斯威夫特: NSCollectionViewItem没有出现在NSViewController中

Question

我正在用NSCollectionView开发一个应用程序，NSCollectionView的行为是如此的奇怪，有时它会使单元格可见，有时则不会。

@IBOutlet weak var resourceCollectionView: NSCollectionView!

private func prepareCollectionView() {
    let flowLayoutForEvent = NSCollectionViewFlowLayout()
flowLayoutForEvent.scrollDirection = .vertical
flowLayoutForEvent.minimumInteritemSpacing = 100
       
resourceCollectionView.collectionViewLayout = flowLayoutForEvent
       
resourceCollectionView.delegate = self
resourceCollectionView.dataSource = self
resourceCollectionView.isSelectable = true
       
       
resourceCollectionView.backgroundColors = [.clear]
resourceCollectionView.register(SimpleCell.self, forItemWithIdentifier: NSUserInterfaceItemIdentifier(rawValue: "SimpleCell"))
}

然后应用该函数

public override func viewDidLoad() {
        super.viewDidLoad()

         prepareCollectionView()
    }

以下是NSCollectionView的扩展函数

extension DashboardController : NSCollectionViewDelegateFlowLayout, NSCollectionViewDataSource {
  
  // 1
  public func numberOfSections(in collectionView: NSCollectionView) -> Int {
    return 1
  }
  
  // 2
  public func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {
    return 10
  }
  
  // 3
  public func collectionView(_ itemForRepresentedObjectAtcollectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {    
    let cell = resourceCollectionView.makeItem(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "SimpleCell"), for: indexPath) as! SimpleCell

   
     return cell

  }
    
    public func collectionView(_ collectionView: NSCollectionView, didSelectItemsAt indexPaths: Set<IndexPath>) {
        print("selected item > ",  indexPaths )
    }
    
    
    public func collectionView(_ collectionView: NSCollectionView, layout collectionViewLayout: NSCollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> NSSize {
        return NSSize(width: 10 , height:10)
    }
    
  
}

下面是以编程方式为NSCollectionView编写的单元格

class SimpleCell: NSCollectionViewItem {

private var containerView: NSView!

private var containBox: NSBox = {
    var box = NSBox()
    box.boxType = .custom
    box.fillColor = NSColor.purple
    box.translatesAutoresizingMaskIntoConstraints = false
    return box
}()


override func loadView() {
    containerView = NSView()
    self.view = containerView
    containerView.bounds = self.view.bounds


    containerView.addSubview(containBox)
    containBox.topAnchor.constraint(equalTo: containerView.topAnchor).isActive = true
    containBox.leftAnchor.constraint(equalTo: containerView.leftAnchor).isActive = true
    containBox.bottomAnchor.constraint(equalTo: containerView.bottomAnchor).isActive = true
    containBox.rightAnchor.constraint(equalTo: containerView.rightAnchor).isActive = true
}


}

resourceCollectionView没有显示单元格，而且有一种奇怪的行为，比如当我添加一行resourceCollectionView.reloadData()时，它会显示出来，然后自动隐藏所有的单元格。

在这种情况下，遗漏了哪些要点？

提前感谢

编辑：

我已经解决了我的问题，当我展示我使用的另一个NSViewController时

self.view = anotherViewController.view 

然后不触发NSCollectionView的任何功能。

然后我把它改成

self.view.window?.contentViewController = anotherViewController

然后起作用了。

Answer 1

我已经解决了我的问题，当我展示我使用的另一个NSViewController时

self.view = anotherViewController.view 

然后不触发NSCollectionView的任何功能。

然后我把它改成

self.view.window?.contentViewController = anotherViewController

它解决了我的问题。