Android AsyncTask update ListView notifyDataSetChanged when Items Load finish

package com.myapp;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;


public class MainActivity extends Activity  {
    
    private ListView lstView;
    private ImageAdapter imageAdapter;
    
    ArrayList<HashMap<String, Object>> MyArrList = new ArrayList<HashMap<String, Object>>();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);        
        // ProgressBar
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        
        setContentView(R.layout.activity_main);

        // ListView and imageAdapter
    	lstView = (ListView) findViewById(R.id.listView1);
    	lstView.setClipToPadding(false);
        imageAdapter = new ImageAdapter(getApplicationContext()); 
        lstView.setAdapter(imageAdapter);

        setProgressBarIndeterminateVisibility(true); 
        new LoadContentFromServer().execute();

    }


    class LoadContentFromServer extends AsyncTask<Object, Integer, Object> {
        
        @Override
        protected Object doInBackground(Object... params) {

        	
        	String url = "https://www.thaicreate.com/android/getJSON.php";
        	
          	JSONArray data;
    			try {
    				data = new JSONArray(getJSONUrl(url));
    				
    		    	MyArrList = new ArrayList<HashMap<String, Object>>();
    				HashMap<String, Object> map;
    				
    				for(int i = 0; i < data.length(); i++){
    	                JSONObject c = data.getJSONObject(i);
    	    			map = new HashMap<String, Object>();
    	    			map.put("ImageID", (String)c.getString("ImageID"));
    	    			map.put("ImageName", (String)c.getString("ImageName"));
    	    			
    	    			// Thumbnail Get ImageBitmap To Object
    	    			map.put("ImagePathThum", (String)c.getString("ImagePath_Thumbnail"));
    	    			Bitmap newBitmap = loadBitmap(c.getString("ImagePath_Thumbnail"));
    	    			map.put("ImageThumBitmap", newBitmap);
    	    			
    	    			// Full (for View Popup)
    	    			//map.put("ImagePathFull", (String)c.getString("ImagePath_FullPhoto"));

    	    			MyArrList.add(map);
    	    			
    	    			publishProgress(i);
    	    				
    				}
    	    		
    				
    			} catch (JSONException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
 
            return null;
        }

        @Override
        public void onProgressUpdate(Integer... progress) {
        	imageAdapter.notifyDataSetChanged();
        }
        
        @Override
        protected void onPostExecute(Object result) {
            setProgressBarIndeterminateVisibility(false); // When Finish
        }
    }	
  	
	 
    class ImageAdapter extends BaseAdapter {

        private Context mContext; 

        public ImageAdapter(Context context) { 
            mContext = context; 
        } 

        public int getCount() { 
            return MyArrList.size();    
        } 

        public Object getItem(int position) { 
            return MyArrList.get(position); 
        } 

        public long getItemId(int position) { 
            return position; 
        } 

		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			
			LayoutInflater inflater = (LayoutInflater) mContext
					.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
		 
			 
			if (convertView == null) {
				convertView = inflater.inflate(R.layout.activity_column, null); 
			}
			
			// ColImage
			ImageView imageView = (ImageView) convertView.findViewById(R.id.ColImgPath);
			imageView.getLayoutParams().height = 80;
			imageView.getLayoutParams().width = 80;
			imageView.setPadding(5, 5, 5, 5);
			imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        	 try
        	 {
        		 imageView.setImageBitmap((Bitmap)MyArrList.get(position).get("ImageThumBitmap"));
        	 } catch (Exception e) {
        		 // When Error
        		 imageView.setImageResource(android.R.drawable.ic_menu_report_image);
        	 }
        	
			// ColImgID
			TextView txtImgID = (TextView) convertView.findViewById(R.id.ColImgID);
			txtImgID.setPadding(10, 0, 0, 0);
			txtImgID.setText("ID : " + MyArrList.get(position).get("ImageID").toString());
			
			// ColImgName
			TextView txtPicName = (TextView) convertView.findViewById(R.id.ColImgName);
			txtPicName.setPadding(50, 0, 0, 0);
			txtPicName.setText("Name : " + MyArrList.get(position).get("ImageName").toString());	
		 
			return convertView;
				
		}
        
    }
    
    /*** Get JSON Code from URL ***/
  	public String getJSONUrl(String url) {
  		StringBuilder str = new StringBuilder();
  		HttpClient client = new DefaultHttpClient();
  		HttpGet httpGet = new HttpGet(url);
  		try {
  			HttpResponse response = client.execute(httpGet);
  			StatusLine statusLine = response.getStatusLine();
  			int statusCode = statusLine.getStatusCode();
  			if (statusCode == 200) { // Download OK
  				HttpEntity entity = response.getEntity();
  				InputStream content = entity.getContent();
  				BufferedReader reader = new BufferedReader(new InputStreamReader(content));
  				String line;
  				while ((line = reader.readLine()) != null) {
  					str.append(line);
  				}
  			} else {
  				Log.e("Log", "Failed to download file..");
  			}
  		} catch (ClientProtocolException e) {
  			e.printStackTrace();
  		} catch (IOException e) {
  			e.printStackTrace();
  		}
  		return str.toString();
  	}

  	/***** Get Image Resource from URL (Start) *****/
	private static final String TAG = "Image";
	private static final int IO_BUFFER_SIZE = 4 * 1024;
	public static Bitmap loadBitmap(String url) {
	    Bitmap bitmap = null;
	    InputStream in = null;
	    BufferedOutputStream out = null;

	    try {
	        in = new BufferedInputStream(new URL(url).openStream(), IO_BUFFER_SIZE);

	        final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
	        out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);
	        copy(in, out);
	        out.flush();

	        final byte[] data = dataStream.toByteArray();
	        BitmapFactory.Options options = new BitmapFactory.Options();
	        //options.inSampleSize = 1;

	        bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,options);
	    } catch (IOException e) {
	        Log.e(TAG, "Could not load Bitmap from: " + url);
	    } finally {
	        closeStream(in);
	        closeStream(out);
	    }

	    return bitmap;
	}

	 private static void closeStream(Closeable stream) {
	        if (stream != null) {
	            try {
	                stream.close();
	            } catch (IOException e) {
	                android.util.Log.e(TAG, "Could not close stream", e);
	            }
	        }
	    }
	 
	 private static void copy(InputStream in, OutputStream out) throws IOException {
        byte[] b = new byte[IO_BUFFER_SIZE];
        int read;
        while ((read = in.read(b)) != -1) {
            out.write(b, 0, read);
        }
    }
	/***** Get Image Resource from URL (End) *****/

}