Swift 4/Xcode 10 错误消息 : Illegal NSOutlineView data source

Question

***** 适合我的解决方案 ******

退出并重新启动 Xcode 修复了该问题

我在我的项目中使用 Xcode 10 和 swift 4。

如果在我的项目中自定义 View ，我正在使用 IB 创建自己的 View Controller 以将它们集成。

在其中一个 View Controller 上，我使用 NSOutlineView 来显示网络设备列表。

    public class applianceListPickerViewController: NSViewController, NSOutlineViewDelegate, NSOutlineViewDataSource {




@IBOutlet weak var applianceTreeView: NSOutlineView!
private var listOfAppliances = [appliance]()

override public func viewDidLoad() {
    super.viewDidLoad()
    // Do view setup here.

        self.applianceTreeView.dataSource = self
        self.applianceTreeView.delegate = self
        self.readRouterListFromFile(fileName: "lab_list")
        self.applianceTreeView.reloadData()
}

func readRouterListFromFile(fileName: String) -> Any?
{
    var listOfRouters = [BSDRouters]()
    if let path = Bundle.main.path(forResource: fileName, ofType: "json") {
        do {
            let fileUrl = URL(fileURLWithPath: path)
            // Getting data from JSON file using the file URL

            let data = try Data(contentsOf: fileUrl, options: .mappedIfSafe)
            listOfRouters = try JSONDecoder().decode([BSDRouters].self, from: data)

        } catch {
            // Handle error here
            print ("Not a valid Router list \(error)")
            return nil
        }
    }
    else{
        return nil
    }
    for currentRouter in listOfRouters {
        let anAppliance = appliance.init(withName: currentRouter.name)
        self.listOfAppliances.append(anAppliance    )
    }
    return listOfRouters
}

// MARK: - Data Source functions


// This one returns the appliances count if item is an appliance and pipe counts if its a pipe

private func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
    if let currentItem = item as? appliance {
        return currentItem.listOfipes.count
    }
    return listOfAppliances.count

}


private func outlineView(_ outlineView: NSOutlineView, objectValueFor tableColumn: NSTableColumn?, byItem item: Any?) -> Any?{
    print("Don't know why I have to define this one but its in the error message so I declare it")
    return nil
}

// This one returns an appliance object if item is an appliance and a pipe object  if its a pipe

private func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
    if let currentItem = item as? appliance {
        return currentItem.listOfipes[index]
    }

    return listOfAppliances[index]
}

private func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
    if let currentItem = item as? appliance {
        return currentItem.listOfipes.count > 0
    }
    return false
}

// MARK: - Delegates functions functions


private func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
    var view: NSTableCellView?
    if let currentItem = item as? appliance {
        view = outlineView.makeView(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "routerCell"), owner: self) as? NSTableCellView
        if let textField = view?.textField {
            textField.stringValue = currentItem.name
            textField.sizeToFit()
        }
    }
    return view
}}

我在调试部分收到以下错误消息:

Illegal NSOutlineView data source (). Must implement outlineView:numberOfChildrenOfItem:, outlineView:isItemExpandable:, outlineView:child:ofItem: and outlineView:objectValueForTableColumn:byItem:

这是不幸的，因为我已经定义了方法!

在文档中阅读它说可选方法 outlineView(_ outlineView: NSOutlineView, objectValueFor tableColumn: NSTableColumn?, byItem item: Any?) -> Any?当不使用我手动设置数据源和委托(delegate)时执行的 Cocoa 绑定(bind)时，这是强制性的。

我也一直在看这个: Error: Illegal NSOutlineView data source但它不包含任何解决我的问题的线索。

在 IB 上，我已将 outlet applianceTreeView 链接到我的 xib 的 OutlineView。

我尝试在 viewdidload 之后手动设置 applianceTreeView 的委托(delegate)和数据源，因为 nsoutlineview 似乎不符合委托(delegate)和数据源的协议(protocol)，但没有成功仍然收到相同的错误消息。

编辑:

数据源和委托(delegate)分配可能有问题，因为我可以看到数据源和委托(delegate)不是指向 View Controller (自身 0x00006000000e3300)，而是指向大纲 View (大纲 View 0x0000000101603e40)，如下图所示:

Answer 1

替换 private与 public

// This one returns the appliances count if item is an appliance and pipe counts if its a pipe

public func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
    if let currentItem = item as? appliance {
        return currentItem.listOfipes.count
    }
    return listOfAppliances.count

}


public func outlineView(_ outlineView: NSOutlineView, objectValueFor tableColumn: NSTableColumn?, byItem item: Any?) -> Any?{
    print("Don't know why I have to define this one but its in the error message so I declare it")
    return nil
}