Failed to post notification on channel “null” Target Api is 26

Question

Two log showing

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

2: See the documentation of setSound() for what to use instea

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(this, 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 the example in On Android 8.1 API 27 notification does not display.