Minimal FCM Push Messaging for .NET MAUI (RC3)

README

* Setup Firebase project like normal and add google-services.json (make sure Build action is set to GoogleServicesJson)
* Nugets required for MAUI project file (later versions don't work)

    <ItemGroup Condition="'$(TargetFramework)' == 'net6.0-android'">
        <PackageReference Include="Xamarin.Firebase.Iid" Version="121.1.0" />
        <PackageReference Include="Xamarin.Firebase.Messaging" Version="122.0.0" />
        <PackageReference Include="Xamarin.Google.Dagger" Version="2.39.1" />
        <PackageReference Include="Xamarin.GooglePlayServices.Base" Version="117.6.0.5" />
    </ItemGroup>
    

FCMService.cs

using Android.App;
using Android.Content;
using AndroidX.Core.App;
using Firebase.Messaging;

namespace FCMApp.Android;

[Service(Exported = false)]
[IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
public class FCMService : FirebaseMessagingService
{
    public override void OnMessageReceived(RemoteMessage message)
    {
        RemoteMessage.Notification notification = message.GetNotification();

        IDictionary<string, string> data = message.Data;
        string body = "";
        string title = "";

        if (data != null && data.ContainsKey("body") && data.ContainsKey("title"))
        {
            body = data["body"];
            title = data["title"];
        }
        else if (notification != null)
        {
            body = message.GetNotification().Body;
            title = message.GetNotification().Title;
        }
        if (!string.IsNullOrEmpty(body) && !string.IsNullOrEmpty(title))
        {
            // TODO: Manage this message (we get here only when app is in foreground)
        }
    }

}

IMessagingService.cs

namespace FCMApp;

public interface IMessagingService
{
    string GetToken();
    bool IsMessagingAvailable();
    void SetNewTokenCallback(Action<string> token_callback);
}
    

MessagingService.Android.cs

using Android.Gms.Common;
using Android.Gms.Tasks;
using Firebase.Iid;

namespace FCMApp;

public partial class MessagingService
{
    public partial bool IsMessagingAvailable() => GoogleApiAvailability.Instance.IsGooglePlayServicesAvailable(Android.App.Application.Context) == ConnectionResult.Success;
    public partial string GetToken() => FirebaseInstanceId.Instance.Token;
    public partial void SetNewTokenCallback(Action<string> token_callback)
    {
        if (token_callback == null)
            throw new InvalidOperationException("Callback cannot be null");
        
        if (GetToken() != null)
            token_callback(GetToken());
        else
            FirebaseInstanceId.Instance.GetInstanceId().AddOnSuccessListener(new OnTokenListener((token) => token_callback(token)));
    }
}

public class OnTokenListener : Java.Lang.Object, IOnSuccessListener
{
    Action<string> _callback;
    public OnTokenListener(Action<string> success_callback) => _callback = success_callback;
    public void OnSuccess(Java.Lang.Object result) => _callback?.Invoke(FirebaseInstanceId.Instance.Token);
}

MessagingService.cs

namespace FCMApp;

public partial class MessagingService : IMessagingService
{
    public partial string GetToken();
    public partial bool IsMessagingAvailable();
    public partial void SetNewTokenCallback(Action<string> token_callback);
}

This was very helpful ! Thanks :)

Do you have something similar on how to use FCM on iOS with MAUI ? Or which library works with current MAUI version for pushing notifications on iOS ?

Thanks @peter-bozovic ! Did you get it to work with this?

I don't have anything for iOS right now yet

This code gave me some first results and put me on the right track. (mostly the working packages and OnMessageReceived service)
However it uses a lot of obsolete methods so I had to rewrite almost everything from parts found in different projects / documentations / samples ...

Do we have any way to implement push notification sin MAUI

@AnjanaJois20 this code is for .NET MAUI or Xamarin.Forms for that matter. There is no difference between it

FirebaseInstanceId is deprecated.

I just put together a tutorial how to get work FCM and .NET MAUI for iOS platform. Hopefully will help someone...

Awesome @michalpr! Thanks for that!

@maurobernal
Replace the deprecated FirebaseInstanceId with FirebaseMessaging.

- FirebaseInstanceId.Instance.Token -> (string)FirebaseMessaging.Instance.GetToken().Result
- FirebaseInstanceId.Instance.GetInstanceId().AddOnSuccessListener(... -> FirebaseMessaging.Instance.GetToken().AddOnSuccessListener(...
- .Invoke(FirebaseInstanceId.Instance.Token) -> .Invoke((string)FirebaseMessaging.Instance.GetToken()

I have a clarifying question. How can I send a push inside my application to a user via FCM using the Messaging Service or FCMService? Please give examples