Develop Reference

How to create a Android notification with support to older API levels (e.g. lvl 23)

Maybe this issue is way simpler than I expected it to be: I want to display a notification, created within the onCreate function of an Activity (for debugging reasons).
Android Studio 3.0.1, Api lvl 23 (to support older devices) and running on a Nexus5 device with Api lvl 27.
The Code to display a notification:
PendingIntent pi = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
Notification notification = new NotificationCompat.Builder(this)
.setTicker("SomethingTicker")
.setSmallIcon(R.drawable.someImage)
.setContentTitle("SomeTitle")
.setContentText("SomeText")
.setContentIntent(pi)
.build();
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
notificationManager.notify(001, notification);
Which shows that NotificationCompat.Builder with only the the context is deprecated. I should use a Notification Channel within the newer version.
The issue: To create and register a NotificationChannel I have to use api lvl >27.
What am I missing? And what is the best way

I want to display a notification, created within the onCreate function of an Activity.
Note that this is an odd time to display a Notification.
What am I missing?
You need code to create the NotificationChannel that will only run on Android 8.0+ devices:
NotificationManager mgr=
(NotificationManager)getSystemService(NOTIFICATION_SERVICE);
if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.O &&
mgr.getNotificationChannel(CHANNEL_WHATEVER)==null) {
mgr.createNotificationChannel(new NotificationChannel(CHANNEL_WHATEVER,
"Whatever", NotificationManager.IMPORTANCE_DEFAULT));
}
Then, for all API levels, pass in your channel identifier (here, CHANNEL_WHATEVER) to the NotificationCompat.Builder constructor. On older devices, the channel will be ignored.

Android Notification Not working on Android 6.0 (Marshmallow)

I'm implementing local notification on Android and I have the problem that they are not appearing on Android 6.0 (Samsung S7).
I was searching for solutions, but I coulnd't find anything for this problem. I have the icon in the proper res/drawable folder, also I have defined a notification title, text, ringtone (raw folder) but it's not showing up...
There is my code:
Context acontext = getApplicationContext();
PackageManager pm = acontext.getPackageManager();
Intent notificationIntent = pm.getLaunchIntentForPackage(acontext.getPackageName());
notificationIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
PendingIntent pendingIntent = PendingIntent.getActivity(acontext, 0, notificationIntent, 0);
int notification_icon = acontext.getResources().getIdentifier("icon", "drawable", acontext.getPackageName());
int notificationID = 0;
// Build notification
Notification noti = new Notification.Builder(acontext)
.setContentTitle("Title")
.setContentText("Incoming text")
.setSmallIcon(notification_icon)
.setContentIntent(pendingIntent)
.setLights(Color.RED, 1, 1)
.build();
NotificationManager notificationManager = (NotificationManager) acontext.getSystemService(Context.NOTIFICATION_SERVICE);
// hide the notification after its selected
noti.sound = Uri.parse("android.resource://" + acontext.getPackageName() + "/raw/incoming");
noti.flags |= Notification.FLAG_AUTO_CANCEL;
notificationManager.notify(notificationID, noti);
Did anyone else experience this problem? Any help would be appreciated. Thank you.

There are some changes in new notification. new NotificationCompat.Builder(this) is deprecated and need NotificationChannelfor android oreo above. You can try this solution.
NotificationCompat.Builder mBuilder =
new NotificationCompat.Builder(mContext.getApplicationContext(), "notify_001");
Intent ii = new Intent(mContext.getApplicationContext(), RootActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(mContext, 0, ii, 0);
NotificationCompat.BigTextStyle bigText = new NotificationCompat.BigTextStyle();
bigText.bigText(verseurl);
bigText.setBigContentTitle("Title");
bigText.setSummaryText("Text in detail");
mBuilder.setContentIntent(pendingIntent);
mBuilder.setSmallIcon(R.mipmap.ic_launcher_round);
mBuilder.setContentTitle("Your Title");
mBuilder.setContentText("Your text");
mBuilder.setPriority(Notification.PRIORITY_MAX);
mBuilder.setStyle(bigText);
NotificationManager mNotificationManager =
(NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationChannel channel = new NotificationChannel("notify_001",
"Channel human readable title",
NotificationManager.IMPORTANCE_DEFAULT);
mNotificationManager.createNotificationChannel(channel);
}
mNotificationManager.notify(0, mBuilder.build());

