Android Notifications using Cordova and Ionic

So you want to add push notifications to your Cordova/Android/Ionic app? I’ll walk through it. Most of this entry applies to Cordova and Android, in case you’ve made the mistake of NOT using Ionic…

Basic Info

Android notifications work through Google GCM (Google Cloud Messaging). You can read the details at http://developer.android.com/google/gcm/index.html, but here’s the summary:

Here’s the narrative version:  When your application starts up, the Android device registers with GCM server, which responds with a Registration ID.   The device then sends the registration ID to our Message Server, which stores it for future use.  Other information, such as the user’s name or location, can be sent for message targeting.

When we want to send out a notification, our Message Server sends the text to the GCM server, along with the registration ID and the API .  The GCM server relays info to the device.

The GCM Server

Setting up your Google GCM server should be a fairly quick process. It’s a simple mechanism from our perspective, but does a lot of the heavy lifting for us. Follow these directions to get it running: http://developer.android.com/google/gcm/gs.html. Be sure to make note of your GCM Project ID, and your API Key. The Project ID will go into your Android app configuration, for registration. The API Key is used to send notifications.

The Notification Server

There are any number of ways to do this, and from what I’ve seen, folks often use custom code for this. Of coruse there are some off the shelf products. But for development, I recommend the node-gcm project https://github.com/ToothlessGear/node-gcm. It’s a super-simple way to communicate with the GCM server. First install

npm install node-gcm

Next set up a node script similar to this one:

var gcm = require('node-gcm');
var message = new gcm.Message();

//API Server Key
var sender = new gcm.Sender('INSERT_YOUR_API_SENDER_KEY_HERE');
var registrationIds = [];

// Value the payload data to send...
message.addData('message', "Hello Cordova!");
message.addData('title','Push Notification Sample' );
message.addData('msgcnt','2'); // Shows up in the notification in the status bar
message.addData('soundname','beep.wav'); //Sound to play upon notification receipt - put in the www folder in app
message.collapseKey = 'demo';
message.delayWhileIdle = true; //Default is false
message.timeToLive = 3000;// Duration in seconds to hold in GCM and retry before timing out. Default 4 weeks (2,419,200 seconds) if not specified.

// At least one reg id required
registrationIds.push('THIS_IS_THE_REGISTRATION_ID_THAT_WAS_GENERATED_BY_GCM');

/**
 * Parameters: message-literal, registrationIds-array, No. of retries, callback-function
 */
sender.send(message, registrationIds, 4, function (err, result) {
    console.log(result);
});

The Android App

As you know by now, you need a plugin to do just about anything in Cordova. So install the PushPlugin https://github.com/phonegap-build/PushPlugin. This should be the only plugin you need
for both Android and iOS. You might want to scan the instructions, but (as of now) they are both overly complicated and incomplete. For starters, you don’t need PlugMan to install. Just use:

cordova plugin add https://github.com/phonegap-build/PushPlugin.git

The coding was a little bit tricky, but I finally managed a functional script for Ionic notifications. See inline comments for more information on what’s going on here:

 //factory for processing push notifications.
angular.module('pushnotification', [])
   .factory('PushProcessingService', function() {
        function onDeviceReady() {
            console.info('NOTIFY  Device is ready.  Registering with GCM server');
            //register with google GCM server
            var pushNotification = window.plugins.pushNotification;
            pushNotification.register(gcmSuccessHandler, gcmErrorHandler, {"senderID":gcmAppID,"ecb":"onNotificationGCM"});
        }
        function gcmSuccessHandler(result) {
            console.info('NOTIFY  pushNotification.register succeeded.  Result = '+result)
        }
        function gcmErrorHandler(error) {
            console.error('NOTIFY  '+error);
        }
        return {
            initialize : function () {
                console.info('NOTIFY  initializing');
                document.addEventListener('deviceready', onDeviceReady, false);
            },
            registerID : function (id) {
                //Insert code here to store the user's ID on your notification server.
                //You'll probably have a web service (wrapped in an Angular service of course) set up for this.
                //For example:
                MyService.registerNotificationID(id).then(function(response){
                    if (response.data.Result) {
                        console.info('NOTIFY  Registration succeeded');
                    } else {
                        console.error('NOTIFY  Registration failed');
                    }
                });
            },
            //unregister can be called from a settings area.
            unregister : function () {
                console.info('unregister')
                var push = window.plugins.pushNotification;
                if (push) {
                    push.unregister(function () {
                        console.info('unregister success')
                    });
                }
            }
        }
    });

// ALL GCM notifications come through here.
function onNotificationGCM(e) {
    console.log('EVENT -> RECEIVED:' + e.event + '');
    switch( e.event )
    {
        case 'registered':
            if ( e.regid.length > 0 )
            {
                console.log('REGISTERED with GCM Server -> REGID:' + e.regid + "");

                //call back to web service in Angular.
                //This works for me because in my code I have a factory called
                //      PushProcessingService with method registerID
                var elem = angular.element(document.querySelector('[ng-app]'));
                var injector = elem.injector();
                var myService = injector.get('PushProcessingService');
                myService.registerID(e.regid);
            }
            break;

        case 'message':
            // if this flag is set, this notification happened while we were in the foreground.
            // you might want to play a sound to get the user's attention, throw up a dialog, etc.
            if (e.foreground)
            {
                //we're using the app when a message is received.
                console.log('--INLINE NOTIFICATION--' + '');

                // if the notification contains a soundname, play it.
                //var my_media = new Media("/android_asset/www/"+e.soundname);
                //my_media.play();
                alert(e.payload.message);
            }
            else
            {
                // otherwise we were launched because the user touched a notification in the notification tray.
                if (e.coldstart)
                    console.log('--COLDSTART NOTIFICATION--' + '');
                else
                    console.log('--BACKGROUND NOTIFICATION--' + '');

                // direct user here:
                window.location = "#/tab/featured";
            }

            console.log('MESSAGE -> MSG: ' + e.payload.message + '');
            console.log('MESSAGE: '+ JSON.stringify(e.payload));
            break;

        case 'error':
            console.log('ERROR -> MSG:' + e.msg + '');
            break;

        default:
            console.log('EVENT -> Unknown, an event was received and we do not know what it is');
            break;
    }
}

Call it from here:

app.run(function(PushProcessingService) {
   //run once for the app
   PushProcessingService.initialize();
});

Hopefully this is helpful to someone!

Thanks to these folks (and others) who put together helpful blogs on this topic:

• http://devgirl.org/2012/10/25/tutorial-android-push-notifications-with-phonegap/
• http://www.androidhive.info/2012/10/android-push-notifications-using-google-cloud-messaging-gcm-php-and-mysql