Big Sur 大纲视图可扩展项目损坏

Question

我已经启动了一个新的 macOS 项目（目前在 Big Sur beta 3 上），NSOutlineView 节点似乎已损坏。不知道这是我还是操作系统。

Here's a sample project 证明了这个问题。还有一张图……

如您所见，单元格与扩展人字形重叠。单击任一 V 形将第一行恢复为正确的布局，但不是第二行。此外，永远不会调用自动保存方法 persistentObjectForItem 和 itemForPersistentObject。

测试项目非常简单——我所做的只是将视图库中的SourceView 组件添加到默认应用项目中，并将委托/数据源连接到视图控制器。还检查了 IB 中的 Autosave Expanded Items 并在 Autosave 字段中输入名称。这是整个控制器代码：

class ViewController: NSViewController {
    @IBOutlet var outlineView: NSOutlineView?

    let data = [Node("First item", 1), Node("Second item", 2)]
}

extension ViewController: NSOutlineViewDataSource {
    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        data[index]
    }
    
    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        true
    }
    
    func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
        item == nil ? data.count : 0
    }
    
    func outlineView(_ outlineView: NSOutlineView, objectValueFor tableColumn: NSTableColumn?, byItem item: Any?) -> Any? {
        item
    }
    
    func outlineView(_ outlineView: NSOutlineView, persistentObjectForItem item: Any?) -> Any? {
        (item as? Node)?.id
    }
    
    func outlineView(_ outlineView: NSOutlineView, itemForPersistentObject object: Any) -> Any? {
        guard let id = object as? Int else { return nil }
        return data.first { $0.id == id }
    }
}


extension ViewController: NSOutlineViewDelegate {
    func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
        guard let node = item as? Node else {
            preconditionFailure("Invalid data item \(item)")
        }
        let view = outlineView.makeView(withIdentifier: nodeCellIdentifier, owner: self) as? NSTableCellView
        view?.textField?.stringValue = node.name
        view?.imageView?.image = NSImage(systemSymbolName: node.icon, accessibilityDescription: nil)
        return view
    }
}


final class Node {
    let id: Int
    let name: String
    let icon: String
    
    init(_ name: String, _ id: Int, _ icon: String = "folder") {
        self.id = id
        self.name = name
        self.icon = icon
    }
}

private let nodeCellIdentifier = NSUserInterfaceItemIdentifier("DataCell")

有没有 Mac 开发人员可以提供帮助？

Answer 1

来源列表

什么是源列表？它是NSOutlineView（它是 NSTableView) 有一个特殊的 治疗。 Finder 截图：

要创建源列表，您所要做的就是设置 selectionHighlightStyle 属性 .sourceList。文档说：

NSTableView 的源列表样式。在 10.5 上，浅蓝色渐变用于突出显示选定的行。

它到底是做什么的？ 在 Xcode 中跳转到定义并读取 cmets（未包含在文档中）：

NSTableView 的源列表样式。在 10.10 及更高版本中，模糊选择用于突出显示行。在此之前，使用了浅蓝色渐变。注意：具有 drawsBackground 属性的单元格应将其设置为 NO。否则，它们将覆盖 NSTableView 所做的突出显示。设置此样式会产生将背景颜色设置为“源列表”背景颜色的副作用。此外，在 NSOutlineView 中，更改了以下属性以获得标准的“源列表”外观：indentationPerLevel、rowHeight 和 intercellSpacing。调用 setSelectionHighlightStyle: 后，可以根据需要更改任何其他属性。在 10.11 中，如果背景颜色已从“源列表”背景颜色更改为其他颜色，则表格将不再将所选内容绘制为源列表模糊样式，而是进行正常的蓝色突出显示。

由于您使用的是 Big Sur，请注意 SelectionHighlightStyle.sourceList 已弃用。 应该使用style &effectiveStyle.

示例项目

Xcode：

• 新项目
  • macOS 和应用程序（Storyboard 和 AppKit 应用程序委托和 Swift）
• Main.storyboard
  • 添加源列表控件
    • 定位和修复约束
    • 将委托和数据源设置为 ViewController
    • 启用自动保存展开的项目
    • 将自动保存设置为您想要的任何内容（我有 FinderLikeSidebar 那里）
      • 明智选择，因为展开状态保存在用户默认值中 在NSOutlineView Items FinderLikeSidebar 键下
    • 创建@IBOutlet var outlineView: NSOutlineView!
  • 添加另一个文本表格单元格视图（无图像）
    • 将标识符设置为GroupCell
• ViewController.swift
  • 下面的注释代码

