Develop Reference

Android notification append content on update

I have made an android app (Android Studio / Java) that checks a website for content and stores it in an sqlite DB. If new content is fetched that is not stored in DB, it shows a notification with the new content for user to notice.
That's working fine, although if user does not read/open/dismiss that notification, the next notification will update current one and replace its content with new data. This is wanted behavior, because I don't want the user to receive many notifications for the same thing, so I'm using the same notification id.
This introduces a problem though, if user checks the notification now, he will see the second fetched data, but won't be aware of the existence of the first fetched data.
So, what I'm trying to do is to append to the notification's content, so that both first and second fetched data are shown.
I tried the "inboxStyle" notifications that allow for new lines to be added, but it seems to be working only for setting many lines at the time notification is created and not for appending lines to an existing notifications.
I know that I can do that by storing what user has seen and what not, whether a notification was opened, etc, but this seems too much hassle for a simple thing, there must be an easier way to achieve it.
The expected behavior would be to either be able to append the message of existing notifications, or be able to fetch the message of an existing notification (by id) and then manually append to it and push the updated notification.
If that's not clear enough, the expected outcome is:
Issue the first notification with message "Test message 1"
Issue second notification using the same notification-id with message "Test message 2" that would NOT overwrite "Test message 1" but rather keep that message and append to it, so that the notification's message would now be "Test message 1 {newline-here} Test message 2" (or even better reversed so that the last message is shown on top).
Thank you in advance!

I was looking for a solution myself. I managed to do something that works but I'm quite sure there are other elegant solutions : I'm checking whether or not similar notification has been displayed. If so, I get the previous content and append it to the new notification content before publishing.
First, make sure that the notifications you want to assemble have the same uniqueID
This way, when you receive your 2nd, 3rd notification, you can easily match the one you are creating with the ones already displayed.
Note : This code works only on API 23 and higher.
String message = null;
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
StatusBarNotification[] notifications = mNotificationManager.getActiveNotifications();
for (StatusBarNotification notification: notifications) {
if (notification.getId() == uniqueID) {
// You have a match
Bundle extras = notification.getNotification().extras;
message = extras.getCharSequence(Notification.EXTRA_TEXT).toString();
break;
}
}
}
The easy part : Now that you have the previous notification text, you have to append it to the new notification text before publishing
String newMessage = message + remoteMessage.getData.get("text");
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(getApplicationContext(),
channelID)
.setStyle(new NotificationCompat.BigTextStyle().bigText(newMessage))
.setContentTitle("Title")
.setContentText(notification.getMessage())
.setAutoCancel(true);

How to collapse multiple notifications into a single one using Firebase?

I have function in Firebase Cloud Functions which is used to send notifications to specific users within my app and has as the notificationContent the following code:
const notificationContent = {
notification: {
title: "My Notification Title",
body: "My Notification Body",
icon: "default",
sound : "default"
}
};
I have tried to use collapse_key: "unique_key" but it has no effect. I read the has an effect only when the device is offline. I also have used a tag: "unique" but every time a new notification arrives, it will override the oldest one.
I there any way in which I can achieve this with Firebase? If I receive more then one notification, to be grouped in a single one?
Thanks in advance!

If you want to use more customizable and advanced notification features.
You should only send FCM with data payload, and create notification at android client side.
Remember that if you send FCM with notification payload or notification + data payload, the notification will be created by android core system and BroadcastReceiver's onReceive method won't being called if your app is on background.
If you send FCM with data payload, it will call onReceive all the time, so you can produce custom notification manually at android client side. (most app uses latter method.)
I hope this link would be helpful.

I had this same confusion and realized I misunderstood what collapseKey and tag are for.
collapseKey will limit the number of notifications a client receives while they're offline, tag is what will stack notifications together in the drawer.
So for a typical cloud function, it should look like this:
const notification = {
notification: {
'title': 'Interesting title',
'body': 'Hello, world'
},
'data': {
'whatever': whatever,
},
'android':{
'collapseKey': collapseKey,
'priority': 'high',
'notification': {
'tag': tag,
}
},
'token': fcmToken
};
admin.messaging().send(notification)
Note that the "tag" parameter sits inside of the android notification, not the top-level notification.

