问题描述
我有一个 NSOutlineView，第 1 项和第 2 项之间的间距大于所有其他项之间的间距。这些是组项目。大纲视图非常简单。下面是我的代码，下面是我所指问题的图像：
var sections: [SidebarSection] = [
SidebarSection(title: "Section 1",items: ["1","2","3","4","5"]),SidebarSection(title: "Section 2","2"]),SidebarSection(title: "Section 3",SidebarSection(title: "Section 4",SidebarSection(title: "Section 5","2"])]
private let outlineView: SidebarOutlineView = SidebarOutlineView()
extension SidebarViewController: NSOutlineViewDataSource {
func outlineView(_ outlineView: NSOutlineView,isItemExpandable item: Any) -> Bool {
return item is SidebarSection
}
func outlineView(_ outlineView: NSOutlineView,child index: Int,ofItem item: Any?) -> Any {
if let section = item as? SidebarSection {
return section.items[index]
}
return sections[index]
}
func outlineView(_ outlineView: NSOutlineView,numberOfChildrenOfItem item: Any?) -> Int {
if let section = item as? SidebarSection {
return section.items.count
}
return sections.count
}
}
extension SidebarViewController: NSOutlineViewDelegate {
func outlineView(_ outlineView: NSOutlineView,heightOfRowByItem item: Any) -> CGFloat {
return 30
}
func outlineView(_ outlineView: NSOutlineView,isGroupItem item: Any) -> Bool {
return item is SidebarSection
}
func outlineView(_ outlineView: NSOutlineView,viewFor tableColumn: NSTableColumn?,item: Any) -> NSView? {
let view = outlineView.makeView(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "SidebarPlaylistCell"),owner: self) as! SidebarPlaylistCell
view.wantsLayer = true
view.textLabel.stringValue = (item as? SidebarSection)?.title ?? ""
view.imgView.wantsLayer = true
view.imgView.layer?.backgroundColor = NSColor.red.cgColor
return view
}
}
extension SidebarViewController {
func layout() {
scrollView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(scrollView)
scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
scrollView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
scrollView.documentView = outlineView
outlineView.headerView = nil
outlineView.delegate = self
outlineView.dataSource = self
outlineView.intercellSpacing = NSSize(width: 0,height: 0)
scrollView.hasverticalScroller = true
scrollView.hasHorizontalScroller = false
scrollView.wantsLayer = true
view.layer?.backgroundColor = NSColor.blue.cgColor
}
}
final class SidebarOutlineView: NSOutlineView {
override init(frame frameRect: NSRect) {
super.init(frame: frameRect)
let column: NSTableColumn = NSTableColumn(identifier: NSUserInterfaceItemIdentifier("col1"))
column.isEditable = false
column.minWidth = 0
addTableColumn(column)
outlineTableColumn = column
register(NSNib(nibNamed: "SidebarPlaylistCell",bundle: nil),forIdentifier: NSUserInterfaceItemIdentifier(rawValue: "SidebarPlaylistCell"))
selectionHighlightStyle = .sourceList
indentationPerLevel = 6.0
}
required init?(coder: NSCoder) {
super.init(coder: coder)
}
}
解决方法
此行为可以由布尔标志 floatsGroupRows 控制，该标志默认设置为 true。所以通过添加：
outlineView.floatsGroupRows = false
你得到了想要的行为。
文档可以在这里找到： https://developer.apple.com/documentation/appkit/nstableview/1528624-floatsgrouprows?language=swift
一个布尔值，指示表格视图是否将分组的行绘制成浮动的。
快速测试
floatGroupRows 的含义
floatsGroupRows 的效果可以在动画图形中更好的看到。在滚动操作期间，当前 GroupItem 保持浮动在顶部：
