this is a login in android using HTTP,POST,JSON

LOGIN ANDROID

package com.example.situc;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.Header;
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.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.os.Bundle;
import android.app.Activity;
import android.app.ListActivity;
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 Login extends Activity {
	private EditText txt_username,txt_password;
	private Button btn_login;
	private String username,password;
	private String result;
	Login_controller login_controller = new Login_controller();
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_login);
		txt_username = (EditText)findViewById(R.id.txtUsername);
		txt_password = (EditText)findViewById(R.id.txtPassword);
		btn_login = (Button)findViewById(R.id.btnLogin);
		
		btn_login.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				
				String[] data = new String[2];
				data[0] = txt_username.getText().toString();
				data[1] = txt_password.getText().toString();
				result = login_controller.post("http://10.0.2.2:80/SITUC/index.php/welcome/login",data);
				
				try 
				{
					if(result != null)
					{
						JSONArray js = new JSONArray(result);
						if(js.length() > 0)
						{
							Log.i("lenght",String.valueOf(js.length()));
							
							
							String name = "";
							Intent statrWelcomeLayout = new  Intent(Login.this,Welcome.class);
							for(int i=0;i<js.length();i++)
							{
								 JSONObject item = js.getJSONObject(i); 
								 name = item.getString("nombre");	 
							}
							
							
							
							statrWelcomeLayout.putExtra("nombre", name);
							startActivity(statrWelcomeLayout);
							
						}
						else
						{
							Log.i("exepcion","no encontro");
						}
					}
					else
					{
						Log.i("status","error");
					}
					
					
					
				} catch (JSONException e) 
				{
					Log.i("exepcion","lanzada");
				}
			}

		});
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.login, menu);
		return true;
	}

	@Override
	protected void onPause() {
		// TODO Auto-generated method stub
		super.onPause();
		finish();
	}
	
	

}






/*HTTP HANDLER*/

package com.example.situc;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpException;
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.apache.http.util.EntityUtils;

import android.util.Log;

public class Login_controller 
{
	public String post(String url,String[] data)
	{
		String textResult = null;
		try
		{
			HttpClient httpclient = new DefaultHttpClient(); //allows do the http petition
			HttpPost post = new HttpPost(url);
			
			List<NameValuePair> itemsPost = new ArrayList<NameValuePair>();
			itemsPost.add(new BasicNameValuePair("username", data[0]));
			itemsPost.add(new BasicNameValuePair("password", data[1]));
			
			post.setEntity(new UrlEncodedFormEntity(itemsPost));
			
			HttpResponse respuesta = httpclient.execute(post);
			HttpEntity ent = respuesta.getEntity();/*y obtenemos una respuesta*/
			
			textResult = EntityUtils.toString(ent);
		}
		catch(Exception e)
		{
			
		}
		
		return textResult;
	}
}