Android O reporting notification not posted to channel - but it is

Question

Couple Android O notification questions:

1) I have created a Notification Channel (see below), am calling the builder with .setChannelId() (passing in the name of th

Answer 1

You gotta create a channel before.

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 behaviors after this
            NotificationManager notificationManager = getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }
}

public void notifyThis(String title, String message) {
        NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, CHANNEL_ID)
                .setSmallIcon(R.drawable.green_circle)
                .setContentTitle(title)
                .setContentText(message)
                .setPriority(NotificationCompat.PRIORITY_DEFAULT);

        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);

        // notificationId is a unique int for each notification that you must define
        notificationManager.notify(0, mBuilder.build());
}

Finally you call this method:

createNotificationChannel();
notifyThis("My notification", "Hello World!");