Do I need to unregister an “anonymous” BroadcastReceiver

I recently asked a question about checking the status of a sent SMS, and the answer was a piece of code that registered two “anonymous internal” ones (please correct my terminology if this is incorrect) BroadcastReceiversin order to listen to the sent SMS / delivered broadcasts. These receivers were only needed to receive data that my application was just sent, so I did not need to listen constantly.

My immediate thought was “OK, I will need to unregister after I’ve finished with them,” but is that right? I asked for a poster because it did not include any unregistered code, but did not receive a response. The code seems like a pretty standard way of doing what I want, as it appears on numerous Android dev sites. There he is:

//---sends an SMS message to another device---
private void sendSMS(String phoneNumber, String message)
{        
    String SENT = "SMS_SENT";
    String DELIVERED = "SMS_DELIVERED";

    PendingIntent sentPI = PendingIntent.getBroadcast(this, 0,
        new Intent(SENT), 0);

    PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0,
        new Intent(DELIVERED), 0);

    //---when the SMS has been sent---
    registerReceiver(new BroadcastReceiver(){
        @Override
        public void onReceive(Context arg0, Intent arg1) {
            switch (getResultCode())
            {
                case Activity.RESULT_OK:
                    Toast.makeText(getBaseContext(), "SMS sent", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
                    Toast.makeText(getBaseContext(), "Generic failure", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_NO_SERVICE:
                    Toast.makeText(getBaseContext(), "No service", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_NULL_PDU:
                    Toast.makeText(getBaseContext(), "Null PDU", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case SmsManager.RESULT_ERROR_RADIO_OFF:
                    Toast.makeText(getBaseContext(), "Radio off", 
                            Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    }, new IntentFilter(SENT));

    //---when the SMS has been delivered---
    registerReceiver(new BroadcastReceiver(){
        @Override
        public void onReceive(Context arg0, Intent arg1) {
            switch (getResultCode())
            {
                case Activity.RESULT_OK:
                    Toast.makeText(getBaseContext(), "SMS delivered", 
                            Toast.LENGTH_SHORT).show();
                    break;
                case Activity.RESULT_CANCELED:
                    Toast.makeText(getBaseContext(), "SMS not delivered", 
                            Toast.LENGTH_SHORT).show();
                    break;                        
            }
        }
    }, new IntentFilter(DELIVERED));        

    SmsManager sms = SmsManager.getDefault();
    sms.sendTextMessage(phoneNumber, null, message, sentPI, deliveredPI);

The code is working fine.

What's more, he does not receive notifications about any sent or sent SMS messages that occur outside of my application. For instance. I can send SMS after these BroadcastReceivershave been registered and do not see messages Toast.

So, I have two questions:

• Do I need to unregister these BroadcastReceivers?
• If not, why not?