Mohammed Al-sadi Mohammed Al-sadi - 14 days ago 8
Android Question

ListView items doesn't loaded using AsyncTask

at the first I would like to thanks every one who helped me one day in this community.

I'm trying to load Listview items (downloaded from server) in my Activity. Because I'm using GingerBread I tried to do it with out AsyncTask and it works perfectly.

When I tried to do it in AsyncTask the list still empty.
Also I tried to move some parts from DoInBackground to onPostExecute and no thing changes.So could you help me.

This is my code ( UPDATED AFTER THE SECOND ANSWER )

MAIN



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.ListActivity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class StudentMSG extends ListActivity {
// url to make request
private static String url = "http://www.xxxxxxxxxxxxx?requsted=xxxxxxxxx";
// JSON Node names
private static final String TAG_CONTACTS = "contacts";
private static final String TAG_ID = "message_id";
private static final String TAG_NAME = "sender_id";
private static final String TAG_EMAIL = "title";
private static final String TAG_ADDRESS = "message_id";
private static final String TAG_GENDER = "READ";
private static final String TAG_PHONE = "message_id";
private static final String TAG_PHONE_MOBILE = "message_id";
private static final String TAG_PHONE_HOME = "message_id";
private static final String TAG_PHONE_OFFICE = "message_id";
ListView lv;
ArrayList<HashMap<String, String>> contactList ;
JSONObject json ;
ListAdapter adapter;
// contacts JSONArray
JSONArray contacts = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
load task=new load();
task.execute();





}



public class load extends AsyncTask<Void, Void , Void>
{
@Override
protected Void doInBackground(Void... params) {

// Hashmap for ListView
contactList = new ArrayList<HashMap<String, String>>();

// Creating JSON Parser instance
JSONParser jParser = new JSONParser();

// getting JSON string from URL
json = jParser.getJSONFromUrl(url);
try {
contacts = json.getJSONArray(TAG_CONTACTS);
// looping through All Contacts
for(int i = 0; i < contacts.length(); i++){
JSONObject c = contacts.getJSONObject(i);

// Storing each json item in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
String address = c.getString(TAG_ADDRESS);
String gender = c.getString(TAG_GENDER);

// Phone number is agin JSON Object


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

// adding each child node to HashMap key => value
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_EMAIL, email);
map.put(TAG_GENDER, gender);


// adding HashList to ArrayList
contactList.add(map);
}
}
catch (Exception e)
{
e.printStackTrace();
}
return null;



}
protected void onPostExecute() {

String[] s = { TAG_NAME, TAG_EMAIL , TAG_GENDER};
int[] n = {R.id.name, R.id.email , R.id.mobile };
adapter = new SimpleAdapter(StudentMSG.this, contactList,R.layout.list_item,s,n );
setListAdapter(adapter);
}
}
}


AND THIS IS THE JSON PARSER CLASS

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

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

// constructor
public JSONParser() {

}

public JSONObject getJSONFromUrl(String url) {

// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);

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

} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//"ISO-8859-1,utf-8;q=0.7,*;q=0.7"
//"iso-8859-1"
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "utf-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}

// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}

// return JSON String
return jObj;

}
}


Best Regards.

Answer

This tutorials Indicates what I want and mean .. http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/ Thanks for all participant ..