Scheduling & Triggers

Overview

Notifications can be triggered at a specific time, on a repeating schedule, or when the user enters a geographic area.

Note

A notification can only have one trigger type. You cannot combine ScheduleDate, RepeatInterval, and Geofence on the same notification.

Scheduled Notifications

Display a notification at a specific date and time.

INotificationManager notifications; // injected

await notifications.Send(new Notification
{
    Title = "Reminder",
    Message = "Don't forget your meeting!",
    ScheduleDate = DateTimeOffset.Now.AddHours(1)
});

// Or using the extension method
await notifications.Send(
    "Reminder",
    "Don't forget your meeting!",
    scheduleDate: DateTime.Now.AddHours(1)
);

Repeating Notifications

Use IntervalTrigger to create repeating notifications.

// Repeat every 4 hours
await notifications.Send(new Notification
{
    Title = "Check In",
    Message = "Time for your health check-in",
    RepeatInterval = new IntervalTrigger
    {
        Interval = TimeSpan.FromHours(4)
    }
});

// Repeat at a specific time of day
await notifications.Send(new Notification
{
    Title = "Daily Digest",
    Message = "Your daily summary is ready",
    RepeatInterval = new IntervalTrigger
    {
        TimeOfDay = new TimeSpan(9, 0, 0)  // 9:00 AM
    }
});

// Repeat on a specific day and time
await notifications.Send(new Notification
{
    Title = "Weekly Report",
    Message = "Your weekly report is ready",
    RepeatInterval = new IntervalTrigger
    {
        DayOfWeek = DayOfWeek.Monday,
        TimeOfDay = new TimeSpan(8, 0, 0)  // Monday at 8:00 AM
    }
});

Geofence Notifications

Trigger a notification when the user enters a geographic area. Requires AccessRequestFlags.LocationAware.

// First, request location-aware access
await notifications.RequestAccess(
    AccessRequestFlags.Notification | AccessRequestFlags.LocationAware
);

await notifications.Send(new Notification
{
    Title = "Welcome!",
    Message = "You've arrived at the store",
    Geofence = new GeofenceTrigger
    {
        Center = new Position(43.6532, -79.3832),  // latitude, longitude
        Radius = Distance.FromMeters(200),
        Repeat = false  // Fire only once
    }
});

iOS Time Sensitive Notifications

For time-critical notifications on iOS, request the TimeSensitivity flag.

Time Sensitive notifications require the Time Sensitive Notifications entitlement in your Apple Developer account and proper provisioning profile configuration.

var access = await notifications.RequestAccess(
    AccessRequestFlags.Notification | AccessRequestFlags.TimeSensitivity
);

Android Exact Alarms

Scheduled notifications on Android are delivered through the OS AlarmManager. Since Android 12 (API 31), firing an alarm at an exact time requires the special-access exact alarm permission. Without it, calling for an exact alarm throws a SecurityException - which previously meant your scheduled notification was silently dropped and never appeared.

Shiny now degrades gracefully: if exact alarm access has not been granted, the notification is scheduled as an inexact alarm instead. It will still fire, but the OS may batch or delay it slightly to save power. A warning is logged so you can see this happen during development.

To get exact, on-time delivery, request the TimeSensitivity flag. On Android this checks AlarmManager.CanScheduleExactAlarms() and, when needed, sends the user to the system settings screen to grant exact alarm access:

var access = await notifications.RequestAccess(
    AccessRequestFlags.Notification | AccessRequestFlags.TimeSensitivity
);

Declare the matching permission in your AndroidManifest.xml. There are two valid setups - pick one based on what kind of app you ship.

Most apps (notifications are a feature, not the core purpose) - declare SCHEDULE_EXACT_ALARM on all API levels so the TimeSensitivity settings prompt can grant it:

<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" />

On API 31-32 this is auto-granted; on API 33+ it is user-grantable through the “Alarms & reminders” settings screen that TimeSensitivity navigates to.

Genuine alarm-clock / reminder apps (core function is alarms, timers, or calendar reminders) - cap SCHEDULE_EXACT_ALARM at API 32 and add USE_EXACT_ALARM, which is auto-granted and non-revocable on API 33+ without sending the user to settings:

<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" android:maxSdkVersion="32" />
<uses-permission android:name="android.permission.USE_EXACT_ALARM" />

Caution

Do not cap SCHEDULE_EXACT_ALARM with android:maxSdkVersion="32" unless you also declare USE_EXACT_ALARM. If you do, your app has no exact-alarm permission on Android 13+ (API 33+): CanScheduleExactAlarms() returns false, the “Alarms & reminders” toggle appears greyed out and unchecked (the user cannot enable it), and every scheduled notification silently uses the delayed inexact fallback.

Note

USE_EXACT_ALARM is restricted by Google Play to apps whose core function is alarms, timers, or calendar reminders. If your app does not qualify, use the first (uncapped SCHEDULE_EXACT_ALARM) setup and rely on the TimeSensitivity settings prompt or the inexact fallback.