Send android notification

android_send_notification.java

// https://alvinalexander.com/android/how-to-create-android-notifications-notificationmanager-examples
public void showNotification(String s){
    PendingIntent pi = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
    Notification notification = new NotificationCompat.Builder(this)
        .setTicker("Demo")
        .setSmallIcon(android.R.drawable.ic_menu_help)
        .setContentTitle("Demo Notification")
        .setContentText(s)
        .setContentIntent(pi)
        .setAutoCancel(true)
        .build();

    NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    notificationManager.notify(0, notification);
}