将 xib 文件中的视图添加到 UITableViewCell 添加约束

Question

我创建了一个带有自定义视图的 xib 文件，我想在 UITableViewCell.

中显示

问题是：在 xib 文件中，我将 UIView 的宽度设置为 600（size 是 Freeform），但我想使用约束以便获得每个设备的正确宽度。

我在 UITableViewCell 和 addSubview() 中添加了这个视图，所以我认为这个视图必须约束到单元格的视图，对吗？我该怎么做？

我添加一些代码：

我的自定义 UIView 与 xib 文件相关：

class DownloadView: UIView, NSURLSessionDownloadDelegate{

///utilizzata per mostrare il nome del file in download
@IBOutlet var nomeFileInDownloadLabel: UILabel!

///utilizzata per mostrare la percentuale di download completato
@IBOutlet var quantitaScaricataLabel: UILabel!

///utilizzata per mostrare il download
@IBOutlet var progressView: UIProgressView!

var view : UIView!

private var downloadTask: NSURLSessionDownloadTask?

//Initialization
override init(frame: CGRect) {
    super.init(frame: frame)
    xibSetup()
}

required init(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)!
}


//I setup the xib from here
func xibSetup() {
    view = loadViewFromNib()

    //if I set the following one the view is a square
    //view.frame = bounds

    // Make the view stretch with containing view
    view.autoresizingMask = [UIViewAutoresizing.FlexibleWidth, UIViewAutoresizing.FlexibleHeight]
    self.addSubview(view)
}

//I load the xib file
func loadViewFromNib() -> UIView {

    let bundle = NSBundle(forClass: self.dynamicType)
    let nib = UINib(nibName: "View", bundle: bundle)
    let view = nib.instantiateWithOwner(self, options: nil)[0] as! UIView
    return view
}
//some code for other task 
...
}

在我的UITableView方法中tableView(tableView:cellForRowAtIndexPath)我添加了视图：

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("DownloadRootTVC_IDcell", forIndexPath: indexPath) as! DownloadTVCell

    //I get my custom view from an array
    let myView = self.listOfViewsDownlaod[indexPath.row]

    //I add the view to the cell
    cell.addSubview(myView)


    return cell
}

在最后一种方法中，我认为我必须设置约束以适应 UITableViewCell 中的自定义视图，使其适应设备宽度。

编辑：

因为我想使子视图的宽度和高度适应我这样写的单元格：

    let topConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 8)
    cell.addConstraint(topConstraint)

    let bottomConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 8)
    cell.addConstraint(bottomConstraint)

    let leftConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.Left, multiplier: 1, constant: 20)
    cell.addConstraint(leftConstraint)

    let rightConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.TrailingMargin, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.TrailingMargin, multiplier: 1, constant: 20)
    cell.addConstraint(rightConstraint)

唯一不起作用的是右边那个，视图在屏幕上继续。我还尝试使用 NSLayoutAttribute.Right 或 NSLayoutAttribute.RighMargin 或将常量设置为负值，但不起作用。

Answer 1

当您将 xib 视图添加为子视图时，它的父视图没有任何限制。您应该以编程方式创建它们。 There is 一个很好的例子。例如，如果你想把你的视图放在父视图的中心并且大小相同，你可以写下：

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

  let cell = tableView.dequeueReusableCellWithIdentifier("cell")!
  let myView = UIView()
  myView.backgroundColor = UIColor.redColor()
  myView.translatesAutoresizingMaskIntoConstraints = false
  cell.addSubview(myView)
  let horizontalConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
  cell.addConstraint(horizontalConstraint)

  let verticalConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
  cell.addConstraint(verticalConstraint)

  let widthConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.Width, multiplier: 1, constant: 0)
  cell.addConstraint(widthConstraint)

  let heightConstraint = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: cell, attribute: NSLayoutAttribute.Height, multiplier: 1, constant: 0)
  cell.addConstraint(heightConstraint)
  return cell
}

它看起来像这样（蓝色 - tableView，红色 - myView）：

Answer 2

终于找到问题了：

问题出在xibSetup()方法中，因为我加载了xib但没有设置约束！所以我的新方法是：

func xibSetup() {
    let myView = loadViewFromNib()

    myView.translatesAutoresizingMaskIntoConstraints = false

    self.addSubview(myView)

    let leading = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Leading, relatedBy: NSLayoutRelation.Equal, toItem: myView.superview, attribute: NSLayoutAttribute.Leading, multiplier: 1, constant: 0)
    self.addConstraint(leading)

    let bottom = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: myView.superview, attribute: NSLayoutAttribute.Bottom, multiplier: 1, constant: 0)
    self.addConstraint(bottom)

    let trailing = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Trailing, relatedBy: NSLayoutRelation.Equal, toItem: myView.superview, attribute: NSLayoutAttribute.Trailing, multiplier: 1, constant: 0)
    self.addConstraint(trailing)

    let top = NSLayoutConstraint(item: myView, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: myView.superview, attribute: NSLayoutAttribute.Top, multiplier: 1, constant: 0)
    self.addConstraint(top)

}

这解决了我的问题。

将 xib 文件中的视图添加到 UITableViewCell 添加约束

Add a view from a xib file to a UITableViewCell adding constraints

constraints

uitableview

xib

swift