Swift macOS Skill

Native macOS application development with AppKit, system integration, and distribution.

Prerequisites

• Xcode 15+ on macOS Sonoma+
• Apple Developer account (for distribution)
• Understanding of AppKit fundamentals

Parameters

parameters:
  distribution_method:
    type: string
    enum: [app_store, developer_id, none]
    default: developer_id
  sandbox_enabled:
    type: boolean
    default: true
  min_macos_version:
    type: string
    default: "13.0"
  app_type:
    type: string
    enum: [document_based, single_window, menu_bar, agent]
    default: single_window

Topics Covered

AppKit Components

Component	Purpose
NSWindow	Window management
NSViewController	View controller
NSView	Base view class
NSMenu	Menu bar and context menus
NSStatusItem	Menu bar icon
NSAlert	Dialog boxes

Window Types

Type	Use Case
NSWindow	Standard window
NSPanel	Utility/floating window
NSPopover	Attached popover
NSSavePanel/NSOpenPanel	File dialogs

Distribution Methods

Method	Requirements
Mac App Store	Sandbox, App Review
Developer ID	Notarization
Direct	None (Gatekeeper blocks)

Code Examples

Menu Bar Application

import AppKit
import SwiftUI

@main
struct MenuBarApp: App {
    @NSApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    var body: some Scene {
        Settings {
            SettingsView()
        }
    }
}

final class AppDelegate: NSObject, NSApplicationDelegate {
    private var statusItem: NSStatusItem!
    private var popover: NSPopover!

    func applicationDidFinishLaunching(_ notification: Notification) {
        setupStatusItem()
        setupPopover()

        // Hide dock icon for menu bar only app
        NSApp.setActivationPolicy(.accessory)
    }

    private func setupStatusItem() {
        statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.squareLength)

        if let button = statusItem.button {
            button.image = NSImage(systemSymbolName: "star.fill", accessibilityDescription: "App")
            button.action = #selector(togglePopover)
        }
    }

    private func setupPopover() {
        popover = NSPopover()
        popover.contentSize = NSSize(width: 300, height: 400)
        popover.behavior = .transient
        popover.contentViewController = NSHostingController(rootView: PopoverView())
    }

    @objc private func togglePopover() {
        guard let button = statusItem.button else { return }

        if popover.isShown {
            popover.performClose(nil)
        } else {
            popover.show(relativeTo: button.bounds, of: button, preferredEdge: .minY)
            popover.contentViewController?.view.window?.makeKey()
        }
    }
}

struct PopoverView: View {
    @Environment(\.openSettings) private var openSettings

    var body: some View {
        VStack(spacing: 16) {
            Text("Menu Bar App")
                .font(.headline)

            Button("Settings") {
                openSettings()
            }

            Button("Quit") {
                NSApp.terminate(nil)
            }
        }
        .padding()
    }
}

NSDocument-Based App

import AppKit

final class Document: NSDocument {
    var content: String = ""

    override class var autosavesInPlace: Bool { true }

    override func makeWindowControllers() {
        let contentVC = ContentViewController(document: self)
        let window = NSWindow(contentViewController: contentVC)
        window.setContentSize(NSSize(width: 800, height: 600))

        let windowController = NSWindowController(window: window)
        addWindowController(windowController)
    }

    override func data(ofType typeName: String) throws -> Data {
        guard let data = content.data(using: .utf8) else {
            throw NSError(domain: NSOSStatusErrorDomain, code: writErr)
        }
        return data
    }

    override func read(from data: Data, ofType typeName: String) throws {
        guard let content = String(data: data, encoding: .utf8) else {
            throw NSError(domain: NSOSStatusErrorDomain, code: readErr)
        }
        self.content = content
    }
}

final class ContentViewController: NSViewController {
    private let document: Document

    init(document: Document) {
        self.document = document
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) not implemented")
    }

