The AWS Mobile SDK for Xamarin is now included in the AWS SDK for .NET. This guide references the archived version of the Mobile SDK for Xamarin.

Receive Push Notifications using SNS (Xamarin Android)

The tutorial explains how to send push notifications to a Xamarin Android application using Amazon Simple Notification Service (SNS) and the AWS Mobile SDK for .NET and Xamarin.

Project Setup

Prerequisites

You must complete all of the instructions on the Setting Up the AWS Mobile SDK for .NET and Xamarin before beginning this tutorial.

Set Permissions for SNS

Follow Step 2 in Setting Up the AWS Mobile SDK for .NET and Xamarin to attach the policy mentioned below to your application’s roles. This will give your application the proper permissions to access SNS:

Enable Push Notifications on Google Cloud

First, add a new Google API project:

Next, enable the Google Cloud Messaging (GCM) service for your project:

Finally, obtain an API Key:

Use Project ID to Create a Platform ARN in SNS Console

Add NuGet Package for SNS to Your Project

Follow Step 4 of the instructions in Setting Up the AWS Mobile SDK for .NET and Xamarin to add the Amazon Simple Notification Service NuGet package to your project.

Create an SNS client

var snsClient = new AmazonSimpleNotificationServiceClient(credentials, region);

Register Your Application for Remote Notifications

In order to register for remote notifications on Android, you will need to create a BroadcastReceiver which can receive Google Cloud messages. Change the package name below where prompted to do so:

[BroadcastReceiver(Permission = "com.google.android.c2dm.permission.SEND")]
[IntentFilter(new string[] {
      "com.google.android.c2dm.intent.RECEIVE"
}, Categories = new string[] {
      "com.amazonaws.sns" /* change to match your package */
})]
[IntentFilter(new string[] {
      "com.google.android.c2dm.intent.REGISTRATION"
}, Categories = new string[] {
      "com.amazonaws.sns" /* change to match your package */
})]
[IntentFilter(new string[] {
      "com.google.android.gcm.intent.RETRY"
}, Categories = new string[] {
      "com.amazonaws.sns" /* change to match your package */
})]
public class GCMBroadcastReceiver: BroadcastReceiver {
      const string TAG = "PushHandlerBroadcastReceiver";
      public override void OnReceive(Context context, Intent intent) {
              GCMIntentService.RunIntentInService(context, intent);
              SetResult(Result.Ok, null, null);
      }
}

[BroadcastReceiver]
[IntentFilter(new[] {
      Android.Content.Intent.ActionBootCompleted
})]
public class GCMBootReceiver: BroadcastReceiver {
      public override void OnReceive(Context context, Intent intent) {
              GCMIntentService.RunIntentInService(context, intent);
              SetResult(Result.Ok, null, null);
      }
}

Below is the service that receives the push notification from the BroadcastReceiver and displays the notification on the device’s notification bar:

[Service]
 public class GCMIntentService: IntentService {
  static PowerManager.WakeLock sWakeLock;
  static object LOCK = new object();

  public static void RunIntentInService(Context context, Intent intent) {
    lock(LOCK) {
      if (sWakeLock == null) {
        // This is called from BroadcastReceiver, there is no init.
        var pm = PowerManager.FromContext(context);
        sWakeLock = pm.NewWakeLock(
        WakeLockFlags.Partial, "My WakeLock Tag");
      }
    }

    sWakeLock.Acquire();
    intent.SetClass(context, typeof(GCMIntentService));
    context.StartService(intent);
  }

  protected override void OnHandleIntent(Intent intent) {
    try {
      Context context = this.ApplicationContext;
      string action = intent.Action;

      if (action.Equals("com.google.android.c2dm.intent.REGISTRATION")) {
        HandleRegistration(intent);
      } else if (action.Equals("com.google.android.c2dm.intent.RECEIVE")) {
        HandleMessage(intent);
      }
    } finally {
      lock(LOCK) {
        //Sanity check for null as this is a public method
        if (sWakeLock != null) sWakeLock.Release();
      }
    }
  }

  private void HandleRegistration(Intent intent) {
    string registrationId = intent.GetStringExtra("registration_id");
    string error = intent.GetStringExtra("error");
    string unregistration = intent.GetStringExtra("unregistered");

    if (string.IsNullOrEmpty(error)) {
      var response = await SnsClient.CreatePlatformEndpointAsync(new CreatePlatformEndpointRequest {
        Token = registrationId,
        PlatformApplicationArn = "YourPlatformArn" /* insert your platform application ARN here */
      });
    }
  }

  private void HandleMessage(Intent intent) {
    string message = string.Empty;
    Bundle extras = intent.Extras;
    if (!string.IsNullOrEmpty(extras.GetString("message"))) {
      message = extras.GetString("message");
    } else {
      message = extras.GetString("default");
    }

    Log.Info("Messages", "message received = " + message);
    ShowNotification(this, "SNS Push", message);
    //show the message

  }

  public void ShowNotification(string contentTitle,
  string contentText) {
    // Intent
    Notification.Builder builder = new Notification.Builder(this)
      .SetContentTitle(contentTitle)
      .SetContentText(contentText)
      .SetDefaults(NotificationDefaults.Sound | NotificationDefaults.Vibrate)
      .SetSmallIcon(Resource.Drawable.Icon)
      .SetSound(RingtoneManager.GetDefaultUri(RingtoneType.Notification));

    // Get the notification manager:
    NotificationManager notificationManager = this.GetSystemService(Context.NotificationService) as NotificationManager;

    notificationManager.Notify(1001, builder.Build());
  }
}

Send a Message from the SNS Console to Your Endpoint