MAUI - push notifications support

Question

I couldn't find any documentation of how to implement push notifications in maui. Maybe somebody was able to integrate xamarin library in maui project to accomplish it?

score 8 · Answer 1 · answered Sep 01 '21 at 18:54

.NET MAUI is still in preview so while "kicking tires" is happening a lot, no one should actually use this in production. Bits are still in progress, as well as documentation and third-party libraries.

Having that said, concepts like push notifications actually won't change that much. Push notifications still happen very much on the platform-specific layer. If you, for instance, follow this guide, you'll see that it speaks of a MainActivity for Android, that will still be there, although in a different place. Same for the AppDelegate in iOS.

You have to translate some concepts to .NET MAUI but it shouldn't be too complicated to figure it out. But if you can't and have time, wait a bit longer the libraries and documentation will catch up!

Hi Gerald, hasn't it been updated or changed since this solution was suggested? — Yasir Arafat, Aug 30 '22 at 18:35

score 5 · Answer 2 · answered Oct 25 '22 at 13:29

Hopefully the tutorial below will help you to enable Firebase Cloud Messaging for .NET MAUI project on iOS platform.

Preparation

I consider you have set up the Apple provisioning profile properly. This means you set up Certificate, Identifier and Profile (especially Distribution - App Store) on Apple Developer Site. Do not forget to enable "Push Notification" on Identifier page of your application and use the same Bundle ID as you are using in your app. On Keys page configure the APN Key - check "Apple Push Notifications service (APNs)" - download it and remember Key ID. You will need it in the Firebase Console.

I also consider all preparation work on Firebase Console is done according to tutorial and you have the GoogleService-Info.plist file ready (but not added to your project). Do not forget to register APNs Authentication Key on page Project setting, tab "Cloud Messaging", part "Apple app configuration".

Project changes

Having all this done let's open solution with MAUI project in Visual Studio 2022. In my case version 17.3.6, .NET SDK 6.0.402, MAUI workload 6.0.541, build server macOS Monterey 12.6 with Xcode 14.0.1.

Check "Target iOS Framework" in project properties is set to "net6.0-ios15.4" and then add nuget package "Xamarin.Firebase.iOS.CloudMessaging" version 8.10.0.2 in traditional way using Nuget Package Manager.

You can run into an issue with a long path. Package installation might fail with exception "System.IO.DirectoryNotFoundException: Could not find a part of the path 'C:\Users\...\.nuget\packages\xamarin.firebase.ios.installations\...\FirebaseInstallations-umbrella.h'." But you can solve it by adding Nuget.config file into solution folder with this content:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <config>
    <clear />
    <add key="globalPackagesFolder" value="C:\Nuget" />
  </config>
</configuration>

Add Entitlements.plist file into Platforms\iOS folder with this content:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>aps-environment</key>
    <string>development</string>
</dict>
</plist>

Add into Info.plist file these rows:

<key>UIBackgroundModes</key>
<array>
    <string>remote-notification</string>
</array>

You can include generated GoogleService-Info.plist by adding these lines into project file:

<ItemGroup Condition="'$(TargetFramework)'=='net6.0-ios15.4'">
    <BundleResource Include="Platforms\iOS\GoogleService-Info.plist" />
</ItemGroup>

... and let the Firebase package to read settings from it but let's keep it simpler and do not add this file to project.

Instead, change file Platforms\iOS\AppDelegate.cs like this:

using Firebase.CloudMessaging;
using Foundation;
using UIKit;
using UserNotifications;

namespace ...

