iOS Code Snippet UserNotificationCenter class - Time sensitive notifications

Alexander Stolte · Jun 9, 2024

UserNotificationCenter class

A class that creates local notifications based on the newer iOS 10+ API. The notifications are configured to show even when the app is in the foreground. You can also add actions to the notifications: See the attached example

www.b4x.com

This is an addition to the UserNotificationCenter class.

I need a notification that is displayed on the lock screen and is not immediately pushed to the notification center. You can do this by declaring a notification as “time critical” via the UNNotificationInterruptionLevel.

UNNotificationInterruptionLevel | Apple Developer Documentation

Constants that indicate the importance and delivery timing of a notification.

developer.apple.com

UNNotificationInterruptionLevel.timeSensitive | Apple Developer Documentation

The system presents the notification immediately, lights up the screen, can play a sound, and breaks through system notification controls.

developer.apple.com

Thanks to @Erel for his answer here:

UserNotificationCenter - set interruptionLevel for time sensitive notifications

In my app, I need a notification that is displayed on the lock screen and is not immediately pushed to the notification center. You can do this by declaring a notification as “time critical”. Now I don't know how to integrate the whole thing correctly with Native Object. My following code...

www.b4x.com

Steps

Go to the Apple developer console
Open the Identifiers
Open the one from your app
Scroll down to "Time Sensitive Notifications" and check this option
save it and update your mobileprovision file from the app and download it

6. Add this line to the Project Attributes in the main module of your app

B4X:

#Entitlement: <key>com.apple.developer.usernotifications.time-sensitive</key><true/>

7. Open the "UserNotificationCenter" class and add the following line to the CreateNotificationWithContent sub

B4X:

Public Sub CreateNotificationWithContent(Title As String, Body As String, Identifier As String, Category As String, MillisecondsFromNow As Long)
    Dim ln As NativeObject
    ln = ln.Initialize("UNMutableNotificationContent").RunMethod("new", Null)
    ln.SetField("title", Title)
    ln.SetField("body", Body)
    ln.SetField("interruptionLevel", 2) 'Add this line - 2 = UNNotificationInterruptionLevelTimeSensitive
    Dim n As NativeObject
    ln.SetField("sound", n.Initialize("UNNotificationSound").RunMethod("defaultSound", Null))
    If Category <> "" Then ln.SetField("categoryIdentifier", Category)
    Dim trigger As NativeObject
    trigger = trigger.Initialize("UNTimeIntervalNotificationTrigger").RunMethod("triggerWithTimeInterval:repeats:", Array(MillisecondsFromNow / 1000, False))
    Dim request As NativeObject
    request = request.Initialize("UNNotificationRequest").RunMethod("requestWithIdentifier:content:trigger:", _
       Array(Identifier, ln, trigger))
    Dim NotificationCenter As NativeObject
    NotificationCenter = NotificationCenter.Initialize("UNUserNotificationCenter").RunMethod("currentNotificationCenter", Null)
    NotificationCenter.RunMethod("addNotificationRequest:", Array(request))
End Sub

8. Done

Open the app and the following item should now be available in the app settings on the iPhone:

The notification is marked as "Time sensitive" and is now visible at the lockscreen for 1 hour