How to display multiple notification as a group?

Question

here is my code for notification. it generate a new notification each time

Random random = new Random();
int m = random.nextInt(9999 - 1000);    
Notific         


        

Answer 1

Use below give code for your notification manager and increment the count whenever a new notification received.

mNotificationManager.notify(count, mBuilder.build());

Answer 2

When creating notifications for a handheld device, you should always aggregate similar notifications into a single summary notification.

Check this it shows how to build stack notification.

private void sendStackNotificationIfNeeded(RemoteNotification remoteNotification) {
    // only run this code if the device is running 23 or better
    if (Build.VERSION.SDK_INT >= 23) {
        ArrayList<StatusBarNotification> groupedNotifications = new ArrayList<>();

        // step through all the active StatusBarNotifications and
        for (StatusBarNotification sbn : getNotificationManagerService().getActiveNotifications()) {
            // add any previously sent notifications with a group that matches our RemoteNotification
            // and exclude any previously sent stack notifications
            if (remoteNotification.getUserNotificationGroup() != null &&
                    remoteNotification.getUserNotificationGroup().equals(sbn.getNotification().getGroup()) &&
                    sbn.getId() != RemoteNotification.TYPE_STACK) {
                groupedNotifications.add(sbn);
            }
        }

        // since we assume the most recent notification was delivered just prior to calling this method,
        // we check that previous notifications in the group include at least 2 notifications
        if (groupedNotifications.size() > 1) {
            NotificationCompat.Builder builder = new NotificationCompat.Builder(this);

            // use convenience methods on our RemoteNotification wrapper to create a title
            builder.setContentTitle(String.format("%s: %s", remoteNotification.getAppName(), remoteNotification.getErrorName()))
                    .setContentText(String.format("%d new activities", groupedNotifications.size()));

            // for every previously sent notification that met our above requirements,
            // add a new line containing its title to the inbox style notification extender
            NotificationCompat.InboxStyle inbox = new NotificationCompat.InboxStyle();
            {
                for (StatusBarNotification activeSbn : groupedNotifications) {
                    String stackNotificationLine = (String)activeSbn.getNotification().extras.get(NotificationCompat.EXTRA_TITLE);
                    if (stackNotificationLine != null) {
                        inbox.addLine(stackNotificationLine);
                    }
                }

                // the summary text will appear at the bottom of the expanded stack notification
                // we just display the same thing from above (don't forget to use string
                // resource formats!)
                inbox.setSummaryText(String.format("%d new activities", groupedNotifications.size()));
            }
            builder.setStyle(inbox);

            // make sure that our group is set the same as our most recent RemoteNotification
            // and choose to make it the group summary.
            // when this option is set to true, all previously sent/active notifications
            // in the same group will be hidden in favor of the notifcation we are creating
            builder.setGroup(remoteNotification.getUserNotificationGroup())
                .setGroupSummary(true);

            // if the user taps the notification, it should disappear after firing its content intent
            // and we set the priority to high to avoid Doze from delaying our notifications
            builder.setAutoCancel(true)
                .setPriority(NotificationCompat.PRIORITY_HIGH);

            // create a unique PendingIntent using an integer request code.
            final int requestCode = (int)System.currentTimeMillis() / 1000;
            builder.setContentIntent(PendingIntent.getActivity(this, requestCode, DetailActivity.createIntent(this), PendingIntent.FLAG_ONE_SHOT));

            Notification stackNotification = builder.build();
            stackNotification.defaults = Notification.DEFAULT_ALL;

            // finally, deliver the notification using the group identifier as the Tag
            // and the TYPE_STACK which will cause any previously sent stack notifications
            // for this group to be updated with the contents of this built summary notification
            getNotificationManagerService().notify(remoteNotification.getUserNotificationGroup(), RemoteNotification.TYPE_STACK, stackNotification);
        }
    }
}

Answer 3

From https://developer.android.com/training/notify-user/group.

    String GROUP_KEY_WORK_EMAIL = "com.android.example.WORK_EMAIL";

Notification newMessageNotification = new NotificationCompat.Builder(MainActivity.this, CHANNEL_ID)
        .setSmallIcon(R.drawable.new_mail)
        .setContentTitle(emailObject.getSenderName())
        .setContentText(emailObject.getSubject())
        .setLargeIcon(emailObject.getSenderAvatar())
        .setGroup(GROUP_KEY_WORK_EMAIL)
        .build();
By default, notifications are sorted according to when they were posted, but you can change order by calling setSortKey().

