Android: Verify phone number using sms to self

I'm trying to add a phone number verification to my app by sending sms to a number the user entered and I want to check if this device received my sms.

So I have a void sendSMS(String phoneNumber, String message) which I found in another thread here:

  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);
}

I assume I need to add the verifying part in the second onReceive, but I don't know how. Can anyone help me fill the missing piss of the puzzle? Thanks.

EDIT#1: Just to make it clear I saw the question that my question might be a duplicate of, I tried adding the:

@Override
public void onReceive(Context context, Intent intent)

{
Bundle extras = intent.getExtras();

if (extras == null)
    return;

Object[] pdus = (Object[]) extras.get("pdus");
SmsMessage msg = SmsMessage.createFromPdu((byte[]) pdus[0]);
String origNumber = msg.getOriginatingAddress();
String msgBody = msg.getMessageBody();
...
... 

}

in the second onReceive method but the Object[] pdus = (Object[]) extras.get("pdus") is a null, and I can't figure out why.

EDIT#2: I tried adding:

registerReceiver(new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(getBaseContext(), "sms received",
                    Toast.LENGTH_SHORT).show();
        }
    }, new IntentFilter("android.provider.Telephony.SMS_RECEIVED"));

but it doesn't seem to work, i.e I don't get the toast "sms received".

EDIT#3(the solution): Because i'm running the app on my oneplus that runs android M I have to ask for the "RECEIVE_SMS" in runtime. But because I gave the app the "SMS" permission manually through settings I was sure that it covered the "RECEIVE_SMS" as well. But it didn't. So I had to ask for it explicitly on runtime. The final code draft is:

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));

    IntentFilter intentFilter = new IntentFilter("android.provider.Telephony.SMS_RECEIVED");
    registerReceiver(new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(getBaseContext(), "SMS RECEIVED",
                    Toast.LENGTH_SHORT).show();

            Bundle extras = intent.getExtras();
            if (extras == null)
                return;

            Object[] pdus = (Object[]) extras.get("pdus");
            SmsMessage msg = SmsMessage.createFromPdu((byte[]) pdus[0]);
            String origNumber = msg.getOriginatingAddress();
            String msgBody = msg.getMessageBody();
            // Now one can just match the msgBody with the expected
            // confirmation code for example.
        }
    }, intentFilter);

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