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Álvaro Ramírez

Álvaro Ramírez

02 August 2020 SwiftUI macOS desk clock


For time display, I've gone back and forth between an always-displayed macOS's menu bar to an auto-hide menu bar, and letting Emacs display the time. Neither felt great nor settled.

With some tweaks, Paul Hudson's How to use a timer with SwiftUI, led me to build a simple desk clock. Ok, let's not get fancy. It's really just an always-on-top floating window, showing a swiftUI label, but hey I like the minimalist feel ;)

Let's see if it sticks around or it gets in the way… Either way, here's standalone snippet. Run with swift deskclock.swift.

import Cocoa
import SwiftUI

let application = NSApplication.shared
let appDelegate = AppDelegate()
application.delegate = appDelegate
application.mainMenu = NSMenu.makeMenu()

struct ClockView: View {
  @State var time = "--:--"

  let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()

  var body: some View {
    GeometryReader { geometry in

      VStack {
          .onReceive(timer) { input in
            let formatter = DateFormatter()
            formatter.dateFormat = "HH:mm"
            time = formatter.string(from: input)
          .font(.system(size: 40))
      }.frame(width: geometry.size.width, height: geometry.size.height)
        .frame(maxWidth: .infinity, maxHeight: .infinity)

extension NSWindow {
  static func makeWindow() -> NSWindow {
    let window = NSWindow(
      contentRect: NSRect.makeDefault(),
      styleMask: [.closable, .miniaturizable, .resizable, .fullSizeContentView],
      backing: .buffered, defer: false)
    window.level = .floating
    window.collectionBehavior = [.canJoinAllSpaces, .stationary, .ignoresCycle, .fullScreenPrimary]
    window.isMovableByWindowBackground = true
    window.titleVisibility = .hidden
    window.backgroundColor = .clear
    return window

class AppDelegate: NSObject, NSApplicationDelegate {
  var window = NSWindow.makeWindow()
  var hostingView: NSView?

  func applicationDidFinishLaunching(_ notification: Notification) {
    hostingView = NSHostingView(rootView: ClockView())
    window.contentView = hostingView
    NSApp.activate(ignoringOtherApps: true)

extension NSRect {
  static func makeDefault() -> NSRect {
    let initialMargin = CGFloat(60)
    let fallback = NSRect(x: 0, y: 0, width: 100, height: 150)

    guard let screenFrame = NSScreen.main?.frame else {
      return fallback

    return NSRect(
      x: screenFrame.maxX - fallback.width - initialMargin,
      y: screenFrame.maxY - fallback.height - initialMargin,
      width: fallback.width, height: fallback.height)

extension NSMenu {
  static func makeMenu() -> NSMenu {
    let appMenu = NSMenuItem()
    appMenu.submenu = NSMenu()

        title: "Quit \(ProcessInfo.processInfo.processName)",
        action: #selector(NSApplication.terminate(_:)), keyEquivalent: "q"

    let mainMenu = NSMenu(title: "Main Menu")
    return mainMenu