Xamarin.Forms
Pushmeldingen

Opmerkingen

Pushmeldingen voor iOS met Azure

Om de registratie voor pushmeldingen te starten, moet u de onderstaande code uitvoeren.

// registers for push
var settings = UIUserNotificationSettings.GetSettingsForTypes(
    UIUserNotificationType.Alert
    | UIUserNotificationType.Badge
    | UIUserNotificationType.Sound,
    new NSSet());

UIApplication.SharedApplication.RegisterUserNotificationSettings(settings);
UIApplication.SharedApplication.RegisterForRemoteNotifications();

Deze code kan direct worden uitgevoerd wanneer de app opstart in de FinishedLaunching in het bestand AppDelegate.cs . Of u kunt dit doen wanneer een gebruiker besluit dat hij pushmeldingen wil inschakelen.

Als deze code wordt uitgevoerd, wordt een waarschuwing weergegeven om de gebruiker te vragen of deze accepteert dat de app meldingen kan verzenden. Dus implementeer ook een scenario waarin de gebruiker dat ontkent!

Dit zijn de evenementen die moeten worden geïmplementeerd voor het implementeren van pushmeldingen op iOS. Je kunt ze vinden in het bestand AppDelegate.cs .

// We've successfully registered with the Apple notification service, or in our case Azure
public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
{
   // Modify device token for compatibility Azure
    var token = deviceToken.Description;
    token = token.Trim('<', '>').Replace(" ", "");
    
    // You need the Settings plugin for this!
    Settings.DeviceToken = token;
    
    var hub = new SBNotificationHub("Endpoint=sb://xamarinnotifications-ns.servicebus.windows.net/;SharedAccessKeyName=DefaultListenSharedAccessSignature;SharedAccessKey=<your own key>", "xamarinnotifications");
    
    NSSet tags = null; // create tags if you want, not covered for now
    hub.RegisterNativeAsync(deviceToken, tags, (errorCallback) =>
    {
        if (errorCallback != null)
        {
            var alert = new UIAlertView("ERROR!", errorCallback.ToString(), null, "OK", null);
            alert.Show();
        }
    });
}

// We've received a notification, yay!
public override void ReceivedRemoteNotification(UIApplication application, NSDictionary userInfo)
{
    NSObject inAppMessage;

    var success = userInfo.TryGetValue(new NSString("inAppMessage"), out inAppMessage);

    if (success)
    {
        var alert = new UIAlertView("Notification!", inAppMessage.ToString(), null, "OK", null);
        alert.Show();
    }
}

// Something went wrong while registering!
public override void FailedToRegisterForRemoteNotifications(UIApplication application, NSError error)
{
   var alert = new UIAlertView("Computer says no", "Notification registration failed! Try again!", null, "OK", null);
                    
   alert.Show();
}

Wanneer een melding wordt ontvangen, ziet deze er zo uit.

Pushmeldingen voor Android met Azure

Implementatie op Android is iets meer werk en vereist dat een specifieke Service wordt geïmplementeerd.

Laten we eerst controleren of ons apparaat pushmeldingen kan ontvangen en, als dit het geval is, registreren bij Google. Dit kan met deze code in ons bestand MainActivity.cs .

protected override void OnCreate(Bundle bundle)
{
    base.OnCreate(bundle);

    global::Xamarin.Forms.Forms.Init(this, bundle);

    // Check to ensure everything's setup right for push
    GcmClient.CheckDevice(this);
    GcmClient.CheckManifest(this);
    GcmClient.Register(this, NotificationsBroadcastReceiver.SenderIDs);

    LoadApplication(new App());
}

De SenderID's zijn te vinden in de onderstaande code en is het projectnummer dat u van het Google-ontwikkelaarsdashboard krijgt om pushberichten te kunnen verzenden.

using Android.App;
using Android.Content;
using Gcm.Client;
using Java.Lang;
using System;
using WindowsAzure.Messaging;
using XamarinNotifications.Helpers;

// These attributes are to register the right permissions for our app concerning push messages
[assembly: Permission(Name = "com.versluisit.xamarinnotifications.permission.C2D_MESSAGE")]
[assembly: UsesPermission(Name = "com.versluisit.xamarinnotifications.permission.C2D_MESSAGE")]
[assembly: UsesPermission(Name = "com.google.android.c2dm.permission.RECEIVE")]