If alerts for a notification's group should be handled by a different notification, call setGroupAlertBehavior(). For example, if you want only the summary of your group to make noise, all children in the group should have the group alert behavior GROUP_ALERT_SUMMARY. The other options are GROUP_ALERT_ALL and GROUP_ALERT_CHILDREN.

Set a group summary
On Android 7.0 (API level 24) and higher, the system automatically builds a summary for your group using snippets of text from each notification. The user can expand this notification to see each separate notification, as shown in figure 1. To support older versions, which cannot show a nested group of notifications, you must create an extra notification that acts as the summary. This appears as the only notification and the system hides all the others. So this summary should include a snippet from all the other notifications, which the user can tap to open your app.

Note: The behavior of the group summary may vary on some device types such as wearables. To ensure the best experience on all devices and versions, always include a group summary when you create a group.
To add a group summary, proceed as follows:

Create a new notification with a description of the group—often best done with the inbox-style notification.
Add the summary notification to the group by calling setGroup().
Specify that it should be used as the group summary by calling setGroupSummary(true).
For example:

//use constant ID for notification used as group summary
int SUMMARY_ID = 0;
String GROUP_KEY_WORK_EMAIL = "com.android.example.WORK_EMAIL";

Notification newMessageNotification1 =
    new NotificationCompat.Builder(MainActivity.this, CHANNEL_ID)
        .setSmallIcon(R.drawable.ic_notify_email_status)
        .setContentTitle(emailObject1.getSummary())
        .setContentText("You will not believe...")
        .setGroup(GROUP_KEY_WORK_EMAIL)
        .build();

Notification newMessageNotification2 =
    new NotificationCompat.Builder(MainActivity.this, CHANNEL_ID)
        .setSmallIcon(R.drawable.ic_notify_email_status)
        .setContentTitle(emailObject2.getSummary())
        .setContentText("Please join us to celebrate the...")
        .setGroup(GROUP_KEY_WORK_EMAIL)
        .build();

Notification summaryNotification =
    new NotificationCompat.Builder(MainActivity.this, CHANNEL_ID)
        .setContentTitle(emailObject.getSummary())
        //set content text to support devices running API level < 24
        .setContentText("Two new messages")
        .setSmallIcon(R.drawable.ic_notify_summary_status)
        //build summary info into InboxStyle template
        .setStyle(new NotificationCompat.InboxStyle()
                .addLine("Alex Faarborg  Check this out")
                .addLine("Jeff Chang    Launch Party")
                .setBigContentTitle("2 new messages")
                .setSummaryText("janedoe@example.com"))
        //specify which group this notification belongs to
        .setGroup(GROUP_KEY_WORK_EMAIL)
        //set this notification as the summary for the group
        .setGroupSummary(true)
        .build();

NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
notificationManager.notify(emailNotificationId1, newMessageNotification1);
notificationManager.notify(emailNotificationId2, newMessageNotification2);
notificationManager.notify(SUMMARY_ID, summaryNotification);

The summary notification ID should stay the same so that it is only posted once, and so you can update it later if the summary information changes (subsequent additions to the group should result in updating the existing summary).

Answer 4

It will generate notification with multiple messages like Gmail

NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this)
                    .setSmallIcon(R.drawable.quemark1)
                    .setContentTitle("Title")
                    .setContentText("New Message received");
            NotificationCompat.InboxStyle inboxStyle =
                    new NotificationCompat.InboxStyle();

            inboxStyle.setBigContentTitle("doUdo");

           // Add your All messages here or use Loop to generate messages

                inboxStyle.addLine("Messgare 1");
                inboxStyle.addLine("Messgare 2");
                          .
                          .
                inboxStyle.addLine("Messgare n");


            mBuilder.setStyle(inboxStyle);
            TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);

            stackBuilder.addNextIntent(intent);

            PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent,
                    PendingIntent.FLAG_UPDATE_CURRENT);

            mBuilder.setContentIntent(pIntent);

            NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
            mBuilder.setDefaults(Notification.DEFAULT_SOUND | Notification.DEFAULT_VIBRATE);
            mBuilder.setAutoCancel(true);
            mNotificationManager.notify(0, mBuilder.build());