[android] 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 " + "[email protected]")
        .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);

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) {

                    }
                });
    }
});

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.

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);
   }
}

I think that you forget the

addAction(int icon, CharSequence title, PendingIntent intent)

Look here: Add Action

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 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

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.

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);

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:

1. A small icon, set by setSmallIcon()

2. A title, set by setContentTitle()

3. Detail text, set by setContentText()

4. 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