ProgressDialog in android

This is my activity code.. here I'm fetching data from the database through JSON and PHP...

How can I display a progessDialog when the data is loading?

Here is my activity code:

package org.postandget;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.*;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class main extends Activity {
    static TextView tv;
    static String text;
    ProgressDialog progressDialog;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);       
        tv  = (TextView)findViewById(R.id.textview);
        text    = "";
        tv.setText("hi parthi");                
       new main.execute();
    }

    public static void postData(Object JSONfunctions) throws JSONException{
        // Create a new HttpClient and Post Header
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://eeeee.com/ee/login.php");      
        JSONObject json = new JSONObject();
        try {
            // JSON data:           
            json.put("name", "Fahmi Rahman");
            json.put("position", "sysdev");         
            JSONArray postjson=new JSONArray();
            postjson.put(json);
            // Post the data:
            httppost.setHeader("json",json.toString());
            httppost.getParams().setParameter("jsonpost",postjson);

            // Execute HTTP Post Request
            System.out.print(json);
            HttpResponse response = httpclient.execute(httppost);
            // for JSON:
            if(response != null)
            {
                InputStream is = response.getEntity().getContent();
                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                StringBuilder sb = new StringBuilder();
                String line = null;
                try {
                    while ((line = reader.readLine()) != null) {
                        sb.append(line + "\n");
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                text = sb.toString();
            }

            tv.setTe开发者_如何学Pythonxt(text);

        }catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }
    }

    private class xyz extends AsyncTask<Void, Void, Void> {
        private final ProgressDialog dialog = new ProgressDialog(main.this);

        protected void onPreExecute() {
            this.dialog.setMessage("Please Wait...");
            this.dialog.show();
            //code which load at prefix time
            try {
               main.postData(null);          
            } catch (JSONException e) {
                e.printStackTrace();        }
        }

        @Override
        protected Void doInBackground(Void... arg0) {

                // make code which you want in background

            return null;
        }

        protected void onPostExecute(final Void unused) {
            if (this.dialog.isShowing()) {
                this.dialog.dismiss();

            }

        }
    }
}

you need to use asyncTask

AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.

An asynchronous task is defined by a computation that runs on a background thread and whose result is published on the UI thread. An asynchronous task is defined by 3 generic types, called Params, Progress and Result, and 4 steps, called onPreExecute, doInBackground, onProgressUpdate and onPostExecute

      private class xyz extends AsyncTask<Void, Void, Void> {
    private final ProgressDialog dialog = new ProgressDialog(main.this);

    protected void onPreExecute() {
        this.dialog.setMessage("Please Wait...");
        this.dialog.show();
        //code which load at prefix time

    }

    @Override
    protected Void doInBackground(Void... arg0) {

            // make code which you want in background

        return null;
    }

    protected void onPostExecute(final Void unused) {
        if (this.dialog.isShowing()) {
            this.dialog.dismiss();

        }

    }
}

and use this in your button click event or in main file ::

 new xyz().execute();

UPDATE:

package org.postandget;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.*;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class main extends Activity {
    TextView tv;
    String text;
  ProgressDialog  progressDialog;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);       
        tv  = (TextView)findViewById(R.id.textview);
        text    = "";
        tv.setText("hi parthi");                
       new main.execute();
    }
    public void postData(Object JSONfunctions) throws JSONException{
        // Create a new HttpClient and Post Header
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://eeeee.com/ee/login.php");      
        JSONObject json = new JSONObject();
        try {
            // JSON data:           
            json.put("name", "Fahmi Rahman");
            json.put("position", "sysdev");         
            JSONArray postjson=new JSONArray();
            postjson.put(json);
            // Post the data:
            httppost.setHeader("json",json.toString());
            httppost.getParams().setParameter("jsonpost",postjson);

            // Execute HTTP Post Request
            System.out.print(json);
            HttpResponse response = httpclient.execute(httppost);
            // for JSON:
            if(response != null)
            {
                InputStream is = response.getEntity().getContent();
                BufferedReader reader = new BufferedReader(new InputStreamReader(is));
                StringBuilder sb = new StringBuilder();
                String line = null;
                try {
                    while ((line = reader.readLine()) != null) {
                        sb.append(line + "\n");
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                text = sb.toString();
            }

            tv.setText(text);

        }catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
        } catch (IOException e) {
            // TODO Auto-generated catch block
        }
    }
    private class xyz extends AsyncTask<Void, Void, Void> {
        private final ProgressDialog dialog = new ProgressDialog(main.this);

        protected void onPreExecute() {
            this.dialog.setMessage("Please Wait...");
            this.dialog.show();
            //code which load at prefix time
            try {
                postData(savedInstanceState);          
            } catch (JSONException e) {
                e.printStackTrace();        }
        }

        @Override
        protected Void doInBackground(Void... arg0) {

                // make code which you want in background

            return null;
        }

        protected void onPostExecute(final Void unused) {
            if (this.dialog.isShowing()) {
                this.dialog.dismiss();

            }

        }
    }
}

First create an object of Progress Dialog in your activity like this ---->

1. ProgressDialog pd;
2. static final int Dialog_id = 1;

then within your Try block where you posting the data show the progress dialog like this ---->

1. showDialog(Dialog_id);

and after your onCreate() method create an onCreateDialog() method like this ----->

4.

 protected Dialog onCreateDialog(int id){
       switch(id){
          case Dialog_id :
            ProgressDialog pd = new ProgressDialog(this);
            pd.setTitle("Loading Data");
            pd.setCancelable(true);
            return pd;
            break;
         return null;
}