到contentView而不是单元格的视图中。

The working code looks like this:

工作代码如下所示：

##代码##