How to receive SMS messages from a specific number?

I want to receive messages from a specific number. When I run the app, I get messages from everyone in my inbox. I got the source code from this site (android authority)

 package com.nqr.smsapp;

 import android.Manifest; import android.content.ContentResolver;
 import android.content.pm.PackageManager; import
 android.database.Cursor; import android.net.Uri; import
 android.support.annotation.NonNull; import
 android.support.v4.content.ContextCompat; import
 android.support.v7.app.AppCompatActivity; import android.os.Bundle;
 import android.telephony.SmsManager; import android.view.View; import
 android.widget.ArrayAdapter; import android.widget.EditText; import
 android.widget.ListView; import android.widget.Toast;

 import java.util.ArrayList;

 public class MainActivity extends AppCompatActivity {

     ArrayList<String> smsMessagesList = new ArrayList<>();
     ListView messages;
     ArrayAdapter arrayAdapter;
     EditText input;
     SmsManager smsManager = SmsManager.getDefault();
     private static MainActivity inst;

     private static final int READ_SMS_PERMISSIONS_REQUEST = 1;

     public static MainActivity instance() {
         return inst;
     }

     @Override
     public void onStart() {
         super.onStart();
         inst = this;
     }


     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         messages = (ListView) findViewById(R.id.messages);
         input = (EditText) findViewById(R.id.input);
         arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, smsMessagesList);
         messages.setAdapter(arrayAdapter);
         if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_SMS)
                 != PackageManager.PERMISSION_GRANTED) {
             getPermissionToReadSMS();
         } else {
             refreshSmsInbox();
         }


     }

     public void updateInbox(final String smsMessage) {
         arrayAdapter.insert(smsMessage, 0);
         arrayAdapter.notifyDataSetChanged();
     }

    public void onSendClick(View view) {

     if (ContextCompat.checkSelfPermission(this, Manifest.permission.SEND_SMS)
             != PackageManager.PERMISSION_GRANTED) {
         getPermissionToReadSMS();
     } else {
         smsManager.sendTextMessage("07911127456", null, input.getText().toString(), null, null);
         Toast.makeText(this, "Message sent!", Toast.LENGTH_SHORT).show();
     } }

         public void getPermissionToReadSMS() {
             if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_SMS)
                     != PackageManager.PERMISSION_GRANTED) {
                 if (shouldShowRequestPermissionRationale(
                         Manifest.permission.READ_SMS)) {
                     Toast.makeText(this, "Please allow permission!", Toast.LENGTH_SHORT).show();
                 }
                 requestPermissions(new String[]{Manifest.permission.READ_SMS},
                         READ_SMS_PERMISSIONS_REQUEST);
             }
         }


     @Override
     public void onRequestPermissionsResult(int requestCode,
                                            @NonNull String permissions[],
                                            @NonNull int[] grantResults) {
         // Make sure it's our original READ_CONTACTS request
         if (requestCode == READ_SMS_PERMISSIONS_REQUEST) {
             if (grantResults.length == 1 &&
                     grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                 Toast.makeText(this, "Read SMS permission granted", Toast.LENGTH_SHORT).show();
                 refreshSmsInbox();
             } else {
                      Toast.makeText(this, "Read SMS permission denied", Toast.LENGTH_SHORT).show();
                     }

             } else {
                 super.onRequestPermissionsResult(requestCode, permissions, grantResults);
             }



         }

             public void refreshSmsInbox() {
             ContentResolver contentResolver = getContentResolver();
             Cursor smsInboxCursor = contentResolver.query(Uri.parse("content://sms/inbox"), null, null,
 null, null);
             int indexBody = smsInboxCursor.getColumnIndex("body");
             int indexAddress = smsInboxCursor.getColumnIndex("address");
             if (indexBody < 0 || !smsInboxCursor.moveToFirst()) return;
             arrayAdapter.clear();
             do {
                 String str = "SMS From: " + smsInboxCursor.getString(indexAddress) +
                         "\n" + smsInboxCursor.getString(indexBody) + "\n";
                 arrayAdapter.add(str);
             } while (smsInboxCursor.moveToNext()); //messages.setSelection(arrayAdapter.getCount() - 1);
     }



 }
> 

I want the messages to be delivered from a specific number to my inbox: for instance messages only from 07911 127456 in my inbox

I only need a specific conversation

broadcast receiver

package com.nqr.smsapp;


        import android.content.BroadcastReceiver;
        import android.content.Context;
        import android.content.Intent;
        import android.os.Bundle;
        import android.telephony.SmsMessage;

public class SmsBroadcastReceiver extends BroadcastReceiver {

    public static final String SMS_BUNDLE = "pdus";

    public void onReceive(Context context, Intent intent) {
        Bundle intentExtras = intent.getExtras();

            if (intentExtras != null) {
            Object[] sms = (Object[]) intentExtras.get(SMS_BUNDLE);
            String smsMessageStr = "";
            for (int i = 0; i < sms.length; ++i) {
                String format = intentExtras.getString("format");
                SmsMessage smsMessage = SmsMessage.createFromPdu((byte[]) sms[i], format);

                String smsBody = smsMessage.getMessageBody().toString();
                String address = smsMessage.getOriginatingAddress();

                smsMessageStr += "SMS From: " + address + "\n";
                smsMessageStr += smsBody + "\n";
            }

            MainActivity inst = MainActivity.instance();
            inst.updateInbox(smsMessageStr);
        }
    }
}

Based on this tutorial site(android authority)

In your BroadcastReceiver

int yourNumber=1234567890; // your specific number

String address = smsMessage.getDisplayOriginatingAddress(); // incoming SMS number

if(address ==yourNumber){

  //display message
 }

Update

public class SmsBroadcastReceiver extends BroadcastReceiver {
 String address;
public static final String SMS_BUNDLE = "pdus";

public void onReceive(Context context, Intent intent) {
    Bundle intentExtras = intent.getExtras();

        if (intentExtras != null) {
        Object[] sms = (Object[]) intentExtras.get(SMS_BUNDLE);
        String smsMessageStr = "";
        for (int i = 0; i < sms.length; ++i) {
            String format = intentExtras.getString("format");
            SmsMessage smsMessage = SmsMessage.createFromPdu((byte[]) sms[i], format);

            String smsBody = smsMessage.getMessageBody().toString();
            address = smsMessage.getOriginatingAddress();


             smsMessageStr += "SMS From: " + address + "\n";
             smsMessageStr += smsBody + "\n";



        }
       if(address =="7911127456"){
        MainActivity inst = MainActivity.instance();
        inst.updateInbox(smsMessageStr);
      }
    }
}
}

update

   public void refreshSmsInbox() {
         ContentResolver contentResolver = getContentResolver();
         Cursor smsInboxCursor = 
    contentResolver.query(Uri.parse("content://sms/inbox"), null, null,
     null, null);
         int indexBody = smsInboxCursor.getColumnIndex("body");
         int indexAddress = smsInboxCursor.getColumnIndex("address");
         if (indexBody < 0 || !smsInboxCursor.moveToFirst()) return;
         arrayAdapter.clear();

         do {
      if(indexAddress ==7911127456){
             String str = "SMS From: " + smsInboxCursor.getString(indexAddress) +
                     "\n" + smsInboxCursor.getString(indexBody) + "\n";
             arrayAdapter.add(str);
  }
         } while (smsInboxCursor.moveToNext()); 

  //messages.setSelection(arrayAdapter.getCount() - 1);
  arrayAdapter.notifyDataSetChanged();
 }