Android Auto Notifications

[Gekidoku]

Hello MAUI community.
Im in a bit of a bind. My app is used by security guards.
One part of the app is that dispatch can send alarm notifications to a security guard thats driving around notifying him of a potential burglary.
As you may imagine this is a high importance notification.
This works all well and good in regular use. Untill the security guard's phone connects to android auto.
Then the notification is just shown on the device and the sound that normally plays is silent.
So a guard can go a while without noticing.

So far I tried the following.

In my Android platform files.
In my notification handler I added a carExtender.

var notificationBuilder = new NotificationCompat.Builder(context, chanId)
     .SetSmallIcon(smallIconResource)
     .SetContentTitle(title)
     .SetContentText(message)
     .SetAutoCancel(true)
     .SetWhen(Java.Lang.JavaSystem.CurrentTimeMillis())
     .SetContentIntent(pendingIntent)
     .SetCategory(NotificationCompat.CategoryMessage)
     .SetPriority(NotificationCompat.PriorityHigh)
     .SetVisibility(NotificationCompat.VisibilityPublic)
     .SetAllowSystemGeneratedContextualActions(true);

var carExtender = new NotificationCompat.CarExtender()
.SetColor(notificationColor ?? Color.Blue)
.SetLargeIcon(null)  // Optional: you can set a car-specific large icon
.SetUnreadConversation(null);  // We're using MessagingStyle instead
notificationBuilder.Extend(carExtender);

I tried changing the style and adding actions.

 var appName = context.ApplicationInfo.LoadLabel(context.PackageManager);

 var sender = new AndroidX.Core.App.Person.Builder()
 .SetName(appName)
 .SetImportant(true)
 .Build();
 var messages = new List<NotificationCompat.MessagingStyle.Message>
 {
     new NotificationCompat.MessagingStyle.Message(
      message,
      Java.Lang.JavaSystem.CurrentTimeMillis(),
      sender)
 };
 var messagingStyle = new NotificationCompat.MessagingStyle(sender)
 .SetConversationTitle(title)
 .SetGroupConversation(false);
 foreach (var msg in messages)
 {
     messagingStyle.AddMessage(msg);
 }

 notificationBuilder.SetStyle(messagingStyle);

 var AcceptIntent = new Intent(context, typeof(PushNotificationReadReceiver));
 AcceptIntent.SetAction("ACTION_ACCEPT");

 AcceptIntent.PutExtra("notification_id", notifyId);
 AcceptIntent.PutExtra("message", message);
 AcceptIntent.PutExtras(extras);
 var readPendingIntent = PendingIntent.GetBroadcast(
 context,
 1,
 AcceptIntent,
 PendingIntentFlags.UpdateCurrent | PendingIntentFlags.Mutable);

 var AcceptAction = new NotificationCompat.Action.Builder(
 0, // You'll need this drawable resource
 "Accepteren",
 readPendingIntent).SetSemanticAction(NotificationCompat.Action.SemanticActionMarkAsRead)
 .Build();


 var declineIntent = new Intent(context, typeof(PushNotificationReadReceiver));
 declineIntent.SetAction("ACTION_DECLINE");
 declineIntent.PutExtra("notification_id", notifyId);
 declineIntent.PutExtras(extras);

 var declinePendingIntent = PendingIntent.GetBroadcast(
     context,
     3,  // Unique request code
     declineIntent,
     PendingIntentFlags.UpdateCurrent | PendingIntentFlags.Mutable);

 var declineAction = new NotificationCompat.Action.Builder(
     0,  // No icon
     "Weigeren",
     declinePendingIntent)
     .Build();

 notificationBuilder.AddAction(AcceptAction);
 notificationBuilder.AddAction(declineAction);

My notification Channel

var notificationchannel = new NotificationChannel("MyChannel", "MyChannel", NotificationImportance.High);

var sounduri = Android.Net.Uri.Parse("android.resource://" + PackageName + "/" + MyApp.Resource.Raw.horn);
var type = new AudioAttributes.Builder().SetContentType(AudioContentType.Sonification).SetUsage(AudioUsageKind.Notification).SetLegacyStreamType(Android.Media.Stream.Notification).Build();
notificationchannel.SetSound(sounduri, type);
notificationchannel.SetShowBadge(true);
notificationchannel.EnableLights(true);
notificationchannel.EnableVibration(true);

notificationchannel.LockscreenVisibility = NotificationVisibility.Public;

var manager = (NotificationManager)GetSystemService(NotificationService);
NotificationChannel existingChannel = manager.GetNotificationChannel("MyChannel");

if (existingChannel != null)
{
    // Delete the existing channel
    manager.DeleteNotificationChannel("MyChannel");
}
 manager.CreateNotificationChannel(notificationchannel);

Added the following to my manifest

<uses-feature android:name="android.hardware.type.automotive" android:required="false" />
inside my application
  <meta-data
  android:name="com.google.android.gms.car.application"
  android:resource="@xml/automotive_app_desc" />

But to no avail so far.

[ghost]

@Gekidoku, by "device" do you mean Android Auto or the phone?

For audio, did you try different Auto players?

Random knowledge:

• https://github.com/jfversluis/Plugin.Maui.Audio/blob/main/docs/audio-player.md#configure-the-playback-options
• https://developer.android.com/reference/android/media/AudioAttributes
• https://developer.android.com/reference/android/media/AudioAttributes#CONTENT_TYPE_SONIFICATION

I found it important to initialize the audio player once and reuse it many times; otherwise it is too slow for an Auto click handler. This is true for CarPlay. For Android Auto I am still searching for the optimal audio player that will work reliably. I am also searching knowledge to support disconnects and reconnects, which can happen if someone calls you during an Android Auto session.