Question

I am a beginner in android.I have built an application for login for leave module.For connecting it with mySql through PHP..I tried this code from a website.

package com.example.axdroid;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class Axdroid extends Activity {
Button b;
EditText et,pass;
TextView tv;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
List<NameValuePair> nameValuePairs;
ProgressDialog dialog = null;

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_axdroid);

    b = (Button)findViewById(R.id.Button01); 
    et = (EditText)findViewById(R.id.username);
    pass= (EditText)findViewById(R.id.password);
    tv = (TextView)findViewById(R.id.tv);

    b.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {

            dialog = ProgressDialog.show(Axdroid.this, "",
                   "Validating user...", true);
            Intent i=new Intent(getApplicationContext(),Userpage.class);
             startActivity(i);                
             new Thread(new Runnable() {
                    public void run() {
                        login();                         
                    }
                  }).start();         

        }
        });}
void login(){
    try{           

        httpclient=new DefaultHttpClient();
        httppost= new HttpPost("http://192.168.1.222/AndroidLeave/check.php");
        //add your data
        nameValuePairs = new ArrayList<NameValuePair>(2);
        // Always use the same variable name for posting i.e the android side variable name and php side variable name should be similar,
        nameValuePairs.add(new BasicNameValuePair("username",et.getText().toString().trim()));  // $Edittext_value = $_POST['Edittext_value'];
        nameValuePairs.add(new BasicNameValuePair("password",pass.getText().toString().trim()));
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        //Execute HTTP Post Request
        response=httpclient.execute(httppost);
        // edited by James from coderzheaven.. from here....
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        final String response = httpclient.execute(httppost, responseHandler);
        System.out.println("Response : " + response);
        runOnUiThread(new Runnable() {
            public void run() {
                tv.setText("Response from PHP : " + response);
                dialog.dismiss();
            }
        });

        if(response.equalsIgnoreCase("User Found")){
            runOnUiThread(new Runnable() {
                public void run() {
                    Toast.makeText(Axdroid.this,"Login Success", Toast.LENGTH_SHORT).show();
                }
            });

            startActivity(new Intent(getApplicationContext(), Userpage.class));
        }else{
            showAlert();               
        }

    }catch(Exception e){
        dialog.dismiss();
        System.out.println("Exception : " + e.getMessage());
    }
}
public void showAlert(){
    Axdroid.this.runOnUiThread(new Runnable() {
        public void run() {
            AlertDialog.Builder builder = new AlertDialog.Builder(Axdroid.this);
            builder.setTitle("Login Error.");
            builder.setMessage("User not Found.") 
                   .setCancelable(false)
                   .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                       public void onClick(DialogInterface dialog, int id) {
                       }
                   });                    
            AlertDialog alert = builder.create();
            alert.show();              
        }
    });
}

}

I am unable to make this work as while debugging the code…the control jumps from httpclient to catch code.Would appreciate any help in sorting this.

This is the PHP file.I have checked it seperately and it is working.

<?php
$hostname_localhost ="localhost";
$database_localhost ="mydatabase";
$username_localhost ="root";
$password_localhost ="";
$localhost = mysql_connect($hostname_localhost,$username_localhost,$password_localhost)
or
trigger_error(mysql_error(),E_USER_ERROR);

mysql_select_db($database_localhost, $localhost);


$username = $_POST['username'];
$password = $_POST['password'];


$query_search = "select * from tbl_user where username = '".$username."' AND password = '".$password. "'";
$query_exec = mysql_query($query_search) or die(mysql_error());
$rows = mysql_num_rows($query_exec);
//echo $rows;
if($rows == 0) {
echo "No Such User Found";
}
else  {
echo "User Found";
}
?>

@ashwani
This is the present Axdroid.java page(main activity page)

public class Axdroid extends Activity {
Button b;
EditText et,pass;
TextView tv;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
List<NameValuePair> nameValuePairs;
ProgressDialog dialog = null;

@Override
public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_axdroid);

    b = (Button)findViewById(R.id.Button01); 
    et = (EditText)findViewById(R.id.username);
    pass= (EditText)findViewById(R.id.password);
    tv = (TextView)findViewById(R.id.tv);

    b.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {

            String url="http://192.168.1.222/AndroidLeave/check.php";
            JSONParser jparser= new JSONParser();
            ArrayList<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("tag", "getcategory"));
            params.add(new BasicNameValuePair("username", et.getText().toString()));
            params.add(new BasicNameValuePair("password", pass.getText().toString()));
            JSONObject jObj= jparser.makeHttpRequest(url, "POST", params);try {
                String success = jObj.get("success").toString();
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }               


        }
        });}'

Answer 1

for parsing the data I use the following class

JsonParser.java

public class JSONParser {

    InputStream is = null;
    JSONObject jObj = null;
    String json = "";

    public JSONParser() {
    }

    // function get json from url
    // by making HTTP POST or GET method
    public JSONObject makeHttpRequest(String url, String method,
            List<NameValuePair> params) {

        // Making HTTP request
        try {

            // check for request method
            if (method == "POST") {
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            } else if (method == "GET") {
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "UTF-8"), 8);
            StringBuilder sb = new StringBuilder("");

            Log.d("reader value in json parser", reader.toString());
            String line = "";
            while ((line = reader.readLine()) != null) {
                Log.d("line in JsonParser", line);
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
            Log.d("Json value", json);

        } catch (Exception e) {
            Log.d("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {

            jObj = new JSONObject(json);
            json = "";
        } catch (JSONException e) {
            Log.d("JSON Parser", "Error parsing data " + e.toString());
        }
        return jObj;
    }
}

now in your activity try to pass a url like this

String url="place your url here";
JSONParser jparser= new JSONParser();
params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", "getcategory"));
params.add(new BasicNameValuePair("username", username.getText().toString()));
params.add(new BasicNameValuePair("password", password.getText().toString()));
JSONObject jobj= jparser.makeHttpRequest(url, "POST", params); 

//now here retrieve the data from json as:

String success= jobj.get("success");

Hope this helps!

also in your php file you have to use the json_encode function before echo !