Xamarin.Forms (Android) に Azure Notification Hubs からタグを活用して Push 通知を送る

namespace PushDemoAndroid.Droid
{
    [Service]
    [IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
    [IntentFilter(new[] { "com.google.firebase.INSTANCE_ID_EVENT" })]
    public class MyFirebaseMessagingService : FirebaseMessagingService
    {
        ...
    }
}

const string TAG = "MyFirebaseMsgService";
NotificationHub hub;

public override void OnMessageReceived(RemoteMessage message)
{
    Log.Debug(TAG, "From: " + message.From);
    if (message.GetNotification() != null)
    {
        //These is how most messages will be received
        Log.Debug(TAG, "Notification Message Body: " + message.GetNotification().Body);
        SendNotification(message.GetNotification().Body);
    }
    else
    {
        //Only used for debugging payloads sent from the Azure portal
        SendNotification(message.Data.Values.First());

    }
}

void SendNotification(string messageBody)
{
    var intent = new Intent(this, typeof(MainActivity));
    intent.AddFlags(ActivityFlags.ClearTop);
    var pendingIntent = PendingIntent.GetActivity(this, 0, intent, PendingIntentFlags.OneShot);

    var notificationBuilder = new NotificationCompat.Builder(this, MainActivity.CHANNEL_ID);

    // edit Content Title for notification title
    notificationBuilder.SetContentTitle("Push Demo Android")
                .SetSmallIcon(Resource.Drawable.ic_launcher)
                .SetContentText(messageBody)
                .SetAutoCancel(true)
                .SetShowWhen(false)
                .SetContentIntent(pendingIntent);

    var notificationManager = NotificationManager.FromContext(this);

    notificationManager.Notify(0, notificationBuilder.Build());
}

public override void OnNewToken(string token)
{
    Log.Debug(TAG, "FCM token: " + token);
    SendRegistrationToServer(token);
}

void SendRegistrationToServer(string token)
{
    // Register with Notification Hubs
    hub = new NotificationHub(Constants.NotificationHubName,
                                Constants.ListenConnectionString, this);

    var dt = DateTime.Now;
    var timeTag = dt.ToString("HH:mm:ss");

    var carVendor = "";
    var vendorType = "";
    var vendorLocation = "";
    var carGrade = "";
    switch (Convert.ToInt64(dt.Minute) % 10) {
        case 0: case 1: case 2: case 3:
            carVendor = "TOYOTA";
            vendorType = "JapaneseCar";
            vendorLocation = "Aichi";
            carGrade = "20";
            break;
        case 4: case 5: case 6:
            carVendor = "NISSAN";
            vendorType = "JapaneseCar";
            vendorLocation = "Kanagawa";
            carGrade = "15";
            break;
        case 7: case 8: case 9:
            carVendor = "BMW";
            vendorType = "ForeignCar";
            vendorLocation = "Munich";
            carGrade = "10";
            break;
        default:
            carVendor = "tmp1";
            vendorType = "tmp2";
            vendorLocation = "tmp3";
            carGrade = "tmp4";
            break;
    }

    var tags = new List<string>() {timeTag, carVendor, vendorType, vendorLocation, carGrade};
    var regID = hub.Register(token, tags.ToArray()).RegistrationId;

    Log.Debug(TAG, $"Successful registration of ID {regID}");
}