The easiest and most flexible solution is to extend the FirebaseMessagingService and handle the notification yourself. But first instead of using notification on your notificationContent in your cloud function, you have to change that to data so that you send a data message instead of a notification message. The difference is that the notification message will have an implicit collapse key (the package name of the app), while the data message won't have one. But the data message needs to be handled on the client or else it won't be displayed.
Here's a sample of what you'll need for your FirebaseMessagingService:
public class MyFCMService extends FirebaseMessagingService {
#Override
public void onMessageReceived(RemoteMessage remoteMessage) {
if (remoteMessage.getNotification() != null) {
//this notification was sent from the Firebase console, because in our cloud function, we are using the DATA tag, not the notification tag
//so here we have to handle the notification that was sent from the console
...
} else if (remoteMessage.getData().get(KEY) != null) {
//this data message was sent from our cloud function
//KEY is one of the keys that you are using on the cloud function
//in your example, you are using the keys: title, body, icon, sound
//display the notification to the user
...
notificationManager.notify(TAG, ID, notificationBuilder.build());
//you have to use the same TAG and the same ID on each notification if you want your 2nd notification to simply update the text of the first one, instead of showing as a new notification
}
}
}
PS. When you send a notification from your cloud function (well if you use the data tag, it's actually a data message, not a notification message), then this method will be called, regardless if the app is in the background or in the foreground. HOWEVER, when you send a notification from the firebase console, this method will be called ONLY if the app is in the foreground. If the app is in the background, the Firebase SDK will handle the notification and show it to the user. In some cases, it makes sense to show a notification only when the user is not running the app, for example if you want to advertise some new features of the app. In that case, what you can do is use a unique tag on the notification console (e.g. "display_in_foreground") and check that tag on the client. If you have set that to true, you can show the notification even to users that are currently running the app, or if it's false you can choose not to show the notification. This check will happen only if the app is in the foreground. If it's in the background, this won't be called at all and the SDK will handle to show the notification.

Creating a local notification in response to a push notification (from firebase) in cordova/ionic

I'm building an application using Ionic Framework that implements a chat function similar to good-old facebook messenger, in that i want to notify users of a chat message, but if they view it elsewhere, i want to remove the notification from their home screen.
I'm using firebase as a back-end for push notifications (though that could be changed i suppose).
I know that you can't expire a remote notification, but i've been told you can expire + remove a local notification, so my question is - can i reliably receive a remote notification, create a local one, and display that, and then in response to a notification with a scope of 'expire' or 'remove', delete a local notification so that my users don't see a duplication of information?
Most plugins tend to detect the status of the app and add a remote notification to the homescreen with the info you've pushed by default, is there a way to avoid this?
Thanks guys.
EDIT:
- Local notifications: http://ionicframework.com/docs/native/local-notifications/
- Firebase cloud messaging: https://github.com/fechanique/cordova-plugin-fcm

