A Checkbox Cell in NSTableView Column Header

CheckboxHeaderCell.swift

//
//  CheckboxHeaderCell.swift
//
//  Created by Rachel on 2021/4/26.
//  Original: https://stackoverflow.com/questions/11961869/checkbox-in-nstableview-column-header
//

import Cocoa

class CheckboxCell: NSButtonCell {
    var alternateState: NSControl.StateValue = .off {
        didSet {
            super.state = alternateState
        }
    }
    
    // Ignores the default behavior
    override var state: NSControl.StateValue {
        get { alternateState }
        set { }
    }
}

class CheckboxHeaderCell: NSTableHeaderCell {
    private lazy var innerCell: CheckboxCell = {
        let cell = CheckboxCell()
        cell.title = ""
        cell.setButtonType(.switch)
        cell.type = .nullCellType
        cell.isBordered = false
        cell.imagePosition = .imageOnly
        cell.alignment = .center
        cell.objectValue = NSNumber(booleanLiteral: false)
        cell.controlSize = .regular
        cell.font = NSFont.systemFont(ofSize: NSFont.systemFontSize(for: .small))
        cell.allowsMixedState = true
        return cell
    }()
    
    // Hide the default "Field" text
    override var textColor: NSColor? {
        get { .clear }
        set { }
    }
    
    override var title: String {
        get { innerCell.title }
        set { innerCell.title = newValue }
    }
    
    override var image: NSImage? {
        get { innerCell.image }
        set { innerCell.image = newValue }
    }
    
    // We should not override `state` of this class.
    // Instead, a property named `alternateState` is better for accessing its innerCell's state.
    var alternateState: NSControl.StateValue {
        get { innerCell.alternateState }
        set { innerCell.alternateState = newValue }
    }
    
    func toggleAlternateState() -> NSControl.StateValue {
        innerCell.alternateState = (alternateState != .on ? .on : .off)
        return innerCell.alternateState
    }
    
    // Override the original -drawWithFrame:inView: will also remove the background or border of the original cell, which is not recommended.
    override func drawInterior(withFrame cellFrame: NSRect, in controlView: NSView) {
        super.drawInterior(withFrame: cellFrame, in: controlView)
        let centeredRect = CGRect(
            x: cellFrame.midX - innerCell.cellSize.width / 2.0,
            y: cellFrame.midY - innerCell.cellSize.height / 2.0,
            width: innerCell.cellSize.width,
            height: innerCell.cellSize.height
        )
        innerCell.draw(withFrame: centeredRect, in: controlView)
    }
}

Usage

Setup

@IBOutlet weak var tableColumnChecked: NSTableColumn!
override func viewDidLoad() {
    super.viewDidLoad()
    tableColumnChecked.headerCell = CheckboxHeaderCell()
}

Send Action

private extension NSUserInterfaceItemIdentifier {
    // the checkbox column
    static let columnChecked = NSUserInterfaceItemIdentifier("col-checked")
}

func setupAlternateState(_ state: NSControl.StateValue) {
    // modify data source
}

func tableView(_ tableView: NSTableView, didClick tableColumn: NSTableColumn) {
    if tableColumn == tableColumnChecked {
        if let headerCell = tableColumn.headerCell as? CheckboxHeaderCell {
            // apply state changes to its data source
            setupAlternateState(headerCell.toggleAlternateState())
            // reload display, select or deselect all checkboxes
            tableView.reloadData(
                forRowIndexes: IndexSet(integersIn: 0..<tableView.numberOfRows),
                columnIndexes: IndexSet(integer: tableView.column(withIdentifier: .columnChecked))
            )
        }
    }
}

Re-draw

if let headerCell = tableColumnChecked.headerCell as? CheckboxHeaderCell {
    headerCell.alternateState = .on  // .off or .mixed
    tableView.headerView?.needsDisplay = true
}

This is crashing for me

Copy and pasted the code; have a tableVIew with two columns. XCode 14.2 macOS 12.6.3

Crashes here

override var image: NSImage? {
   get { innerCell.image }   //<- Crash with Thread 1: EXC_BAD_ACCESS (code=1, address=0x20)
   set { innerCell.image = newValue }
}

Any suggestions?