//GET_ACCOUNTS is only needed for android versions 4.0.3 and below
[assembly: UsesPermission(Name = "android.permission.GET_ACCOUNTS")]
[assembly: UsesPermission(Name = "android.permission.INTERNET")]
[assembly: UsesPermission(Name = "android.permission.WAKE_LOCK")]

namespace XamarinNotifications.Droid.PlatformSpecifics
{
    // These attributes belong to the BroadcastReceiver, they register for the right intents
    [BroadcastReceiver(Permission = Constants.PERMISSION_GCM_INTENTS)]
    [IntentFilter(new[] { Constants.INTENT_FROM_GCM_MESSAGE },
    Categories = new[] { "com.versluisit.xamarinnotifications" })]
    [IntentFilter(new[] { Constants.INTENT_FROM_GCM_REGISTRATION_CALLBACK },
    Categories = new[] { "com.versluisit.xamarinnotifications" })]
    [IntentFilter(new[] { Constants.INTENT_FROM_GCM_LIBRARY_RETRY },
    Categories = new[] { "com.versluisit.xamarinnotifications" })]

    // This is the bradcast reciever
    public class NotificationsBroadcastReceiver : GcmBroadcastReceiverBase<PushHandlerService>
    {
        // TODO add your project number here
        public static string[] SenderIDs = { "96688------" };
    }

    [Service] // Don't forget this one! This tells Xamarin that this class is a Android Service
    public class PushHandlerService : GcmServiceBase
    {
        // TODO add your own access key
        private string _connectionString = ConnectionString.CreateUsingSharedAccessKeyWithListenAccess(
            new Java.Net.URI("sb://xamarinnotifications-ns.servicebus.windows.net/"), "<your key here>");

        // TODO add your own hub name
        private string _hubName = "xamarinnotifications";

        public static string RegistrationID { get; private set; }

        public PushHandlerService() : base(NotificationsBroadcastReceiver.SenderIDs)
        {
        }

        // This is the entry point for when a notification is received
        protected override void OnMessage(Context context, Intent intent)
        {
            var title = "XamarinNotifications";

            if (intent.Extras.ContainsKey("title"))
                title = intent.Extras.GetString("title");

            var messageText = intent.Extras.GetString("message");

            if (!string.IsNullOrEmpty(messageText))
                CreateNotification(title, messageText);
        }

        // The method we use to compose our notification
        private void CreateNotification(string title, string desc)
        {
            // First we make sure our app will start when the notification is pressed
            const int pendingIntentId = 0;
            const int notificationId = 0;

            var startupIntent = new Intent(this, typeof(MainActivity));
            var stackBuilder = TaskStackBuilder.Create(this);

            stackBuilder.AddParentStack(Class.FromType(typeof(MainActivity)));
            stackBuilder.AddNextIntent(startupIntent);

            var pendingIntent =
                stackBuilder.GetPendingIntent(pendingIntentId, PendingIntentFlags.OneShot);

            // Here we start building our actual notification, this has some more
            // interesting customization options!
            var builder = new Notification.Builder(this)
                .SetContentIntent(pendingIntent)
                .SetContentTitle(title)
                .SetContentText(desc)
                .SetSmallIcon(Resource.Drawable.icon);

            // Build the notification
            var notification = builder.Build();
            notification.Flags = NotificationFlags.AutoCancel;

            // Get the notification manager
            var notificationManager =
                GetSystemService(NotificationService) as NotificationManager;

            // Publish the notification to the notification manager
            notificationManager.Notify(notificationId, notification);
        }

        // Whenever an error occurs in regard to push registering, this fires
        protected override void OnError(Context context, string errorId)
        {
            Console.Out.WriteLine(errorId);
        }

        // This handles the successful registration of our device to Google
        // We need to register with Azure here ourselves
        protected override void OnRegistered(Context context, string registrationId)
        {
            var hub = new NotificationHub(_hubName, _connectionString, context);

            Settings.DeviceToken = registrationId;

            // TODO set some tags here if you want and supply them to the Register method
            var tags = new string[] { };

            hub.Register(registrationId, tags);
        }

        // This handles when our device unregisters at Google
        // We need to unregister with Azure
        protected override void OnUnRegistered(Context context, string registrationId)
        {
            var hub = new NotificationHub(_hubName, _connectionString, context);

            hub.UnregisterAll(registrationId);
        }
    }
}

Een voorbeeldmelding op Android ziet er zo uit.

Pushmeldingen voor Windows Phone met Azure

Op Windows Phone moet zoiets als de onderstaande code worden geïmplementeerd om met pushmeldingen te kunnen werken. Dit is te vinden in het bestand App.xaml.cs

protected async override void OnLaunched(LaunchActivatedEventArgs e)
{
    var channel = await PushNotificationChannelManager.CreatePushNotificationChannelForApplicationAsync();
 
    // TODO add connection string here
    var hub = new NotificationHub("XamarinNotifications", "<connection string with listen access>");
    var result = await hub.RegisterNativeAsync(channel.Uri);
 
    // Displays the registration ID so you know it was successful
    if (result.RegistrationId != null)
    {
        Settings.DeviceToken = result.RegistrationId;
    }
 
    // The rest of the default code is here
}

Vergeet ook niet om de mogelijkheden in het bestand Package.appxmanifest in te schakelen.

Een voorbeeld van een pushmelding kan er zo uitzien: