I've seen many different types of solutions which may have worked in the past, but nothing solid that has worked for myself. And it's a minefield of what people say works, what doesn't work, what has changed, etc. But I'm trying to find not only a solution but hopefully an understanding - because right now I am seriously confused.
What I can do right now - My Xamarin Forms app (Android) can receive push notification if the app is in the Foreground/Background, I can also intercept these notifications when the user taps them so I can tell my app what to do.
What I am trying to do - Essentially the above but in the state of where the app has been completely stopped.
I have my Firebase Messaging setup which is wired to Azure Notification Hub - unfortunately, I won't be moving away from Azure (just in case anyone suggests to drop it). Most of what I have currently is information I've managed to stitch together from various Microsoft Documentation (here I don't use AppCenter - just used this to cross-reference any useful code, here, here, and here ), other StackOverflow questions (such as here, here, and here - far too many more to link) and the Xamarin forum - so again, apologies if there is any obsolete code being used (please let me know - I have tried my best to use up-to-date methods, etc).
The type of push notifications that I am sending are Data Messages which I read up on here, I'm using custom data in my notifications therefore it is my understanding this is the correct type of push I want to send, as shown below.
{
"data": {
"title": "Title Test",
"body": "Push notification body test",
"area": "SelectedPage"
}
}
Below is the current code I have setup in my project to handle push notifications thus far.
Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="com.companyname.pushtesting" android:installLocation="auto">
<uses-sdk android:minSdkVersion="21" android:targetSdkVersion="28" />
<application android:label="Push Testing">
<receiver android:name="com.google.firebase.iid.FirebaseInstanceIdInternalReceiver" android:exported="false" />
<receiver android:name="com.google.firebase.iid.FirebaseInstanceIdReceiver" android:exported="true" android:permission="com.google.android.c2dm.permission.SEND">
<intent-filter>
<action android:name="com.google.android.c2dm.intent.RECEIVE" />
<action android:name="com.google.android.c2dm.intent.REGISTRATION" />
<category android:name="${applicationId}" />
</intent-filter>
</receiver>
</application>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
</manifest>
MainActivity.cs
I have LaunchMode = LaunchMode.SingleTop, would my understanding be correct, for this is to ensure the current Activity is still used instead of creating a new one - for instance, when the user would tap a notification - implementing it plus additional code (below) seems to suggest this is true.
protected override void OnNewIntent(Intent intent) {
base.OnNewIntent(intent);
String area = String.Empty;
String extraInfo = String.Empty;
if (intent.Extras != null) {
foreach (String key in intent.Extras.KeySet()) {
String value = intent.Extras.GetString(key);
if (key == "Area" && !String.IsNullOrEmpty(value)) {
area = value;
} else if (key == "ExtraInfo" && !String.IsNullOrEmpty(value)) {
extraInfo = value;
}
}
}
NavigationExtension.HandlePushNotificationNavigation(area, extraInfo);
}
Using OnNewIntent to intercept the push notification when the user interacts with it.
MyFirebaseMessaging.cs
using System;
using System.Threading.Tasks;
using Android.App;
using Android.Content;
using Android.Support.V4.App;
using Android.Util;
using Firebase.Messaging;
using PushTesting.Models;
using WindowsAzure.Messaging;
namespace PushTesting.Droid.Services {
[Service]
[IntentFilter(new[] { "com.google.firebase.MESSAGING_EVENT" })]
public class OcsFirebaseMessaging : FirebaseMessagingService {
private const String NotificationChannelId = "1152";
private const String NotificationChannelName = "Push Notifications";
private const String NotificationChannelDescription = "Receive notifications";
private NotificationManager notificationManager;
public override void OnNewToken(String token) => SendTokenToAzure(token);
/// <summary>
/// Sends the token to Azure for registration against the device
/// </summary>
private void SendTokenToAzure(String token) {
try {
NotificationHub hub = new NotificationHub(Constants.AzureConstants.NotificationHub, Constants.AzureConstants.ListenConnectionString, Android.App.Application.Context);
Task.Run(() => hub.Register(token, new String[] { }));
} catch (Exception ex) {
Log.Error("ERROR", $"Error registering device: {ex.Message}");
}
}
/// <summary>
/// When the app receives a notification, this method is called
/// </summary>
public override void OnMessageReceived(RemoteMessage remoteMessage) {
Boolean hasTitle = remoteMessage.Data.TryGetValue("title", out String title);
Boolean hasBody = remoteMessage.Data.TryGetValue("body", out String body);
Boolean hasArea = remoteMessage.Data.TryGetValue("area", out String area);
Boolean hasExtraInfo = remoteMessage.Data.TryGetValue("extraInfo", out String extraInfo);
PushNotificationModel push = new PushNotificationModel {
Title = hasTitle ? title : String.Empty,
Body = hasBody ? body : String.Empty,
Area = hasArea ? area : String.Empty,
ExtraInfo = hasExtraInfo ? extraInfo : String.Empty
};
SendNotification(push);
}
/// <summary>
/// Handles the notification to ensure the Notification manager is updated to alert the user
/// </summary>
private void SendNotification(PushNotificationModel push) {
// Create relevant non-repeatable Id to allow multiple notifications to be displayed in the Notification Manager
Int32 notificationId = Int32.Parse(DateTime.Now.ToString("MMddHHmmsss"));
Intent intent = new Intent(this, typeof(MainActivity));
intent.AddFlags(ActivityFlags.ClearTop | ActivityFlags.SingleTop);
intent.PutExtra("Area", push.Area);
intent.PutExtra("ExtraInfo", push.ExtraInfo);
PendingIntent pendingIntent = PendingIntent.GetActivity(this, notificationId, intent, PendingIntentFlags.UpdateCurrent);
notificationManager = (NotificationManager)GetSystemService(Context.NotificationService);
// Creates Notification Channel for Android devices running Oreo (8.0.0) or later
if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.O) {
NotificationChannel notificationChannel = new NotificationChannel(NotificationChannelId, NotificationChannelName, NotificationImportance.High) {
Description = NotificationChannelDescription
};
notificationManager.CreateNotificationChannel(notificationChannel);
}
// Builds notification for Notification Manager
Notification notification = new NotificationCompat.Builder(this, NotificationChannelId)
.SetSmallIcon(Resource.Drawable.ic_launcher)
.SetContentTitle(push.Title)
.SetContentText(push.Body)
.SetContentIntent(pendingIntent)
.SetAutoCancel(true)
.SetShowWhen(false)
.Build();
notificationManager.Notify(notificationId, notification);
}
}
}
Then finally my Firebase class where I use OnNewToken() to register to Azure with, OnMessageReceived() is overridden so I can handle a push notification being received and then SendNotification() which is being used to build and show the notification.
Any and all help will be highly appreciated!
