Sending messages with android studio

Best regards to all the problem is this:

I have this code to send text messages works perfectly but I would like to know how I can do that when a message is not sent by any problem that is presented to the application in automatic, retry sending it again about 3 times.

public class MainActivity extends Activity {

EditText txtPhone;
EditText txtMsg;
Button btnSend; 

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

  txtPhone = ((EditText)findViewById(R.id.txtPhone ));
  txtMsg = ((EditText)findViewById(R.id.txtMsg ));
  btnSend = ((Button)findViewById(R.id.btnSend ));

  btnSend.setOnClickListener(
            new View.OnClickListener() {
                public void onClick(View view) {               

                 PendingIntent sentIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, new Intent("SMS_SENT"), 0);

                 registerReceiver(new BroadcastReceiver() {

            @Override
            public void onReceive(Context context, Intent intent) {
             switch (getResultCode()){
              case Activity.RESULT_OK:     
               Toast.makeText(getApplicationContext(), "SMS enviado", Toast.LENGTH_SHORT).show();
                                 break;
              case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
               Toast.makeText(getApplicationContext(), "No se pudo enviar SMS", Toast.LENGTH_SHORT).show();
               break;
              case SmsManager.RESULT_ERROR_NO_SERVICE:
               Toast.makeText(getApplicationContext(), "Servicio no diponible", Toast.LENGTH_SHORT).show();
               break;
              case SmsManager.RESULT_ERROR_NULL_PDU:
               Toast.makeText(getApplicationContext(), "PDU (Protocol Data Unit) es NULL", Toast.LENGTH_SHORT).show();
               break;
              case SmsManager.RESULT_ERROR_RADIO_OFF: 
               Toast.makeText(getApplicationContext(), "Failed because radio was explicitly turned off", Toast.LENGTH_SHORT).show();
               break;
             }
            }       
              }, new IntentFilter("SMS_SENT"));

                 SmsManager sms = SmsManager.getDefault(); 
                 if( txtPhone.getText().toString().length()> 0 &&
                     txtMsg.getText().toString().length()>0 )
                 {                      
                  sms.sendTextMessage( txtPhone.getText().toString() , null, txtMsg.getText().toString() , sentIntent, null); 
                 }
                 else
                 {
                  Toast.makeText(getApplicationContext(), "No se puede enviar, los datos son incorrectos", Toast.LENGTH_SHORT).show();
                 }
                }});
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
 getMenuInflater().inflate(R.menu.main, menu);
return true;
  }

 }