如何在Android中将动态数据从一个活动发送到另一个活动

我正在开发一个android应用程序，我从mysql数据库中获取数据并将其显示在Listview中.我有数据类别"，例如电信，银行，社交网站等.从MySQL获得的此Category完美地显示在ListView中.现在，当我单击其中任何一个时，它应该移至下一个活动并根据该类别显示数据.假设我单击社交网站"，然后在下一个活动中，数据应该是Google Plus，Instagram，Twitter等，并且此列表将来自数据库并显示在列表视图中.我对此一无所知.. !!!请帮助我...这是我所做的代码.

I am developing an android application where I am getting data from mysql database and displaying that in Listview. I have data "Categories" like Telecom, Banking, Social Sites and so on. This Category getting from mysql, is displaying in ListView perfectly. Now when I click on any one of them, then this should move to next activity and display data according to that category. Suppose I click on Social Sites, then on next activity, the data should be Google Plus, Instagram, Twitter etc and this list will come from Database and display in listview. I am not getting any idea about this how to do that..!!! Please help me...This is my code what I've done.

Welcome.java

Welcome.java

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
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.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class Welcome extends Activity 
{
    TextView text;
    //Button b1,b2,b3;
    String CompName,CompID;

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

        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);

      //  b1=(Button)findViewById(R.id.dashboard_tab1);
      //  b1.setOnClickListener(this);

        connect();
    }

    public void connect() 
    {
        String data;
        List<String> r = new ArrayList<String>();
        ArrayAdapter<String>adapter=new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1,r);
        ListView list=(ListView)findViewById(R.id.list);
        try 
        {
                DefaultHttpClient client = new DefaultHttpClient();
                HttpGet request = new HttpGet("http://10.0.2.2/database/Retrive.php");
                HttpResponse response = client.execute(request);
                HttpEntity entity=response.getEntity();
                data=EntityUtils.toString(entity);
                Log.e("STRING", data);

                try 
                {
                   JSONArray json=new JSONArray(data);
                   for(int i=0;i<json.length(); i++)
                   {
                        JSONObject obj=json.getJSONObject(i);

                        CompName=obj.getString("fldCompName");
                        CompID=obj.getString("fldCompID");

                        Log.e("STRING", CompName);
                        Log.e("STRING",CompID);

                        r.add(CompName);
                        //r.add(CompID);
                        list.setAdapter(adapter);

                        list.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() 
                        {
                            @Override
                            public void onItemClick(AdapterView<?> parent,View view, int position, long id) 
                            {
                                Intent i1=new Intent(Welcome.this,Category1.class);
                                i1.putExtra("CompName", CompName);
                                startActivity(i1);
                            }
                        });
                   }
                } 
                catch (JSONException e) 
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            } catch (ClientProtocolException e) {
                Log.d("HTTPCLIENT", e.getLocalizedMessage());
            } catch (IOException e) {
                Log.d("HTTPCLIENT", e.getLocalizedMessage());
            }
    }

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

这是我的布局文件... !!!

This is my layout file...!!!

activity_welcome.xml

activity_welcome.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">

<ListView
    android:id="@+id/list"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/bg" >
</ListView>

</LinearLayout>

Retrive.php

Retrive.php

<?php

    $host='localhost';
    $uname='root';
    $pwd='';
    $db='database';

    $con=mysqli_connect($host,$uname,$pwd) or die("Connection Failed");
        mysqli_select_db($con,$db) or die("database selection failed");

    $sql=mysqli_query($con,"select fldCompName,fldCompID from tblCompanies where fldStatus='1'");
    while($row=mysqli_fetch_assoc($sql))
    $output[]=$row;
    $a=json_encode($output);
    print($a);
    mysqli_close();

?>