Send SMS message and get the result

Code snippet:
public void sendSmsMessage(String phoneNumber,String message){
        SmsManager smsManager = SmsManager.getDefault();
        ArrayList<String> messageList = smsManager.divideMessage(message);
        PendingIntent mPI = PendingIntent.getBroadcast(MainEntryActivity.this, 0, new Intent("SMS_SENT"), PendingIntent.FLAG_UPDATE_CURRENT);
        ArrayList<PendingIntent> sentIntents = new ArrayList<PendingIntent>();
        for(int i=0;i<messageList.size();i++){
            sentIntents.add(mPI);
        }
        registerReceiver(smsSentReceiver, new IntentFilter("SMS_SENT"));
        smsManager.sendMultipartTextMessage (phoneNumber, null, messageList, sentIntents, null);
}

private BroadcastReceiver smsSentReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String result = "";
            switch(getResultCode()) {
                case Activity.RESULT_OK:
                    result = "Transmission successful";
                    break;
                case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
                    result = "Transmission failed";
                    break;
                case SmsManager.RESULT_ERROR_RADIO_OFF:
                    result = "Radio off";
                    break;
                case SmsManager.RESULT_ERROR_NULL_PDU:
                    result = "No PDU defined";
                    break;
                case SmsManager.RESULT_ERROR_NO_SERVICE:
                    result = "No service";
                    break;
            }
            Log.d(TAG, "send sms result: " + result);
        }
};

@Override
protected void onDestroy() {
        try{
            unregisterReceiver(smsSentReceiver);
        } catch(IllegalArgumentException iae){
            Log.d(TAG,"Receiver not registered");
            iae.printStackTrace();
        }
}