Android - why ContentObserver invokes itself?

Question

Hi,

I am trying to delete received SMS in ContentObserver (on "content://sms/") onChange() method using contentResolver.delete, but after deleting ContentObserver is invoked one more time.

Could you explaing my, whe ContentObserver invokes itself despite deliverSelfNotifications() returns false?

I foud soultion to uregister ContentObserver before deleting the sms and register again after, but is inelegant.

My code:

  private class SmsMmsContentObserver extends ContentObserver {
    public SmsMmsContentObserver(Handler handler)
    {
      super(handler);
    }


    @Override public boolean deliverSelfNotifications() { 
        return false; 
        }


    @Override
    public void onChange(boolean selfChange) {
      super.onChange(selfChange);


      Uri uriSMSURI = Uri.parse("content://sms/");
      Cursor cur = getContentResolver().query(uriSMSURI, null, null,
                   null, null);
      if (cur.moveToNext())
      {     
        int threadIdIn = cur.getInt(cur.getColumnIndex("thread_id"));
           getContentResolver().delete(Uri.parse("content://sms/conversations/" + threadIdIn), null, null);
      }


    }
  }

Methods to register observer in on of services.

private void registerSmsMmsObserver()
  {
   if (observer == null)
   {
       observer = new SmsMmsContentObserver(new Handler());
       contentResolver = getContentResolver();
       contentResolver.registerContentObserver(uriSmsMms, true, observer);
   }
  }


  private void unregisterSmsMmsObserver() 
  {
   if (contentResolver != null) 
    contentResolver.unregisterContentObserver(observer);
   observer = null;
  }