There are various layers involved in showing notifications in Android, Please first check if this works for other devices of same OS version. Normally these kind of issues are device specific not OS specific, Also check notification logs how to check notification logs in android ?
If issue is device specific, following can be handy tips:
Check notifications not blocked for your app by device settings.
Check power settings blocking non-priority notifications.
If there are notifications in logs but not showing up, there can be some issue with your internal OS settings/configs. (believe me Android is not very clean OS)
If you can, try factory resetting your device. (In my case this worked)

Google Play Services must be enabled in order to receive push notifications on your Android device. If Google Play Services are enabled and the general troubleshooting steps have not resolved the issue, it may be necessary to reset the app. To reset the app, go to Settings → Apps → PagerDuty and tap Clear Data.
For Android 6.0 and newer, make sure the app is set as a prioritized app in priority mode.
For Android 6.0 and newer, check to see if the app is being silenced by Doze mode.

Check the android version accordingly set the icon for > 6.0 and for other.For 6.0 version we need white background icon.
if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
icon = R.mipmap.your_logo_for_Lolipop;
}else{
icon = R.drawable.your_logo_for_Kitkat ;
}

Update notification to remove chronometer (KitKat)

I need to show a notification and update it over the course of its lifetime. In particular, I need to change certain flags, such as "show chronometer". For that, the documentation states that we should call NotificationManager.notify() with the same id.
So the idea is to have these methods:
private void showInitialNotification() {
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
...
mNotificationManager.notify(NOTIFICATION_ID, builder.build());
}
private void addChronometerFlag() {
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
...
builder.setUsesChronometer(true);
mNotificationManager.notify(NOTIFICATION_ID, builder.build());
}
private void removeChronometerFlag() {
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
...
builder.setUsesChronometer(false);
mNotificationManager.notify(NOTIFICATION_ID, builder.build());
}
This works perfectly OK in Android 5.1 and 6.0, but in Android 4.4 (and below, I guess?) the chronometer is not removed, although the content title, text, icon &c are updated correctly.
Any idea why?
I cannot use the same Notification.Builder object (for example as suggested in this answer) since I also need to update the actions available on the notification and there is no way to remove previously added actions to a Builder.
My use case is somewhat more complicated (it's a media player) but this is the minimum example of the bug I've been able to reproduce. It's also present, for example, in Google's UniversalMusicPlayer sample -- works fine in Lollipop, but not in KitKat.
FWIW, the full example code is here.

Android notification is not showing

I need a program that will add a notification on Android. And when someone clicks on the notification, it should lead them to my second activity.
I have established code. The notification should be working, but for some reason it is not working. The Notification isn't showing at all. I don't know what am I missing.
Code of those files:
Notification n = new Notification.Builder(this)
.setContentTitle("New mail from " + "test#gmail.com")
.setContentText("Subject")
.setContentIntent(pIntent).setAutoCancel(true)
.setStyle(new Notification.BigTextStyle().bigText(longText))
.build();
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// Hide the notification after it's selected
notificationManager.notify(0, n);

The code won't work without an icon. So, add the setSmallIcon call to the builder chain like this for it to work:
.setSmallIcon(R.drawable.icon)
Android Oreo (8.0) and above
Android 8 introduced a new requirement of setting the channelId property by using a NotificationChannel.
NotificationManager mNotificationManager;
NotificationCompat.Builder mBuilder =
new NotificationCompat.Builder(mContext.getApplicationContext(), "notify_001");
Intent ii = new Intent(mContext.getApplicationContext(), RootActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(mContext, 0, ii, 0);
NotificationCompat.BigTextStyle bigText = new NotificationCompat.BigTextStyle();
bigText.bigText(verseurl);
bigText.setBigContentTitle("Today's Bible Verse");
bigText.setSummaryText("Text in detail");
mBuilder.setContentIntent(pendingIntent);
mBuilder.setSmallIcon(R.mipmap.ic_launcher_round);
mBuilder.setContentTitle("Your Title");
mBuilder.setContentText("Your text");
mBuilder.setPriority(Notification.PRIORITY_MAX);
mBuilder.setStyle(bigText);
mNotificationManager =
(NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
// === Removed some obsoletes
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
{
String channelId = "Your_channel_id";
NotificationChannel channel = new NotificationChannel(
channelId,
"Channel human readable title",
NotificationManager.IMPORTANCE_HIGH);
mNotificationManager.createNotificationChannel(channel);
mBuilder.setChannelId(channelId);
}
mNotificationManager.notify(0, mBuilder.build());

Actually the answer by ƒernando Valle doesn't seem to be correct. Then again, your question is overly vague because you fail to mention what is wrong or isn't working.
Looking at your code I am assuming the Notification simply isn't showing.
Your notification is not showing, because you didn't provide an icon. Even though the SDK documentation doesn't mention it being required, it is in fact very much so and your Notification will not show without one.
addAction is only available since 4.1. Prior to that you would use the PendingIntent to launch an Activity. You seem to specify a PendingIntent, so your problem lies elsewhere. Logically, one must conclude it's the missing icon.

