Develop Reference

Adding push notifications to a group when their count is more than one

Currently I have created group key for my android app so that the push notifications can be grouped together. My minimum target api level is 24 so I do not need to create any Summary Notification. What I am doing is something like this:
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, channelID)
.setSmallIcon(R.drawable.applogo)
.setContentTitle(sourceName)
.setContentText(messageTitle)
.setPriority(NotificationCompat.PRIORITY_HIGH)
.setSound(defaultSoundUri)
.setAutoCancel(true)
.setContentIntent(contentIntent)
.setGroup(GROUPID)
Thus I am creating the NotificationCompat Builder. The problem what I am facing is Notifications are being grouped together after the 4th one. The first three notifications are being displayed separately in the notification tray. When the fourth one is coming, they are grouped together. What I want to know is that is this the default behavior and if so then how can I change it like notifications will be grouped together when the 2nd one comes?

Notifications will be grouped after 4, this is the default behaviour since 24. And to trigger group notification less than 4 you need to create group summary notification.

Foreground Service's Notification Only says "xxx is running ... Tap for more information..."

I wanted to implement a foreground service with an ongoing notification. So far I just want some proper title and some text, but even that doesn't work. Android only shows
"AppXXX is running
Tap for more information or stop app"
The code of making the notification is as followed:
Notification notification =
new Notification.Builder(this, CHANNEL_ID)
.setContentTitle("title")
.setTicker("ticker")
.setContentIntent(pendingIntent)
.build();

setSmallIcon(...) is required for the notification to show properly. According to the anatomy of an android notification here:
Small icon: This is required and set with setSmallIcon()

How do I display hidden notifications?

I am developing a simple app that starts a service when a button is tapped... The service create an ongoing notification but I don't want it to display any icon in the status bar...
In this picture you can see WiFi ADB has a standard ongoing notification that cannot be dismissed...
Google Now (The 62 Cloudy), Automatic, and Automate do not display any icon when the notification bar is closed and they are in a separate group (under that grey line).
I looked everywhere for how to achieve that but can't find anything... Even the Android documentation which is usually quite exhaustive doesn't provide any information about it.
EDIT:
Right now this is how I display my notification:
Notification notification = new NotificationCompat.Builder(this)
.setContentTitle("Power Napp")
.setContentText("Napping...")
.setSmallIcon(R.drawable.ic_notification)
.setContentIntent(pendingIntent)
.setOngoing(true)
.build();

There's a simple trick. Add:
.setPriority(Notification.PRIORITY_MIN)
And the notification won't show the icon in the status bar.
http://developer.android.com/reference/android/app/Notification.html#PRIORITY_MIN
isn't very clear about this but it's documented here:
http://developer.android.com/design/patterns/notifications.html#correctly_set_and_manage_notification_priority

How to show Android Notifications on screen as well as status bar icon?

I feel like this should be trivial but I can't seem to make a notification show up on the phone's screen - it only shows up in the status bar at the top.
For an example of what I want to do, here's how Facebook Messenger shows up on the screen when you receive a message.
Whenever I send a notification, all it does is show the little icon in the status bar - even if I set the priority to PRIORITY_MAX. Is there another setting I need to do to make it show on screen instead of just status bar?
The Notification display code:
PendingIntent contentIntent = PendingIntent.getActivity(context, nextId++, intent, PendingIntent.FLAG_CANCEL_CURRENT);
Notification.Builder builder = new Notification.Builder(context)
.setContentTitle(title)
.setContentText(description)
.setContentIntent(contentIntent)
.setSmallIcon(R.drawable.ic_stat_notification)
.setLargeIcon(largeIcon)
.setPriority(Notification.PRIORITY_DEFAULT)
.setAutoCancel(true)
.setDefaults(Notification.DEFAULT_ALL);
if (android.os.Build.VERSION.SDK_INT >= 21) {
builder.setColor(context.getResources().getColor(R.color.orange_500))
.setVisibility(Notification.VISIBILITY_PUBLIC);
}
Notification notification = builder.build();
notificationManager.notify(id, notification);

All things considered, it's a really good idea to use NotificationCompat.Builder over Notification.Builder, let alone creating a Notification manually. It gives you nice backwards compatibility with graceful degradation (all the way back to API Level 4, otherwise known as "gadzooks, that's old"). AFAIK, it's the only way to get some of the Android Wear stuff going, when used in concert with NotificationManagerCompat. And, in this case, it seems to be happier with the newer Android 5.0+ features.
In this case, setPriority(NotificationCompat.PRIORITY_HIGH) on a NotificationCompat.Builder, used with NotificationManagerCompat, will give you the heads-up notification on Android 5.0+.

