Grouping notifications
Organize notifications into threads.
Overview
The system groups related notifications together in the Notification Center. You can control how watchOS groups your app’s notifications by adding a thread identifier.
Set the thread identifier
The system automatically groups notifications with the same category and thread ID as they arrive. For local notifications, set the content’s threadIdentifier property. For remote notifications, use the thread-id key.
let myPOICategory = "NearbyPlaceOfInterestCategoryIdentifier"
let myPOIThread = "NearbyPlaceOfInterestThreadIdentifier"
// Create the local notification's content.
let content = UNMutableNotificationContent()
content.title = "Grand Canyon"
content.body = "You are within 50 miles of the Grand Canyon"
// Enable grouping by adding a thread identifier.
content.threadIdentifier = myPOIThread
// Then create the request for the notification.
let request = UNNotificationRequest(identifier: myPOICategory,
content: content)Display groups in custom interfaces
Additionally, if you provide a custom long-look interface, it can respond to grouped notifications, displaying content from multiple notifications within a single interface. If a custom notification interface is on screen and a new notification with a matching category and thread ID arrives, the system calls your notification controller’s didReceive(_:) method again. Your implementation must be prepared to append the incoming content to the existing interface. For example, if your custom interface displays the content in a table view, you can add a new row for the incoming content.