You were missing the small icon.
I did the same mistake and the above step resolved it.
As per the official documentation:
A Notification object must contain the following:
A small icon, set by setSmallIcon()
A title, set by setContentTitle()
Detail text, set by setContentText()
On Android 8.0 (API level 26) and higher, a valid notification channel ID, set by setChannelId() or provided in the NotificationCompat.Builder constructor when creating a channel.
See http://developer.android.com/guide/topics/ui/notifiers/notifications.html

This tripped me up today, but I realized it was because on Android 9.0 (Pie), Do Not Disturb by default also hides all notifications, rather than just silencing them like in Android 8.1 (Oreo) and before. This doesn't apply to notifications.
I like having DND on for my development device, so going into the DND settings and changing the setting to simply silence the notifications (but not hide them) fixed it for me.

Creation of notification channels are compulsory for Android versions after Android 8.1 (Oreo) for making notifications visible. If notifications are not visible in your app for Oreo+ Androids, you need to call the following function when your app starts -
private void createNotificationChannel() {
// Create the NotificationChannel, but only on API 26+ because
// the NotificationChannel class is new and not in the support library
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
CharSequence name = getString(R.string.channel_name);
String description = getString(R.string.channel_description);
int importance = NotificationManager.IMPORTANCE_DEFAULT;
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name,
importance);
channel.setDescription(description);
// Register the channel with the system; you can't change the importance
// or other notification behaviours after this
NotificationManager notificationManager =
getSystemService(NotificationManager.class);
notificationManager.createNotificationChannel(channel);
}
}

You also need to change the build.gradle file, and add the used Android SDK version into it:
implementation 'com.android.support:appcompat-v7:28.0.0'
This worked like a charm in my case.

I think that you forget the
addAction(int icon, CharSequence title, PendingIntent intent)
Look here: Add Action

I had the same issue with my Android app. I was trying out notifications and found that notifications were showing on my Android emulator which ran a Android 7.0 (Nougat) system, whereas it wasn't running on my phone which had Android 8.1 (Oreo).
After reading the documentation, I found that Android had a feature called notification channel, without which notifications won't show up on Oreo devices. Below is the link to official Android documentation on notification channels.
Notifications Overview, Notification anatomy
Create and Manage Notification Channels

For me it was an issue with deviceToken. Please check if the receiver and sender device token is properly updated in your database or wherever you are accessing it to send notifications.
For instance, use the following to update the device token on app launch. Therefore it will be always updated properly.
// Device token for push notifications
FirebaseInstanceId.getInstance().getInstanceId().addOnSuccessListener(
new OnSuccessListener<InstanceIdResult>() {
#Override
public void onSuccess(InstanceIdResult instanceIdResult) {
deviceToken = instanceIdResult.getToken();
// Insert device token into Firebase database
fbDbRefRoot.child("user_detail_profile").child(currentUserId).child("device_token")).setValue(deviceToken)
.addOnSuccessListener(
new OnSuccessListener<Void>() {
#Override
public void onSuccess(Void aVoid) {
}
});
}
});

I encountered a similar problem to yours and while searching for a solution I found these answers but they weren't as direct as I hoped they would be but it gives an Idea; Your notifications may not be showing because for versions >=8 notifications are done relatively differently there is a NotificationChannel which aids in managing notifications this helped me. Happy coding.
void Note(){
//Creating a notification channel
NotificationChannel channel=new NotificationChannel("channel1",
"hello",
NotificationManager.IMPORTANCE_HIGH);
NotificationManager manager=(NotificationManager) getSystemService(NOTIFICATION_SERVICE);
manager.createNotificationChannel(channel);
//Creating the notification object
NotificationCompat.Builder notification=new NotificationCompat.Builder(this,"channel1");
//notification.setAutoCancel(true);
notification.setContentTitle("Hi this is a notification");
notification.setContentText("Hello you");
notification.setSmallIcon(R.drawable.ic_launcher_foreground);
//make the notification manager to issue a notification on the notification's channel
manager.notify(121,notification.build());
}

Make sure your notificationId is unique. I couldn't figure out why my test pushes weren't showing up, but it's because the notification ids were generated based on the push content, and since I was pushing the same notification over and over again, the notification id remained the same.

