How to implement ProgresDialog [Android]

I am experiencing a problem I have following code:

public void onCreate(Bundle savedInstanceState) {
    MyDialog = ProgressDialog.show(this, "Nalagam kanale" , "Prosimo počakaj ... ", true);
    MyDialog.show();
... }

Which should actually start he dialog... But the problem is that dialog is shown when everything is loaded...

How can I do solve that?

Actual code

package com.TVSpored;

import java.util.ArrayList;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;


public class Currently extends Activity{
static final int PROGRESS_DIALOG = 0;

private ArrayList<CurrentlyItem> currentItems;

private CurrentAdapter aa;
private ListView currentListView;

private JSONArray Current开发者_如何学PythonShows;
private Communicator CommunicatorEPG;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);     
    setContentView(R.layout.layout_currently);


    CommunicatorEPG = new Communicator();
    currentItems = new ArrayList<CurrentlyItem>();

    if(currentItems == null)

    int resID = R.layout.current_item;
    aa = new CurrentAdapter(this, resID, currentItems);


    currentListView = (ListView)findViewById(R.id.currentListView);

    try {
        currentListView.setAdapter(aa);
    } catch (Exception e) {
        Log.d(" * Napaka", e.toString());
    }


    try {
        populateCurrent();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}
public void populateCurrent() throws JSONException
{
    CurrentShows = CommunicatorEPG.getCurrentShows(0);

    for (int i = 0; i < CurrentShows.length(); i++) 
    {
        JSONObject jsonObject = CurrentShows.getJSONObject(i);

          String start = jsonObject.getString("1");
          Integer duration = jsonObject.getInt("2");
          String title = jsonObject.getString("3");
          String epg_channel = jsonObject.getString("4");
          String channel_name = jsonObject.getString("5");
          CurrentlyItem newItem = new CurrentlyItem(1, 2, 3, 4, 5);
          currentItems.add(i, newItem);
    }
}
}

This is actual code... I would like to do populateCurrent(); in AsyncTask and meanwhile I would like a loading screen to be shown... Have been trying for few hours now but no actual success... I have successfully shown loading screen and wen trough JSONArray, but couldn't update listview...

Thanks for support!

Expected behaviour...

Show a dialog is a typical task of UI thread, but until you complete the onCreate method, the UI thread s not free to execute the dialog creation...

Two solution: create a dialog in a separate thread or execute your long task in a separate thread.

Some highlights here: http://developer.android.com/guide/topics/ui/dialogs.html

You could wait to set the content of the activity until the you're finished with the progress dialog.

Update:

This would run your command in async-task:

new AsyncTask<Void, Void, Void> {
  protected Long doInBackground(Void... voids) {
    populateCurrent();
  }
}.execute()

However, then you probably have to make sure to update the list in the GUI thread again and in some way tell the adapter that the list have been updated (since you've given that list to the adapter):

runOnUiThread(new Runnable() {
  public void run() {
    currentItems.add(i, newItem);
    aa.notifyDataSetChanged();
  }
}

It is probably best to create a new list entirely and set the view to view that.