Notifications fail to display in Android Oreo (API 26)

Question

I get this message when trying to display a notification on Android O.

Use of stream types is deprecated for operations other than volume control

Answer 1

All that @sky-kelsey has described is good, Just minor additions:

You should not register same channel every time if it has been already registered, so I have Utils class method that creates a channel for me:

public static final String NOTIFICATION_CHANNEL_ID_LOCATION = "notification_channel_location";

public static void registerLocationNotifChnnl(Context context) {
    if (Build.VERSION.SDK_INT >= 26) {
        NotificationManager mngr = (NotificationManager) context.getSystemService(NOTIFICATION_SERVICE);
        if (mngr.getNotificationChannel(NOTIFICATION_CHANNEL_ID_LOCATION) != null) {
            return;
        }
        //
        NotificationChannel channel = new NotificationChannel(
                NOTIFICATION_CHANNEL_ID_LOCATION,
                context.getString(R.string.notification_chnnl_location),
                NotificationManager.IMPORTANCE_LOW);
        // Configure the notification channel.
        channel.setDescription(context.getString(R.string.notification_chnnl_location_descr));
        channel.enableLights(false);
        channel.enableVibration(false);
        mngr.createNotificationChannel(channel);
    }
}

strings.xml:

Location polling
You will see notifications on this channel ONLY during location polling

And I call the method every time before I'm going to show a notification of the type:

    ...
    NotificationUtil.registerLocationNotifChnnl(this);
    return new NotificationCompat.Builder(this, NotificationUtil.NOTIFICATION_CHANNEL_ID_LOCATION)
            .addAction(R.mipmap.ic_launcher, getString(R.string.open_app),
                    activityPendingIntent)
            .addAction(android.R.drawable.ic_menu_close_clear_cancel, getString(R.string.remove_location_updates),
                    servicePendingIntent)
            .setContentText(text)
            ...

---

Another typical problem - channel default sound - described here: https://stackoverflow.com/a/45920861/2133585