SMS によるテキストメッセージの送信 - 送信済み状態の取得

package com.example.sms2;

import android.os.Bundle;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.telephony.SmsManager;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity {

  final String ACTION_SENT = "com.example.sms2.ACTION_SENT";
  PendingIntent sentIntent;
  SMSSentBroadcastReceiver sentBroadcastReceiver;
  Button sendButton;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    sentIntent = PendingIntent.getBroadcast(
      this, 0, new Intent(ACTION_SENT), 0);
    
    sendButton = (Button)findViewById(R.id.sendButton);
    sendButton.setOnClickListener(new OnClickListener(){
      @Override
      public void onClick(View v) {
        SmsManager smsManager = SmsManager.getDefault();
        String destinationAddress = "1234567890";
        String scAddress = null;
        String text = "Hello!";
        
        smsManager.sendTextMessage(
          destinationAddress,
          scAddress,
          text,
          sentIntent,
          null);
      
      }
    });
  }
  
  
  @Override
  protected void onPause() {
    super.onPause();
    unregisterReceiver(sentBroadcastReceiver);
  }
  
  
  @Override
  protected void onResume() {
    super.onResume();
    
    sentBroadcastReceiver = new SMSSentBroadcastReceiver();
    registerReceiver(sentBroadcastReceiver, 
      new IntentFilter(ACTION_SENT));
  }
  
  
  class SMSSentBroadcastReceiver extends BroadcastReceiver {
  
    @Override
    public void onReceive(Context context, Intent intent) {
      switch(getResultCode()){
      case Activity.RESULT_OK:
        Toast.makeText(getBaseContext(), 
          "SMS Sent", Toast.LENGTH_SHORT).show();
        break;
      case Activity.RESULT_CANCELED:
        Toast.makeText(getBaseContext(), 
          "SMS Canceled", 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;
      }
    }
    
  }