Send SMS in android

package com.example.code;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.app.Activity;

import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.telephony.SmsManager;

import android.util.Log;
import android.view.Menu;
import android.view.View;

import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
   private static final int MY_PERMISSIONS_REQUEST_SEND_SMS =0 ;
   Button sendBtn;
   EditText txtphoneNo;
   EditText txtMessage;
   String phoneNo;
   String message;

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

      sendBtn = (Button) findViewById(R.id.btnSendSMS);
      txtphoneNo = (EditText) findViewById(R.id.editText);
      txtMessage = (EditText) findViewById(R.id.editText2);

      sendBtn.setOnClickListener(new View.OnClickListener() {
         public void onClick(View view) {
            sendSMSMessage();
         }
      });
   }
	
   protected void sendSMSMessage() {
      phoneNo = txtphoneNo.getText().toString();
      message = txtMessage.getText().toString();
		
      if (ContextCompat.checkSelfPermission(this,
         Manifest.permission.SEND_SMS)
         != PackageManager.PERMISSION_GRANTED) {
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
               Manifest.permission.SEND_SMS)) {
            } else {
               ActivityCompat.requestPermissions(this,
                  new String[]{Manifest.permission.SEND_SMS},
                  MY_PERMISSIONS_REQUEST_SEND_SMS);
            }
      }
   }
	
   @Override
   public void onRequestPermissionsResult(int requestCode,String permissions[], int[] grantResults) {
      switch (requestCode) {
         case MY_PERMISSIONS_REQUEST_SEND_SMS: {
            if (grantResults.length > 0
               && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                  SmsManager smsManager = SmsManager.getDefault();
                  smsManager.sendTextMessage(phoneNo, null, message, null, null);
                  Toast.makeText(getApplicationContext(), "SMS sent.", 
                     Toast.LENGTH_LONG).show();
            } else {
               Toast.makeText(getApplicationContext(), 
                  "SMS faild, please try again.", Toast.LENGTH_LONG).show();
               return;
            }
         }
      }

   }
}