As far as I can tell there're no plugins which accomplish all what you need. However..
can i reliably receive a remote notification, create a local one, and display that, and then in response to a notification with a scope of 'expire' or 'remove', delete a local notification so that my users don't see a duplication of information?
Most plugins tend to detect the status of the app and add a remote notification to the homescreen with the info you've pushed by default, is there a way to avoid this?
Yes, by using silent notifications and building the local notification by yourself.
For a project I'm working in, I modified the plugin cordova-plugin-fcm to add support for (local on demand) notifications dismiss/display, send multiple notifications to the cordova app, and some PRs that are not included yet. Also I build the notification by myself, to have full control of what is displayed. You can take a look at the code to get some ideas.
In brief it works like this:
Firstly, I send a "silent" push to the app, which is not displayed by Android:
{
"content_available": true, // IMPORTANT: For Apple -> content-available: 1, for firebase -> content_available: true
"priority": "high",
"to": "/topics/all", // or to a fcm token
"data"{
"title": "My title", // this implies that you display the notification by yourself
"body": "My body", // this implies that you display the notification by yourself
"type": "NEW_USER_MESSAGE", // only relevant to this project
"userId": "1", // only relevant to this project
"timestamp", "150000000"
}
}
Note: If the payload have the "notification": {} item, Android will display it on the system tray (if the app is in background).
https://firebase.google.com/docs/cloud-messaging/concept-options#notifications_and_data_messages
Secondly, when the push arrives to the app (in onMessageReceived()), I build the local notification, assigning it a TAG and an ID. This is the way you can use to dismiss it later.
For example, you could create a local notification with the TAG "NEW_USER_MESSAGE" and ID 1 (a constant indicating a state of the message, or the user ID for example). Also, Android will replace notifications with the same TAG and ID, so this is another way to automatically replace notifications (for example if you send a generic message, like "New update available").
public static String TYPE_NEW_USER_MESSAGE = "NEW_USER_MESSAGE";
public static String TYPE_USER_LEFT_ROOM = "USER_LEFT_ROOM";
NotificationManager notificationManager =
(NotificationManager) _ctx.getSystemService(Context.NOTIFICATION_SERVICE);
// based in the type of the message you've received, you can stylize the notification
if (type.equals( TYPE_USER_LEFT_ROOM )){
notificationBuilder.setColor(Color.RED);
notificationBuilder.setLights(Color.RED, 1000, 500);
}
else if (type.equals( TYPE_NEW_USER_MESSAGE )){
notificationBuilder.setColor(Color.BLUE);
notificationBuilder.setLights(Color.BLUE, 1000, 1000);
}
Notification n = notificationBuilder.build();
notificationManager.notify(type, userId, n);
One advantage of doing it in this way, is that you have full control of the notification to be displayed, so you can stylize it like you want.
If you want to discard expired messages, you can check out the elapsed time between the sent timestamp and the current timestamp:
java.util.Date now = new java.util.Date();
java.util.Date sent_timestamp = new java.util.Date( Long.valueOf(timestamp.toString()) );
final Long elapsed_time = ((now.getTime() - sent_timestamp.getTime()) / 1000);
Log.d(TAG, "New message. sent " + elapsed_time + "s ago");
Thirdly, when the user clicks on a notification Android will launch your app, and the plugin will send the payload of the push message to the cordova view (onNotificationReceived()).
Once your app is opened and you have received the push message, you can dismiss it adding a new action to the plugin:
onNotificationReceived(data){
if (data.wasTapped === true){
if (data.type === 'NEW_USER_MESSAGE'){
FCMPlugin.dismissNotification(NEW_USER_MESSAGE, 1);
}
}
}
The Android action:
else if (action.equals( ACTION_DISMISS_NOTIFICATION )) {
cordova.getThreadPool().execute(new Runnable() {
public void run() {
try{
Log.d(TAG, "FCMPlugin dismissNotificaton: " + args.getString(0)); //tag
NotificationManager nManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
nManager.cancel(args.getString(0)/*NEW_USER_MESSAGE*/, args.getInt(1) /*1*/);
Log.d(TAG, "FCMPlugin dismissNotificaton() to remove: " + id); //tag
callbackContext.success();
}catch(Exception e){
callbackContext.error(e.getMessage());
}
}
});
https://github.com/TrustedCircles/cordova-plugin-fcm/blob/master/src/android/FCMPlugin.java#L286
And the method exposed to the cordova app:
// dismisses a notification by tag+id
FCMPlugin.prototype.dismissNotification = function( tag, userId, success, error ){
exec(success, error, "FCMPlugin", 'dismissNotification', [tag, userId]);
}
https://github.com/TrustedCircles/cordova-plugin-fcm/blob/master/www/FCMPlugin.js#L65

The only tricky bit with notifications in cordova/ionic is the JS part receiving the notification and triggering the Android code.
I used https://github.com/phonegap/phonegap-plugin-push library and its pretty straight forward.
There is a callback when notifications are received in JS(Cordova/Ionic), use this to render you notifications locally in Android.
P.S: Basel's answer tells you how to clear your notifications, so I decided to leave that bit out.

