Develop Reference

NotificationCompatBuilder instance for each Notification Channel?

I'm trying to create two different notifications with two different importance/priority levels. Do I have to create two different instances of a NotificationCompatBuilder:
NotificationCompat.Builder(context, "CHANNEL ID")
NotificationCompat.Builder(context, "CHANNEL ID 2")
since the builder accepts a specific Channel ID as we can see in the example above?

Since Android 8.0 (API 26) all notifications must be assigned to a NotificationChannel. The NotificationChannel controls the priority of the notifications assigned to it with the importance parameter of the NotificationChannel.
Now, when creating the Notification via the Builder You will have the option to use the setPriority method. When it comes to Android 8.0 and later, calls to setPriority will have no effect on the Notification's importance. If You are targetting API < 26, then You will have to use setPriority no matter what the importance of the NotificationChannel of that Notification is.
Now, the answer to Your question is - it depends.
If You are targetting only API >= 26, then You want to use NotificationCompat.Builders with different channel IDs as only NotifcationChannels control the priority.
If You are targetting only API < 26, You will just want to use the setPriority method on the Builder and only one Builder would be enough in that case (but using two, with different channelIds would also be fine).
If You are targetting APIs that are both >= 26 and < 26 then You should use the approach as if You were targetting API >= 26 while additionally calling setPriority on the Builder (You can wrap the call to setPriority in the version check). This approach would require You to have two Builders with different channelIds.

Enable all notification settings by default in my android app

Is there any way I can enable all notification settings by default when my app gets installed ?
Users are receiving notifications but sound is disabled by default and we need to manually enable it on the device. Not all users can do this manually. It would be great to know if there is any way we can check all these things when our app gets installed like WhatsApp or Telegram (they have everything checked by default)

Try using with this below permission in AndroidManifest file
<uses-permission android:name="android.permission.ACCESS_NOTIFICATION_POLICY"/>
and set notification priority for both below and above Oreo versions IMPORTANCE_HIGH for Oreo and above, and PRIORITY_HIGH or PRIORITY_MAX for below Oreo versions
Reference link for priority note
Priority for version below Oreo
mBuilder.setSmallIcon(R.drawable.app_logo)
.setAutoCancel(true)
.setContentIntent(resultPendingIntent)
.setContentTitle(title)
.setStyle(bigPictureStyle)
.setSound(soundUri)
.setPriority(NotificationCompat.PRIORITY_HIGH) // prirority here for version below Oreo
.setWhen(System.currentTimeMillis())
.setLargeIcon(BitmapFactory.decodeResource(mCtx.getResources(), R.drawable.app_logo))
.setContentText(message)
.build();
Priority for Oreo and above
Refer this link

WhatsApp, Telegram, Snapchat, and so on. These are all white-listed apps which means the package names are hardcoded at OS level to allow some of the permissions enabled by default. Our apps are not so. Hence, we need the user to enable those permissions manually.
You can check this by yourself. Create a new android application give the package name of the Telegram application(org.telegram.messenger) and just run it. Don't do any code at all, and no need to open the app too. Simply go to the notification settings of the newly created application, where you find all the permissions enabled by default.
Hope you got the answer.

Android 8 or higher you need to use NotificationChannel to enable sound, vibration, sound etc.
Uri notification_sound = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationChannel notificationChannel = new NotificationChannel(CHANNEL_ID, CHANNEL_NAME, NotificationManager.IMPORTANCE_HIGH);
AudioAttributes attributes = new AudioAttributes.Builder()
.setUsage(AudioAttributes.USAGE_NOTIFICATION)
.build();
notificationChannel.setSound(notification_sound, attributes);//for enable sound
notificationChannel.enableLights(true);
notificationManager.createNotificationChannel(notificationChannel);
}
but in Redmi note 5 pro (MIUI 10.2.1.0) still notification sound is disabled. I think there is a bug in MIUI. Run this same code in mi A1(Android one mobile) everything fine. It works.
refer this link to know more about Notification Channel

Firebase cloud messaging stopped with upgrade to Oreo

I was just getting started with Android development and managed to get Firebase messaging working after running the wizard. I was able to receive background notifications on my Nexus 5X running Nougat. But then my 5X upgraded to Oreo and Firebase notifications haven't worked since. I've heard about background execution limitations, but since I'm just getting started I don't know what I actually have to do to get it working again. Are there any write ups on this? I tried a new project from scratch hoping the wizard had been updated, but no change. I was using application broadcast messages and topic subscription messages, no device token used.

