Connexion Android avec base de donne

package com.example.espaceenseignant;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
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 org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
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 String strURL = "http://10.0.2.2/webservice/connecter.php";
 // private String result ;
  
  private JSONArray  jArray;
  private JSONObject  json_data;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
   Button connexion = (Button) findViewById(R.id.button1);
         final EditText iden = (EditText) findViewById(R.id.editText1);
         final EditText Nom = (EditText) findViewById(R.id.editText2);
         connexion.setOnClickListener(new View.OnClickListener() {
          
             public void onClick(View v) {
              String result =null;
              InputStream is = null;
              StringBuilder sb = new StringBuilder();
              ArrayList<NameValuePair> nameValuePairs=new ArrayList<NameValuePair> ();
              nameValuePairs.add(new BasicNameValuePair("identifiant",Nom.getText().toString()));

              try{
              
      
               HttpClient httpclient = new DefaultHttpClient();
               HttpPost httppost = new HttpPost(strURL);
               httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
               HttpResponse response = httpclient.execute(httppost);
               HttpEntity entity = response.getEntity();
               is = entity.getContent();    
              }catch(Exception e){
         Log.e("log_tag", "Error in http connection " + e.toString());
        } 
        try{
         BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
       
         String line = null;
         while ((line = reader.readLine()) != null) {
          sb.append(line + "\n");
          
         }
         is.close();
         result=sb.toString();
        
              }catch(Exception e){
            Log.e("log_tag", "Error in http connection " + e.toString());
           }
        String essai=result.substring(0, 4) ;
        try {
         if (result.matches("<br >")){
           essai=result.substring(0, 2) ; 
         }
         JSONArray jArray = new JSONArray(result);
         int b=jArray.length();
         
          
                 
            JSONObject json_data = jArray.getJSONObject(0);
        
         
            String nom1 = json_data.getString("cin").toString();
            //String login = json_data.getString("login").toString();
            if (nom1.equals(iden.getText().toString()) ){
             
             Intent principale =new Intent(MainActivity.this,classe.class);
             startActivity(principale);
         
            }
            else {
             
             Toast.makeText(MainActivity.this, "nom introuvable ", Toast.LENGTH_LONG).show();
            }
         
         
          }catch(JSONException e){
         //  Log.e("log_tag", "Error parsing data " + e.toString());
           Toast.makeText(MainActivity.this, "Verifier L'identifiant ", Toast.LENGTH_LONG).show();
          }
        
       

             }
             });
  
 }
}