Maui Local Notifications

.NET MAUI Local Notifications

Implementation overview

1. Define cross-platform INotificationManagerService interface and event args
2. Implement Android notification service (channel, AlarmManager, BroadcastReceiver)
3. Implement iOS/Mac Catalyst notification service (UNUserNotificationCenter)
4. Register platform implementations via DI
5. Configure platform permissions and MainActivity

See references/local-notifications-api.md for full implementation code.

Platform gotchas

Android

| Issue | Fix | |---|---| | Notifications silently fail on API 33+ | Must request POST_NOTIFICATIONS runtime permission first | | PendingIntent crash on Android 12+ | Must include PendingIntentFlags.Immutable for API 31+ | | Scheduled notifications lost on reboot | AlarmManager does not survive device restart — re-schedule on boot via BOOT_COMPLETED receiver | | No notification appears | Channel not created — required on API 26+ (Android 8.0) | | Notification tap doesn't return to app | LaunchMode = LaunchMode.SingleTop must be set on MainActivity |

// ✅ Correct — API 31+ requires Immutable flag
var pendingIntentFlags = (Build.VERSION.SdkInt >= BuildVersionCodes.S)
    ? PendingIntentFlags.CancelCurrent | PendingIntentFlags.Immutable
    : PendingIntentFlags.CancelCurrent;

// ❌ Wrong — crashes on Android 12+
var pendingIntentFlags = PendingIntentFlags.CancelCurrent;

iOS / Mac Catalyst

| Issue | Fix | |---|---| | No notification prompt appears | Permission already denied — user must re-enable in Settings | | Foreground notifications don't show | Must implement UNUserNotificationCenterDelegate and set Current.Delegate | | Notification shows Alert not Banner | Use UNNotificationPresentationOptions.Banner on iOS 14+ |

// ✅ iOS 14+ — use Banner
completionHandler(OperatingSystem.IsIOSVersionAtLeast(14)
    ? UNNotificationPresentationOptions.Banner
    : UNNotificationPresentationOptions.Alert);

// ❌ Always using Alert — deprecated on iOS 14+
completionHandler(UNNotificationPresentationOptions.Alert);

Windows

⚠️ Windows App SDK supports toast notifications but scheduled notifications are not yet supported. Immediate notifications work.

DI registration — platform-specific only

// ✅ Must use #if guards — there's no cross-platform implementation
#if ANDROID
    builder.Services.AddTransient();
#elif IOS
    builder.Services.AddTransient();
#elif MACCATALYST
    builder.Services.AddTransient();
#endif

Common anti-patterns

// ❌ Sending without checking permission — silent failure on API 33+
notificationManager.SendNotification("Title", "Body");

// ✅ Request permission first
#if ANDROID
var status = await Permissions.RequestAsync();
if (status != PermissionStatus.Granted) return;
#endif

// ❌ Updating UI directly from notification callback — cross-thread exception
notificationManager.NotificationReceived += (s, e) =>
    myLabel.Text = ((NotificationEventArgs)e).Title;

// ✅ Marshal to UI thread
notificationManager.NotificationReceived += (s, e) =>
    MainThread.BeginInvokeOnMainThread(() =>
        myLabel.Text = ((NotificationEventArgs)e).Title);

Decision framework

| Need | Approach | |---|---| | Immediate notification | SendNotification(title, message) with null notifyTime | | Scheduled reminder | SendNotification(title, message, DateTime.Now.AddMinutes(30)) | | Persist across reboot (Android) | Add BOOT_COMPLETED receiver to re-schedule alarms | | Rich notifications (images, actions) | Extend platform implementations with native APIs | | Push notifications from server | Use a different pattern entirely (FCM/APNs) |

Quick checklist

• [ ] Cross-platform INotificationManagerService interface defined
• [ ] Android: notification channel created (API 26+)
• [ ] Android: POST_NOTIFICATIONS permission in manifest + runtime request (API 33+)
• [ ] Android: PendingIntentFlags.Immutable used (API 31+)
• [ ] Android: MainActivity has LaunchMode.SingleTop and handles OnNewIntent
• [ ] iOS: UNUserNotificationCenterDelegate set for foreground display
• [ ] iOS: Banner used instead of Alert on iOS 14+
• [ ] DI registration uses #if platform guards
• [ ] UI updates from notification callbacks use MainThread.BeginInvokeOnMainThread

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: davidortinau
• Source: davidortinau/maui-skills
• License: MIT

Install and usage instructions live in the source repository linked above.