Another point, make sure the 'importance' of the notification channel you have set up for your notification is set to NotificationManager.IMPORTANCE_HIGH.
This configures how visually intrusive notifications posted to this channel are and 'high' will allow it to peek. If you have this set to NotificationManager.IMPORTANCE_DEFAULT then it won't!
Bear in mind when configuring a notification channel, once the code has ran on your device, you won't be able to alter this again. So if you need to change the importance you will need to uninstall the app and then re-run and you should see the notification on your screen!

Android: How can I put my notification on top of notification area?

I'm trying to put my notification on top of notification area.
A solution is to set the parameter "when" to my notification object with a future time like:
notification.when = System.currentTimeMills()*2;
The code that I'm using in this:
long timeNotification = System.currentTimeMillis()*2;
Notification notification = new Notification(statusIcon,c.getResources().getString(R.string.app_name),timeNotification);
notification.flags = Notification.FLAG_ONGOING_EVENT | Notification.FLAG_NO_CLEAR;
notification.when = timeNotification;
notification.priority = Notification.PRIORITY_MAX;
but some apps (like Facebook) are able to put a simple notification with their current time over mine.
If I refresh my notification it remains under these ones.
What parameters I have to set to put my Notification to the top of the notifications area?

You should do this. Other answers seem outdated.
NotificationCompat.Builder mBuilder =
(NotificationCompat.Builder) new NotificationCompat.Builder(context)
.setSmallIcon(R.drawable.some_small_icon)
.setContentTitle("Title")
.setContentText("This is a test notification with MAX priority")
.setPriority(Notification.PRIORITY_MAX);
setPriority(Notification.PRIORITY_MAX) is important. It can also be replaced with any of the following as per requirement.
Different Priority Levels Info:
PRIORITY_MAX --
Use for critical and urgent notifications that alert the user to a condition that is time-critical or needs to be resolved before they can continue with a particular task.
PRIORITY_HIGH --
Use primarily for important communication, such as message or chat events with content that is particularly interesting for the user. High-priority notifications trigger the heads-up notification display.
PRIORITY_DEFAULT --
Use for all notifications that don't fall into any of the other priorities described here.
PRIORITY_LOW --
Use for notifications that you want the user to be informed about, but that are less urgent. Low-priority notifications tend to show up at the bottom of the list, which makes them a good choice for things like public or undirected social updates: The user has asked to be notified about them, but these notifications should never take precedence over urgent or direct communication.
PRIORITY_MIN --
Use for contextual or background information such as weather information or contextual location information. Minimum-priority notifications do not appear in the status bar. The user discovers them on expanding the notification shade.
For more details check the following link:
http://developer.android.com/design/patterns/notifications.html#correctly_set_and_manage_notification_priority

You can make your notification Ongoing, when it will appear higher then other usual notification. But in this case user would not be able to clear it manually.
In order to do this set flags to your Notification object:
notif.flags = Notification.FLAG_ONGOING_EVENT | Notification.FLAG_NO_CLEAR

Try setting priority of the notification to high
documentation > Notification Priority
Also check this question may it could help you Pin Notification to top of notification area

Please note that if you want a "heads-up" notification i.e., one that displays over the top of the current user window you must have the following set in your builder:
setDefaults(NotificationCompat.DEFAULT_VIBRATE)
The reference is in the javadoc:
A notification that vibrates is more likely to be presented as a heads-up notification, on some platforms.
Complete example for a heads-up notification:
NotificationCompat.Builder mBuilder =
new NotificationCompat.Builder(context)
.setSmallIcon(R.drawable.some_small_icon)
.setContentTitle("Title")
.setContentText("This is a test notification with MAX priority")
.setPriority(Notification.PRIORITY_MAX)
.setDefaults(NotificationCompat.DEFAULT_VIBRATE);