Notifications may not be shown if you show the notifications rapidly one after the other or cancel an existing one, then right away show it again (e.g. to trigger a heads-up-notification to notify the user about a change in an ongoing notification). In these cases the system may decide to just block the notification when it feels they might become too overwhelming/spammy for the user.
Please note, that at least on stock Android (tested with 10) from the outside this behavior looks a bit random: it just sometimes happens and sometimes it doesn't. My guess is, there is a very short time threshold during which you are not allowed to send too many notifications. Calling NotificationManager.cancel() and then NotificationManager.notify() might then sometimes cause this behavior.
If you have the option, when updating a notification don't cancel it before, but just call NotificationManager.notify() with the updated notification. This doesn't seem to trigger the aforementioned blocking by the system.

If you are on version >= Android 8.1 (Oreo) while using a Notification channel, set its importance to high:
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);

val pendingIntent = PendingIntent.getActivity(applicationContext, 0, Intent(), 0)
var notification = NotificationCompat.Builder(applicationContext, CHANNEL_ID)
.setContentTitle("Title")
.setContentText("Text")
.setSmallIcon(R.drawable.icon)
.setPriority(NotificationCompat.PRIORITY_HIGH)
.setContentIntent(pendingIntent)
.build()
val mNotificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
mNotificationManager.notify(sameId, notification)

How to properly update a notification post api 11?

Before Notification.Builder came into existence the way to update a notification that was already in the notification tray was to call setLatestEventInfo() and then send the notification back through the NotificationManager.notify() call with an ID that matches the first notify() call you made.
Now setLatestEventInfo() is deprecated with the message: Use Notification.Builder instead. But I cannot find any documentation about how to properly update a notification using Notification.Builder.
Are you just suppose to recreate a new Notification instance every time you need to update the notification? Then simply pass that to NotificationManager.notify() with the ID you used before?
It seems to work but I wanted to see if anyone had any official verification that this is the new "way to do this"?
There real reason I am asking this is because in Android 4.1.1 Jelly Bean, the notification now flashes everytime notify() is called. When updating a progress bar with setProgress() this looks really bad and makes it hard to tap on the notification. This was not the case in 4.1 or previous versions. So I want to make sure I am doing this correctly before I file a bug.

I resolved this issue by calling setWhen(0) on my Notification.Builder. It seems Android's default value for this argument doesn't suit updating bits of the notification view without the entire notification fading out / in.
Notification.Builder builder = new Notification.Builder(c)
.setContentTitle("Notification Title")
.setSmallIcon(R.drawable.ic_notification_icon)
.setProgress(max_progress,current_progress,false)
.setWhen(0);
notification = builder.getNotification();
mNotificationManager.notify(NOTIFICATION_ID, notification);
Update:
As WolframRittmeyer stated, using when=0 is not an elegant way. I formed a solution like following:
if(mNotif == null) {
//either setting mNotif first time
//or was lost when app went to background/low memory
mNotif = createNewNotification();
}
else {
long oldWhen = mNotif.when;
mNotif = createNewNotification();
mNotif.when = oldWhen;
}
mNotificationManager.notify(NOTIFICATION_ID, mNotif);

What you are doing is correct, you're just missing the flags you can set. I don't know your particular notification implementation but you might consider using:
setOngoing(boolean ongoing)
or
setOnlyAlertOnce(boolean onlyAlertOnce)

I'm guessing (since I had the same trouble just now) that you are using a RemoteView in your notification. I managed to update the notification without it flashing like this:
RemoteViews views;
if( this.mNotification == null) {
views = new RemoteViews(getPackageName(), R.layout.notification);
this.mNotification = new Notification.Builder(this)
.setContent(views)
.setSmallIcon(R.drawable.status_icon)
.setContentIntent(mNotificationAction)
.setOngoing(true)
.setOnlyAlertOnce(true)
.getNotification();
} else {
views = this.mNotification.contentView;
}
Thanks to #seanmonstar for answering Refresh progress bar in notification bar.

The solution described here works well: Updating an ongoing notification quietly
The key is to use to reuse the builder and setOnlyAlertOnce(true):
if (firstTime) {
mBuilder.setSmallIcon(R.drawable.icon)
.setContentTitle("My Notification")
.setOnlyAlertOnce(true);
firstTime = false;
}
mBuilder.setContentText(message)
.setProgress(100, progress, true);
mNotificationManager.notify(mNotificationId, mBuilder.build());