[Register("AppDelegate")]
public class AppDelegate : MauiUIApplicationDelegate, IUNUserNotificationCenterDelegate, IMessagingDelegate
{
    protected override MauiApp CreateMauiApp() => MauiProgram.CreateMauiApp();

    public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
    {
        ...

        var result = base.FinishedLaunching(application, launchOptions);

        var authOptions = UNAuthorizationOptions.Alert | UNAuthorizationOptions.Badge | UNAuthorizationOptions.Sound;
        UNUserNotificationCenter.Current.RequestAuthorization(authOptions, (granted, error) =>
        {
            this.Log($"RequestAuthorization: {granted}" + (error != null ? $" with error: {error.LocalizedDescription}" : string.Empty));

            if (granted && error == null)
            {
                this.InvokeOnMainThread(() =>
                {
                    UIApplication.SharedApplication.RegisterForRemoteNotifications();
                    this.InitFirebase();
                });
            }
        });

        return result;
    }

    private void InitFirebase()
    {
        this.Log($"{nameof(this.InitFirebase)}");

        try
        {
            var options = new Firebase.Core.Options("[GOOGLE_APP_ID]", "[GCM_SENDER_ID]");
            options.ApiKey = "[API_KEY]";
            options.ProjectId = "[PROJECT_ID]";
            options.BundleId = "[BUNDLE_ID]";
            options.ClientId = "[CLIENT_ID]";

            Firebase.Core.App.Configure(options);
        }
        catch (Exception x)
        {
            this.Log("Firebase-configure Exception: " + x.Message);
        }

        UNUserNotificationCenter.Current.Delegate = this;

        if (Messaging.SharedInstance != null)
        {
            Messaging.SharedInstance.Delegate = this;
            this.Log("Messaging.SharedInstance SET");
        }
        else
        {
            this.Log("Messaging.SharedInstance IS NULL");
        }
    }

    // indicates that a call to RegisterForRemoteNotifications() failed
    // see developer.apple.com/documentation/uikit/uiapplicationdelegate/1622962-application
    [Export("application:didFailToRegisterForRemoteNotificationsWithError:")]
    public void FailedToRegisterForRemoteNotifications(UIApplication application, NSError error)
    {
        this.Log($"{nameof(FailedToRegisterForRemoteNotifications)}: {error?.LocalizedDescription}");
    }

    // this callback is called at each app startup
    // it can be called two times:
    //   1. with old token
    //   2. with new token
    // this callback is called whenever a new token is generated during app run
    [Export("messaging:didReceiveRegistrationToken:")]
    public void DidReceiveRegistrationToken(Messaging messaging, string fcmToken)
    {
        this.Log($"{nameof(DidReceiveRegistrationToken)} - Firebase token: {fcmToken}");

        //Utils.RefreshCloudMessagingToken(fcmToken);
    }

    // the message just arrived and will be presented to user
    [Export("userNotificationCenter:willPresentNotification:withCompletionHandler:")]
    public void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
    {
        var userInfo = notification.Request.Content.UserInfo;

        this.Log($"{nameof(WillPresentNotification)}: " + userInfo);

        // tell the system to display the notification in a standard way
        // or use None to say app handled the notification locally
        completionHandler(UNNotificationPresentationOptions.Alert);
    }

    // user clicked at presented notification
    [Export("userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:")]
    public void DidReceiveNotificationResponse(UNUserNotificationCenter center, UNNotificationResponse response, Action completionHandler)
    {
        this.Log($"{nameof(DidReceiveNotificationResponse)}: " + response.Notification.Request.Content.UserInfo);
        completionHandler();
    }

    void Log(string msg)
    {
        ...
    }
}

... and change Options values to correct ones from your GoogleService-Info.plist file...

Build and test

Now, you can build the project!

Beware, Firebase iOS CloudMessaging works only in Release mode. In Debug mode Configure method fails with message "Could not create an native instance of the type 'Firebase.Core.Options': the native class hasn't been loaded", no matter you test on physical device with properly set manual Provisioning profile. So, we can test messaging using TestFlight or AdHoc distribution only.

The easiest way for sending test notification messages is to use Firebase Console. Just open Cloud Messaging item in Engage menu and tap "Send your first message" button. Fill in "Notification text" field and tap "Send test message", fill in token in field "Add an FCM registration token" (you got it from log file of your iOS app) and tap "Test" button.

MAUI - push notifications support

3 Answers3

Preparation

Project changes

Build and test

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