Unable to handle event in background push notification

I am using cordova plugin add phonegap-plugin-push plugin for push notification
In forground notification works fine.and i can handle event also.
When my app is in background then i got notification as well but on click of push notification my event is not fire.
I am using below code
$cordovaPushV5.initialize(options).then(function() {
// start listening for new notifications
$cordovaPushV5.onNotification();
// start listening for errors
$cordovaPushV5.onError();
// register to get registrationId
if (PNdeviceToken == null) //becuase registration will be done only the very first
{
$cordovaPushV5.register().then(function(registrationId) {
// save `registrationId` somewhere;
window.localStorage.setItem('PNdeviceToken', registrationId);
$rootScope.fcmToken = registrationId;
console.log(registrationId)
alert("first time registered id -- " + registrationId)
})
} else {
$rootScope.fcmToken = PNdeviceToken;
alert("already saved registered id -- " + $rootScope.fcmToken)
}
});
$rootScope.$on('$cordovaPushV5:notificationReceived', function(event, data) {
console.log(event)
console.log(data)
})
When i tap on background push notiction then $cordovaPushV5:notificationReceived event not fire, How can I solve this problem?
How can i handle background push notification event?

I had the Same issue and got it resolved it after 2 days of research.
Handling the notification events is same whether the app is in foreground or background.
We have to set "content-available" : "1" in the data field while pushing notifications. Else it wont call notificationReceived event if app is in background.
Also note this is not possible as of now through Google Firebase Console.
We have to send our custom payload messages (data or notification or both) seperately using any one of the firebase servers.
Detailed info can be found on the plugin's GitHub Docs Page on background notifications.
Quoting from there -
On Android if you want your on('notification') event handler* to be called when your app is in the background it is relatively simple.
First the JSON you send from GCM will need to include "content-available": "1". This will tell the push plugin to call your on('notification') event handler* no matter what other data is in the push notification.
*on('notification') event handler = $cordovaPushV5:notificationReceived event in your case.
See this answer for sending custom payload messages using PHP and NodeJS

Showing Different Notification on Android Device and Pebble

When I use WhatsApp or Telegram and receive N messages, the notification on Android will show "N new messages" (and it can be expanded).
Telegram shows notification with contentText "7 new messages" on Android. I have achieved this successfully.
However, on my Pebble Time, the last notification is the string of the last message, not "7 new messages".
On Pebble, it shows the 7th (last) message (the censored part is phone number). This is what I want.
I am trying to develop similar feature but have not succeeded. The notification on my Android displays correctly ("N new messages") but on Pebble Time, it's identical (also "N new messages", I want it to be the Nth message).
My app on Pebble. This is NOT what I want.
I have tried to call .notify twice (one contains "N new messages" and the other contains last message) and immediately .cancel the latter but Pebble Time only shows the first one.
If I don't call .cancel on the second notification, my Pebble will show what I want BUT there will be 2 notifications on both Android and Pebble (which I don't want).
How do I achieve similar feature like WhatsApp and Telegram?
Update:
This is the snippet I use (I have used different notification ID)
NotificationCompat.Builder nb = new NotificationCompat.Builder();
...
nb.setContentText("2 new messages");
notificationManager.notify(1, nb.build());
nb.setContentText("B");
notificationManager.notify(2, nb.build());
notificationManager.cancel(2);

Because you use same id for two notification item. you can try with different id for each show notification item.
From Android docs: https://developer.android.com/reference/android/app/NotificationManager.html#notify(int, android.app.Notification)
id: An identifier for this notification unique within your
application.