数据插入使用PHP SQL &Android应用程序

我已经创建了一个应用程序连接PHP, Mysql &Android。我正在插入名称，价格&;描述。布局很好，id给出完美，但数据没有插入SQL DB。

package com.oplo.user.demo2;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
/**
 * Created by user on 6/2/2015.
 */
@SuppressWarnings("deprecation")
public class addRecord extends Activity {
    @SuppressLint("NewApi")
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add);
        if(android.os.Build.VERSION.SDK_INT  > 9)
        {
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);
        }
        final EditText txtA = (EditText) findViewById(R.id.txtA);
        final EditText txtB = (EditText) findViewById(R.id.txtB);
        final EditText txtC = (EditText) findViewById(R.id.txtC);
        final Button getData = (Button) findViewById(R.id.btnSave);
        final Button btnBack = (Button) findViewById(R.id.btnBack);
        btnBack.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Intent i = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(i);
            }
        });
        getData.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                if(txtA.getText().length()<2){
                    Toast.makeText(getApplicationContext(), "Input Name", Toast.LENGTH_LONG).show();
                }if(txtB.getText().length()<2){
                    Toast.makeText(getApplicationContext(), "Input Price", Toast.LENGTH_LONG).show();
                }if(txtC.getText().length()<2){
                    Toast.makeText(getApplicationContext(), "Input Description", Toast.LENGTH_LONG).show();
                }else{
                    String url = "http://www.xyz.in/demo.php";
                    List params = new ArrayList();
                    //noinspection deprecation
                    params.add(new BasicNameValuePair("strA", txtA.getText().toString()));
                    params.add(new BasicNameValuePair("strB", txtB.getText().toString()));
                    params.add(new BasicNameValuePair("strC", txtC.getText().toString()));
                    @SuppressWarnings("unused")
                    String resultServer  = getHttpPost(url,params);
                    //result.setText(resultServer);
                    Toast.makeText(addRecord.this, "1 Record inserted...", Toast.LENGTH_LONG).show();
                    emtyText();
                    txtA.requestFocus();
                }
            }
            public void emtyText(){
                txtA.setText("");
                txtB.setText("");
                txtC.setText("");
            }
        });
    }
    public String getHttpPost(String url,List params) {
        StringBuilder str = new StringBuilder();
        HttpClient client = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);
        try {
            httpPost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
            HttpResponse response = client.execute(httpPost);
            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            if (statusCode == 200) { // Status OK
                HttpEntity entity = response.getEntity();
                InputStream content = entity.getContent();
                BufferedReader reader = new BufferedReader(new InputStreamReader(content));
                String line;
                while ((line = reader.readLine()) != null) {
                    str.append(line);
                }
            } else {
                Log.e("Log", "Failed to download result..");
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return str.toString();
    }
}

<?php
$host = "localhost";
	$user = "xcxc";
	$pass = "xcxc";
	$database = "xcxc";
	
	$con = mysql_connect($host, $user, $pass) or die("Cannot connect Database");
	mysql_select_db($database) or die("Cannot select Database.");
	
	$a = $_POST["strA"];
	$b = $_POST["strB"];
	$c = $_POST["strC"];
	
	$sql = "INSERT INTO demo (name, price, description) VALUES('$a', '$b', '$c')";
	$result = mysql_query("SET NAMES 'UTF8'", $con);
	$result = mysql_query($sql, $con);
	if(!$result){
		die ('Error: '.mysql_error($con));
	}
	//echo "1 record added...";
	mysql_close($con);

这是我的代码，但是数据没有插入到SQL中。

请让我知道这段代码的问题在哪里。