When you target Android 8.0 (API level 26), you must implement one or more notification channels to display notifications to your users. If you don't target Android 8.0 (API level 26) but your app is used on devices running Android 8.0 (API level 26), your app behaves the same as it would on devices running Android 7.1 (API level 25) or lower.
If you change your target version into Android 8.0 (API level 26), you have to do the following change
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
String id = "id_product";//This will be enter when creating Builder
// The user-visible name of the channel.
CharSequence name = "Product";
// The user-visible description of the channel.
String description = "Notifications regarding our products";
int importance = NotificationManager.IMPORTANCE_MAX;
NotificationChannel mChannel = new NotificationChannel(id, name, importance);
// Configure the notification channel.
mChannel.setDescription(description);
mChannel.enableLights(true);
// Sets the notification light color for notifications posted to this
// channel, if the device supports this feature.
mChannel.setLightColor(Color.RED);
notificationManager.createNotificationChannel(mChannel);
}
Change your Builder constructor
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(applicationContext, **ID you have put in the Notification Channel**)
Finally you can create the notification from the Builder
notificationManager.notify("0", notificationBuilder.build())
Ref: https://developer.android.com/guide/topics/ui/notifiers/notifications.html#ManageChannels

Please use a recent version of the FCM sdk.
FCM sdk introduced support for Android O in April, if you are using older version your app would not receive messages in Android O and could potentially crash.
See the latest release here: https://firebase.google.com/support/release-notes/android
PS: firebase SDK has been moved to the Google Maven repository.
Be sure to check out the latest instructions here:
https://firebase.google.com/docs/android/setup#manually_add_firebase

Heads-up Notification - Android Lollipop

I'm trying to show a notification-type heads-up but I could not. What I tried
final Notification.Builder notif = new Builder(getApplicationContext())
.setContentTitle(getString(R.string.title))
.setContentText(getString(R.string.text))
// .setTicker(getString(R.string.tick)) removed, seems to not show at all
// .setWhen(System.currentTimeMillis()) removed, match default
// .setContentIntent(contentIntent) removed, I don't neet it
.setColor(Color.parseColor(getString(R.color.yellow))) //ok
.setSmallIcon(R.drawable.ic_small) //ok
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher))
// .setCategory(Notification.CATEGORY_CALL) does not seem to make a difference
.setPriority(Notification.PRIORITY_MAX); //does not seem to make a difference
// .setVisibility(Notification.VISIBILITY_PRIVATE); //does not seem to make a difference
mNotificationManager.notify(Constants.NOTIFICATION_ID, notif.build());
The notification is shown only as an icon in the bar.
I'm using API 21 on API 21 emulator (not L preview)
I have tried:
android:Theme.Holo.NoActionBar,
android:Theme.Holo.NoActionBar.Fullscreen
and NotificationCompat.Builder
SDK examples are not available. does anyone know how to do it?
I made it working by adding:
.setDefaults(Notification.DEFAULT_VIBRATE)
is this the best way?

According to Notifications, you are required to set a vibrate or ringtone to make Heads-up work. However, here's a quick hack that doesn't require VIBRATE permission to produce a head-up notification:
notificationBuilder.setPriority(Notification.PRIORITY_HIGH);
if (Build.VERSION.SDK_INT >= 21) notificationBuilder.setVibrate(new long[0]);
EDIT:
Don't abuse heads-up notification. See here for when to use heads-up notification:
MAX: 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.
HIGH: Primarily for important communication, such as messages or chat events with content that is particularly interesting for the user. High-priority notifications trigger the heads-up notification display.

According to Google:
https://developer.android.com/design/patterns/notifications.html
If a notification's priority is flagged as High, Max, or full-screen, it gets a heads-up notification.
So the following code should generate an heads-up notification:
.setPriority(Notification.PRIORITY_MAX)
Should be enough. But apparently the .setDefaults(Notification.DEFAULT_VIBRATE) has to be set also. Hopefully Google will fix this in their final release of Android 5.0.
Not sure if bug or feature...

All my apps doesn´t show the Notification, for example i have a Nexus 6 with Android 5.1.1, but i think this is an issuse since Android 5.0, i had to set:
.setPriority(Notification.PRIORITY_HIGH)
Correctly set and manage notification priority
Android supports a priority flag for notifications. This flag allows you to influence where your notification appears, relative to other notifications, and helps ensure that users always see their most important notifications first. You can choose from the following priority levels when posting a notification:
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.
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.
DEFAULT Use for all notifications that don't fall into any of the other priorities described here and if the application does not
prioritize its own notifications
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.
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.

