Android : WebService in Java [Android] - why code execute without any result?

Here is my sample code. It does barcodes scanning. Function sendJson should call webService. Code runs but in Apache log I see NOTHING. For some reason web service is not called. What I'm doing wrong?

package com.example.podk.scan;

import android.app.Activity;
import android.content.Intent;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicHeader;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.protocol.HTTP;
import org.json.JSONObject;
import java.io.InputStream;


public class MainActivity extends Activity implements View.OnClickListener {

private View.OnClickListener onClickListener;
private Button scanBtn;
private TextView formatTxt, contentTxt;

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
//retrieve scan result
IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
if (scanningResult != null) {
    //we have a result
    String scanContent = scanningResult.getContents();
    String scanFormat = scanningResult.getFormatName();
    formatTxt.setText("FORMAT: " + scanFormat);
    contentTxt.setText("CONTENT: " + scanContent);

    //call web service:
    sendJson("toto","foo");

}else{
    Toast toast = Toast.makeText(getApplicationContext(),
    "No scan data received!", Toast.LENGTH_SHORT);
    toast.show();
}

}

public void sendJson(final String email, final String pwd) {

    HttpClient client = new DefaultHttpClient();
    HttpConnectionParams.setConnectionTimeout(client.getParams(), 10000); //Timeout Limit
    HttpResponse response;
    JSONObject json = new JSONObject();

    try {
        String WS_URL = "http://192.168.88.171:8080/test/test.php";
        HttpPost post = new HttpPost(WS_URL);
        json.put("email", email);
        json.put("password", pwd);
        StringEntity se = new StringEntity( json.toString());
        se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
        post.setEntity(se);
        response = client.execute(post);

        /*Checking response */
        if(response!=null){
            InputStream in = response.getEntity().getContent(); //Get the data in the entity
        }

    } catch(Exception e) {
        e.printStackTrace();
    }
}

public void onClick(View v){
//respond to clicks
if(v.getId()==R.id.scann_button){
    //scan
    IntentIntegrator scanIntegrator = new IntentIntegrator(this);
    scanIntegrator.initiateScan();
}
}

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

scanBtn = (Button)findViewById(R.id.scann_button);
formatTxt = (TextView)findViewById(R.id.scan_format);
contentTxt = (TextView)findViewById(R.id.scan_content);
//uaktywnij aktywnosc na przyciskanie
scanBtn.setOnClickListener(this);
}


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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
    return true;
}

return super.onOptionsItemSelected(item);
}
}