appkit-list.swift

import Cocoa

class FlippedView: NSView {
    override var isFlipped: Bool {
        return true
    }
}

private class Spacer: NSView {
    var height: CGFloat = 0
    
    init(height: CGFloat) {
        super.init(frame: .zero)
        self.height = height
        translatesAutoresizingMaskIntoConstraints = false
        heightAnchor.constraint(equalToConstant: height).isActive = true
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func add(on stackView: NSStackView) {
        let spacer = Spacer(height: self.height)
        stackView.addArrangedSubview(spacer)
    }
}

class ViewController: NSViewController {
    let items = Array(0..<50).map { String($0) }
    
    override func loadView() {
        self.view = NSView(frame: NSRect(x: 0, y: 0, width: 400, height: 300))
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let stackViewPadding: CGFloat = 10
        let spacer = Spacer(height: stackViewPadding)
        
        let scrollView = NSScrollView(frame: view.bounds)
        scrollView.hasVerticalScroller = true
        scrollView.autoresizingMask = [.width, .height]
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(scrollView)
        
        scrollView.drawsBackground = false
        
        let stackView = NSStackView()
        stackView.orientation = .vertical
        stackView.alignment = .leading
        stackView.spacing = 4
        stackView.translatesAutoresizingMaskIntoConstraints = false
        
        let flippedView = FlippedView()
        flippedView.addSubview(stackView)
        scrollView.documentView = flippedView
        
        spacer.add(on: stackView)
        
        for item in items {
            let textView = NSTextField(labelWithString: item)
            stackView.addArrangedSubview(textView)
        }
        
        spacer.add(on: stackView)
        
        let height = stackView.fittingSize.height
        scrollView.documentView?.frame.size = CGSize(width: scrollView.contentSize.width, height: height)
        
        NSLayoutConstraint.activate([
            scrollView.topAnchor.constraint(equalTo: view.topAnchor),
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
        ])
        
        NSLayoutConstraint.activate([
            stackView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: stackViewPadding),
            stackView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: stackViewPadding),
        ])
    }
}