[Java for Android App Development] clonedaccnt:
I have this search function for my app that fetches data from web server using json, everything works completely except that everytime I search something, the data keeps on appending on my listview. For example if I search for a data with an id number 7 then press search button, the data is fetched and placed on the listview which what I want, but then if I search again the id number 7, there are now 2 instances of data with an id number of 7 in the listview. What I want is to refresh the listview for every search so that the only data that will appear on the listview is the current searched data.

MainActivity.java

package learn2crack.listview;

import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.EditText;

import learn2crack.listview.library.JSONParser;

public class MainActivity extends Activity {
ListView list;
TextView title;
Button Btngetdata;
ArrayList<HashMap<String, String>> oslist = new ArrayList<HashMap<String, String>>();

//JSON Node Names
private static final String TAG_NEWS = "news";
private static final String TAG_TITLE = "title";

JSONArray android = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);
oslist = new ArrayList<HashMap<String, String>>();

Btngetdata = (Button)findViewById(R.id.getdata);
Btngetdata.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View view) {
new JSONParse().execute();
}
});
}

private class JSONParse extends AsyncTask<String, String, JSONObject> {
private ProgressDialog pDialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
title = (TextView)findViewById(R.id.title);
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Getting Data ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}

@Override
protected JSONObject doInBackground(String... args) {

JSONParser jParser = new JSONParser();

String url = "http://localhost/abc-news/news.php?json-request-news=";

EditText id = (EditText)findViewById(R.id.search_text);

url = url + id.getText().toString();

// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
return json;
}

@Override
protected void onPostExecute(JSONObject json) {
pDialog.dismiss();
try {
// Getting JSON Array from URL
android = json.getJSONArray(TAG_NEWS);
for(int i = 0; i < android.length(); i++){
JSONObject c = android.getJSONObject(i);

// Storing JSON item in a Variable
String title = c.getString(TAG_TITLE);

// Adding value HashMap key => value

HashMap<String, String> map = new HashMap<String, String>();

map.put(TAG_TITLE, title);

oslist.add(map);
list=(ListView)findViewById(R.id.list);

ListAdapter adapter = new SimpleAdapter(MainActivity.this, oslist,
R.layout.list_v,
new String[] { TAG_TITLE }, new int[] {
R.id.title });

list.setAdapter(adapter);
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(MainActivity.this, "You Clicked at "+oslist.get(+position).get("name"), Toast.LENGTH_SHORT).show();

}
});

}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}

I attached an image below to support this problem I'm encountering.