On Android 8.1 API 27 notification does not display

Question

I get Toast on Android 8.1 API 27:

Developer warning for package "my_package_name"
Failed to post notification on ...

Logcat includes next strings:

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

W/Notification: See the documentation of setSound() for what to use instead with android.media.AudioAttributes to qualify your playback use case

E/NotificationService: No Channel found for pkg=my_package_name

The full information in the Toast and in Logcat can help in the localization this problem.

Answer 1

If you get this error should be paid attention to 2 items and them order:

1. NotificationChannel mChannel = new NotificationChannel(id, name, importance);
2. builder = new NotificationCompat.Builder(context, id);

Also NotificationManager notifManager and NotificationChannel mChannel are created only once.

There are required setters for Notification:

• builder.setContentTitle() // required
• .setSmallIcon() // required
• .setContentText() // required

See example:

private NotificationManager notifManager; public void createNotification(String aMessage, Context context) {     final int NOTIFY_ID = 0; // ID of notification     String id = context.getString(R.string.default_notification_channel_id); // default_channel_id     String title = context.getString(R.string.default_notification_channel_title); // Default Channel     Intent intent;     PendingIntent pendingIntent;     NotificationCompat.Builder builder;     if (notifManager == null) {         notifManager = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);     }     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {         int importance = NotificationManager.IMPORTANCE_HIGH;         NotificationChannel mChannel = notifManager.getNotificationChannel(id);         if (mChannel == null) {             mChannel = new NotificationChannel(id, title, importance);             mChannel.enableVibration(true);             mChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});             notifManager.createNotificationChannel(mChannel);         }         builder = new NotificationCompat.Builder(context, id);         intent = new Intent(context, MainActivity.class);         intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);         pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);         builder.setContentTitle(aMessage)                            // required                .setSmallIcon(android.R.drawable.ic_popup_reminder)   // required                .setContentText(context.getString(R.string.app_name)) // required                .setDefaults(Notification.DEFAULT_ALL)                .setAutoCancel(true)                .setContentIntent(pendingIntent)                .setTicker(aMessage)                .setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});     }     else {         builder = new NotificationCompat.Builder(context, id);         intent = new Intent(context, MainActivity.class);         intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);         pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);         builder.setContentTitle(aMessage)                            // required                .setSmallIcon(android.R.drawable.ic_popup_reminder)   // required                .setContentText(context.getString(R.string.app_name)) // required                .setDefaults(Notification.DEFAULT_ALL)                .setAutoCancel(true)                .setContentIntent(pendingIntent)                .setTicker(aMessage)                .setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400})                .setPriority(Notification.PRIORITY_HIGH);     }     Notification notification = builder.build();     notifManager.notify(NOTIFY_ID, notification); }