截图

如您所见，它几乎就像 Finder 一样 - 第二级仍然是缩进的。原因 这是因为 Documents 节点是可扩展的（有子节点）。我在这里有它们来演示自动保存。

如果您想将所有 2 级节点移至左侧，只需将其移除即可。

ViewController.swift 代码

没什么好说的，除了 - 阅读 cmets :)

import Cocoa

// Sample Node class covering groups & regular items
class Node {
    let id: Int
    let title: String
    let symbolName: String?
    let children: [Node]
    let isGroup: Bool
    
    init(id: Int, title: String, symbolName: String? = nil, children: [Node] = [], isGroup: Bool = false) {
        self.id = id
        self.title = title
        self.symbolName = symbolName
        self.children = children
        self.isGroup = isGroup
    }
    
    convenience init(groupId: Int, title: String, children: [Node]) {
        self.init(id: groupId, title: title, children: children, isGroup: true)
    }
}

extension Node {
    var cellIdentifier: NSUserInterfaceItemIdentifier {
        // These must match identifiers in Main.storyboard
        NSUserInterfaceItemIdentifier(rawValue: isGroup ? "GroupCell" : "DataCell")
    }
}

extension Array where Self.Element == Node {
    // Search for a node (recursively) until a matching element is found
    func firstNode(where predicate: (Element) throws -> Bool) rethrows -> Element? {
        for element in self {
            if try predicate(element) {
                return element
            }
            if let matched = try element.children.firstNode(where: predicate) {
                return matched
            }
        }
        return nil
    }
}

class ViewController: NSViewController, NSOutlineViewDelegate, NSOutlineViewDataSource {
    @IBOutlet var outlineView: NSOutlineView!
    
    let data = [
        Node(groupId: 1, title: "Favorites", children: [
            Node(id: 11, title: "AirDrop", symbolName: "wifi"),
            Node(id: 12, title: "Recents", symbolName: "clock"),
            Node(id: 13, title: "Applications", symbolName: "hammer")
        ]),
        Node(groupId: 2, title: "iCloud", children: [
            Node(id: 21, title: "iCloud Drive", symbolName: "icloud"),
            Node(id: 22, title: "Documents", symbolName: "doc", children: [
                Node(id: 221, title: "Work", symbolName: "folder"),
                Node(id: 221, title: "Personal", symbolName: "folder.badge.person.crop"),
            ])
        ]),
    ]
    
    override func viewWillAppear() {
        super.viewWillAppear()
        
        // Expanded items are saved in the UserDefaults under the key:
        //
        // "NSOutlineView Items \(autosaveName)"
        //
        // By default, this value is not present. When you expand some nodes,
        // an array with persistent objects is saved. When you collapse all nodes,
        // the array is removed from the user defaults (not an empty array,
        // but back to nil = removed).
        //
        // IOW there's no way to check if user already saw this source list,
        // modified expansion state, etc. We will use custom key for this
        // purpose, so we can expand group nodes (top level) when the source
        // list is displayed for the first time.
        //
        // Next time, we wont expand anything and will honor autosaved expanded
        // items.
        if UserDefaults.standard.object(forKey: "FinderLikeSidebarAppeared") == nil {
            data.forEach {
                outlineView.expandItem($0)
            }
            UserDefaults.standard.set(true, forKey: "FinderLikeSidebarAppeared")
        }
    }
    
    // Number of children or groups (item == nil)
    func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
        item == nil ? data.count : (item as! Node).children.count
    }
    
    // Child of a node or group (item == nil)
    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        item == nil ? data[index] : (item as! Node).children[index]
    }
    
    // View for our node
    func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
        guard let node = item as? Node,
              let cell = outlineView.makeView(withIdentifier: node.cellIdentifier, owner: self) as? NSTableCellView else {
            return nil
        }
        
        cell.textField?.stringValue = node.title
        
        if !node.isGroup {
            cell.imageView?.image = NSImage(systemSymbolName: node.symbolName ?? "folder", accessibilityDescription: nil)
        }
        
        return cell
    }

    // Mark top level items as group items
    func outlineView(_ outlineView: NSOutlineView, isGroupItem item: Any) -> Bool {
        (item as! Node).isGroup
    }
    
    // Every node is expandable if it has children
    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        !(item as! Node).children.isEmpty
    }
    
    // Top level items (group items) are not selectable
    func outlineView(_ outlineView: NSOutlineView, shouldSelectItem item: Any) -> Bool {
        !(item as! Node).isGroup
    }
    
    // Object to save in the user defaults (NSOutlineView Items FinderLikeSidebar)
    func outlineView(_ outlineView: NSOutlineView, persistentObjectForItem item: Any?) -> Any? {
        (item as! Node).id
    }
    
    // Find an item from the saved object (NSOutlineView Items FinderLikeSidebar)
    func outlineView(_ outlineView: NSOutlineView, itemForPersistentObject object: Any) -> Any? {
        guard let id = object as? Int else { return nil }
        return data.firstNode { $0.id == id }
    }
}