Thoughts, stories and ideas.

11th September 2016 · 6 minutes · macos

User Notifications notify the user that something has changed in the application. Best known examples are the upcoming events in Calendar or the build status in Xcode.

Notification Center provides an overview of notifications from applications. As we will see, it’s very easy to integrate and display basic notifications in it.

Three display styles are available: None, Banner and Alert. By default, User Notifications are displayed using the Banner style.


We use two objects:

  • NSUserNotification: to create and manage the notification
  • NSUserNotificationCenter: to display the notification
import Cocoa

// Create the notification and setup information

let notification = NSUserNotification()
notification.identifier = UUID().uuidString
notification.title = "Hello"
notification.subtitle = "How are you?"
notification.informativeText = "This is a test"
notification.soundName = NSUserNotificationDefaultSoundName
notification.contentImage = NSImage(contentsOf: URL(string: "https://placehold.it/300")!)

// Delegate of the Notification Center

let notificationCenter = NSUserNotificationCenter.default

// Manually display the notification


However this piece of code does not really display the notification, the Notification Center decides if it should be displayed or not. Usually, the notification it’s not display if the app is already in focus.

To do that, we need to implement NSUserNotificationCenterDelegate protocol. AppDelegate’s applicationDidFinishLaunching method is a good candidate. You can force a notification to be displayed, thanks to userNotificationCenter:shouldPresent.

notificationCenter.delegate = self


func userNotificationCenter(_ center: NSUserNotificationCenter, shouldPresent notification: NSUserNotification) -> Bool {
	return true


Banners are simple notification view, dismissed after a few seconds.

A simple banner notification
A simple banner notification


On the contrary of banners, alerts aren’t dismissed automatically.

A simple alert notification
A simple alert notification

To modify the notification style we need to add a property into Info.plist. Set NSUserNotificationAlertStyle as key with alert string value.


Adding an action


We can add a reply field with a custom placeholder.

notification.hasReplyButton = true
notification.responsePlaceholder = "Type you reply here"
A notification with reply — hover
A notification with reply — hover
A notification with reply — focus
A notification with reply — focus

Handle response

After the user validated his response, the Notification Center will call userNotificationCenter:didActivate, we just need to check the activation type:

func userNotificationCenter(_ center: NSUserNotificationCenter, didActivate notification: NSUserNotification) {
    switch (notification.activationType) {
        case .replied:
            guard let res = notification.response else { return }
            print("User replied: \(res.string)")


By default, on alert you’ll have default buttons, like displayed before. We can configure them, to match what you want.

notification.hasActionButton = true
notification.otherButtonTitle = "Marco"
notification.actionButtonTitle = "Polo"
A notification with custom buttons title
Custom buttons title

Additional actions

It’s sometimes useful to offer multiple actions to users, directly from the notification, as a non-breaking workflow.

Additional actions are an array of NSUserNotificationAction:

notification.additionalActions = [
    NSUserNotificationAction(identifier: "action1", title: "Action 1"),
    NSUserNotificationAction(identifier: "action2", title: "Action 2"),
    NSUserNotificationAction(identifier: "action3", title: "Action 3")
A notification with additional actions displayed
Additional actions displayed

Currently, you need to hold-click the action button to display the additional actions and there is no little arrow on hover.

Handle actions

Go back to userNotificationCenter:didActivateNotification and add these switch cases:

case .additionalActionClicked:
    guard let choosen = notification.additionalActivationAction, let title = choosen.title else { return }
    print("Action: \(title)")
case .actionButtonClicked:
    print("Action button (Polo)")
case .contentsClicked:
    print("Contents clicked")


Finally, let’s say we want to schedule the display to be 10 seconds later and then to repeat it every day.

notification.deliveryDate = NSDate(timeIntervalSinceNow: 10)

let repeatInt = NSDateComponents()
repeatInt.day = 1
notification.deliveryRepeatInterval = repeatInt


Notice, that instead of deliver, we used schedule function.

Last updated on 19th August 2019