    override func loadView() {
        let scrollView = NSScrollView()
        let textView = NSTextView()

        textView.isEditable = true
        textView.isRichText = false
        textView.font = .monospacedSystemFont(ofSize: 13, weight: .regular)
        textView.string = document.content

        scrollView.documentView = textView
        scrollView.hasVerticalScroller = true

        view = scrollView
    }
}

Sandboxing with Security-Scoped Bookmarks

final class SandboxedFileAccess {
    private static let bookmarksKey = "securityScopedBookmarks"

    static func requestAccess(to url: URL) throws -> URL {
        let bookmark = try url.bookmarkData(
            options: .withSecurityScope,
            includingResourceValuesForKeys: nil,
            relativeTo: nil
        )

        var bookmarks = UserDefaults.standard.dictionary(forKey: bookmarksKey) as? [String: Data] ?? [:]
        bookmarks[url.path] = bookmark
        UserDefaults.standard.set(bookmarks, forKey: bookmarksKey)

        return url
    }

    static func accessBookmarkedURL(_ path: String) throws -> URL {
        guard let bookmarks = UserDefaults.standard.dictionary(forKey: bookmarksKey) as? [String: Data],
              let bookmarkData = bookmarks[path] else {
            throw SandboxError.noBookmark
        }

        var isStale = false
        let url = try URL(
            resolvingBookmarkData: bookmarkData,
            options: .withSecurityScope,
            relativeTo: nil,
            bookmarkDataIsStale: &isStale
        )

        if isStale {
            _ = try requestAccess(to: url)
        }

        return url
    }

    static func withAccess<T>(to url: URL, perform: (URL) throws -> T) throws -> T {
        guard url.startAccessingSecurityScopedResource() else {
            throw SandboxError.accessDenied
        }
        defer { url.stopAccessingSecurityScopedResource() }
        return try perform(url)
    }
}

enum SandboxError: Error {
    case noBookmark
    case accessDenied
}

Notarization Script

#!/bin/bash
set -e

APP_PATH="$1"
DEVELOPER_ID="Developer ID Application: Your Name (TEAMID)"
KEYCHAIN_PROFILE="notary-profile"

echo "Signing..."
codesign --force --options runtime --sign "$DEVELOPER_ID" \
    --deep --strict "$APP_PATH"

echo "Creating ZIP..."
ditto -c -k --keepParent "$APP_PATH" "app.zip"

echo "Submitting for notarization..."
xcrun notarytool submit "app.zip" \
    --keychain-profile "$KEYCHAIN_PROFILE" \
    --wait

echo "Stapling..."
xcrun stapler staple "$APP_PATH"

echo "Verifying..."
spctl --assess --type execute --verbose=2 "$APP_PATH"

echo "Done!"
rm "app.zip"

Troubleshooting

Common Issues

Issue	Cause	Solution
"App is damaged"	Not notarized	Notarize before distribution
Sandbox violation	Missing entitlement	Add required entitlement
Window not appearing	Wrong activation policy	Check NSApp.activationPolicy
Menu not responding	Missing target/action	Verify menu item connections
Sparkle updates fail	Code signing issue	Add exception entitlement

Debug Tips

# Check code signing
codesign -dv --verbose=4 App.app

# Check entitlements
codesign -d --entitlements :- App.app

# Check notarization
spctl --assess --type execute App.app

# View sandbox violations
log show --predicate 'subsystem == "com.apple.sandbox"' --last 1h

Validation Rules

validation:
  - rule: hardened_runtime
    severity: error
    check: Enable hardened runtime for notarization
  - rule: sandbox_entitlements
    severity: warning
    check: Only request necessary sandbox entitlements
  - rule: code_signing
    severity: error
    check: Sign with Developer ID for distribution

Usage

Skill("swift-macos")

Related Skills

• swift-swiftui - SwiftUI on macOS
• swift-architecture - App architecture
• swift-testing - Testing macOS apps