Status Bar Notification Not Showing?

Question

I have a simple method which onclick() of a Button should generate status bar notification, but for some reason, it isn't showing up.

public void createNotification() {
    NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
            .setSmallIcon(android.R.drawable.ic_dialog_alert)
            .setContentTitle("Notification!")
            .setContentText("This is my first notification!");
    Notification notification = builder.build();
    NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
    notificationManager.notify(0, notification);
}

Answer 1

In Android 8 (API level 26), all notifications must be assigned to a channel. This work for me:

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(getContext(), CHANNEL_ID)
            .setSmallIcon(R.drawable.emo_no_paint_120)
            .setContentTitle("title")
            .setContentText("content")
            .setColor(Color.parseColor("#009add"))
            .setAutoCancel(true);

    NotificationManager notificationManager = (NotificationManager) getContext().getSystemService(
            NOTIFICATION_SERVICE);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, CHANNEL_NAME, NotificationManager.IMPORTANCE_HIGH);

        notificationManager.createNotificationChannel(mChannel);
    }

    notificationManager.notify(0, mBuilder.build());

And you should add AppCompat library

implementation 'com.android.support:support-compat:27.1.0'

You could check official Android Docs

Answer 2

Your code is okay. But since you are targeting Android 8.0, you need to implement Notification Channels since this the preferred way in Android Oreo.

https://developer.android.com/guide/topics/ui/notifiers/notifications.html