To set the priority, use the setPriority function (introduced in API 16) alongwith setDefaults (added in API 11) of Notification Builder. Choose the priority DEFAULT, HIGH, LOW, MAX, MIN as per the requirement of your app. Defaults can also be chosen here.
A small snippet:
notification = NotificationBuilder(service)
notification.setPriority(Notification.PRIORITY_MAX)
notification.setDefaults(Notification.DEFAULT_ALL)

Please check that your phone is not in “silent” or “do not disturb” mode. I spent day before I found it. I just leave this comment for those who get the same problem and found this question.

Should set high priority and use ringtones or vibrations.
notificationBuilder.setDefaults(Notification.DEFAULT_ALL);
notificationBuilder.setPriority(Notification.PRIORITY_HIGH);
Ref: https://developer.android.com/guide/topics/ui/notifiers/notifications.html#Heads-up
Heads-up Notifications
With Android 5.0 (API level 21), notifications can appear in a small
floating window (also called a heads-up notification) when the device
is active (that is, the device is unlocked and its screen is on).
These notifications appear similar to the compact form of your
notification, except that the heads-up notification also shows action
buttons. Users can act on, or dismiss, a heads-up notification without
leaving the current app.
Examples of conditions that may trigger heads-up notifications
include:
The user's activity is in fullscreen mode (the app uses fullScreenIntent), or
The notification has high priority and uses ringtones or vibrations

For devices running Android 8.0 (API level 26) and higher the notification channel requires high importance
new NotificationChannel("ID", "Channel Name", NotificationManager.IMPORTANCE_HIGH);

Add this line in your code to display heads up notification it's only working for Lollipop version
notificationBuilder.setPriority(Notification.PRIORITY_HIGH);

You don't need to set vibrate. You only need to set sound. It's less intrusive. I don't get any sound on mine, but the notification displays on top. Make sure you use PRIORITY_HIGH and DEFAULT_SOUND.
NotificationChannel channel = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
channel = new NotificationChannel("my_channel_01",
"Channel human readable title",
NotificationManager.IMPORTANCE_HIGH);
mNotificationManager.createNotificationChannel(channel);
}
Notification notification =
new NotificationCompat.Builder(this, "notify_001")
.setSmallIcon(R.drawable.ic_check)
.setContentTitle("My notification")
.setContentText("Hello World!")
.setPriority(Notification.PRIORITY_HIGH)
.setDefaults(NotificationCompat.DEFAULT_SOUND)
.setChannelId("my_channel_01").build();
mNotificationManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.notify(0, notification);

Vibrate an Android Wear device on notification

I'm trying to develop an app for android and Android Wear (Wear OS). I create a Notification from the mobile to the watch.
notification = new NotificationCompat.Builder(context)
.setSmallIcon(icon)
.setVibrate(new long[]{1000, 1000, 1000, 1000, 1000, 1000})
.setContentTitle(title)
.setContentText(content)
.setStyle(bigStyle.bigText(content))
.setLargeIcon(BitmapFactory.decodeResource(context.getResources(), background))
.build();
In the manifest of the watch I set:
<uses-permission android:name="android.permission.VIBRATE"/>
Unfortunately, there is no vibration. How can I fix it?
Thanks.

.setDefaults(Notification.DEFAULT_ALL)
This line of code will make the wear wake up and vibrate.

I would like to add 1 more updated answer for SDK 26 and above. I spent many hours trying to determine why my notifications would not vibrate on the Android Wear watch.
I eventually noticed that someone had set the priority on the notification channel to IMPORTANCE_MIN.
if (Build.VERSION.SDK_INT >= 26) {
NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
NotificationChannel notificationChannel = new NotificationChannel(Config.NOTIFICATION_CHANNEL_ID, Config.NOTIFICATION_CHANNEL_NAME, NotificationManager.IMPORTANCE_MIN);
notificationManager.createNotificationChannel(notificationChannel);
}
To fix the issue, I did the following:
Uninstalled the app from the phone
Changed the priority to HIGH [Though I suspect NORMAL will work also]
Reinstalled the app
Updated Code:
NotificationChannel(Config.NOTIFICATION_CHANNEL_ID, Config.NOTIFICATION_CHANNEL_NAME, NotificationManager.IMPORTANCE_HIGH);
Note: You also need to ensure that your defaults are correct as 'Android enthusiast' pointed out in his earlier answer.
I hope it saves someone from an investigation.