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Retrieve message from a notification push

This push notification is used to notify when a new chat message is available. I want to do like Instagram, that is to say, the message into this notification is updated at each new income message received, until the user open the chat.
So, how can I retrieve the message for this specific notification? Is it possible, or I have to save (in cache) the latest messages... ?
Thank you very much

I suggest saving messages in the database, and then in the function that sends notifications, get messages (probably recent unread ones - I don't know what your logic looks like in this case).
If there are more than one, use InboxStyle():
val otherMessagesToShow = getMostRecentUnreadMessages()
if(otherMessagesToShow.size > 1) {
val style = NotificationCompat.InboxStyle()
otherMessagesToShow.forEach { style.addLine(it) }
builder.setStyle(style)
builder.setNumber(otherMessagesToShow.size)
}
Finally, update the existing one (passing the same notificationID):
notificationManager.notify(notificationId, builder.build())

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);

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.

Notification with setGroupSummary(true) is not visible in Android N

Tried to show 3 notification in cluster format. As per the doc, I added the setGroupSummary(true) property for the first notification.But in the result i have got only two notification. The notification which is added the GroupSummary property is not visible.
NotificationCompat.Builder firstNotification = createNotification(context,"1.Message","Here you go 1");
firstNotification .setGroupSummary(true);
firstNotification .setGroup("KEY_NOTIFICATION_GROUP");
NotificationCompat.Builder secondNotifi = createNotification(context,"2.Message","Here you go 2");
secondNotifi .setGroup("KEY_NOTIFICATION_GROUP");
NotificationCompat.Builder thirdNotifi= createNotification(context,"3.Message","Here you go 3");
thirdNotifi.setGroup("KEY_NOTIFICATION_GROUP");
Here the notification trigger,
notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(0,firstNotification .build());
notificationManager.notify(1,secondNotifi .build());
notificationManager.notify(2,thirdNotifi.build());
And the result is,
I want to show all three notification in the cluster format without missing.
Any help will be really appreciated.

You should check the following answer :
setgroup() in notification not working
You have to create a separate group notification and set the group summary flag true only for that, and that becomes the parent notification that bundles other notifications with the same group key within itself.

setGroupSummary's purpose is to support API levels below Nougat. On Android 7.0 and higher, it shows a normal group and just uses the on click behavior (setContentIntent) and details like the summary text of the summary notification.
On Android 7.0 and lower, it shows your summary notification as a replacement for all the other notifications the group contains.

Android 7 makes a decision regarding summary notification is shown by itself. So, you want see it unless system decides that it needs to be displayed.
Solution: create a dedicated summary notification.

Android push notification opening a custom page

my question for you is the following: I have a web app written in HTML5, wrapped as a native Android app in order to use Google Push Notifications. Because my app is using many notifications for different reasons, I want to be able to say each time a notification is received, which page to be open, like adding a 'href' in the notification intent. Is this possible?
If I wasn't clear enough please let me know.
Thanks

You can define your own notification message content. The Message builder from Google supports key value pairs to be set by the sender of the notification.
See http://developer.android.com/reference/com/google/android/gcm/server/Message.html
Example:
Message message = new Message.Builder()
.addData("link1", "http://mypage1.com")
.addData("link2", "http://mypage2.com")
.build();

When you create the notification, use setContentIntent() to attach an Intent that has been constructed to visit the right webpage:
// assuming <this> is an Activity or other Context
Intent urlIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(yourUrl));
PendingIntent urlPendingIntent = PendingIntent.getActivity(this, 0 urlIntent, 0);
Notification.Builder b = new Notification.Builder(this)
.setSmallIcon(...).setContentTitle(...).setContentText(...) // etc.
.setContentIntent(urlPendingIntent);
NotificationManager noMan
= (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
noMan.notify(ID, b.build());
If you expect to have more than one of these in the notification panel at a time:
Reconsider. It's spammy to post more than one notification.
If you must, you'll need a separate ID (or separate tag) for each.