AsyncTask<String, Void, Bitmap>的调用，请问如下代码的调用？

public class MYTask extends AsyncTask {
/**
* 表示任务执行之前的操作
*/
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
dialog.show();
}

    /**
     * 主要是完成耗时的操作
     */
    @Override
    protected Bitmap doInBackground(String... arg0) {
        // TODO Auto-generated method stub
        // 使用网络连接类HttpClient类王城对网络数据的提取
        HttpClient httpClient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(arg0[0]);
        Bitmap bitmap = null;
        try {
            HttpResponse httpResponse = httpClient.execute(httpGet);
            if (httpResponse.getStatusLine().getStatusCode() == 200) {
                HttpEntity httpEntity = httpResponse.getEntity();
                byte[] data = EntityUtils.toByteArray(httpEntity);
                bitmap = BitmapFactory
                        .decodeByteArray(data, 0, data.length);
            }
        } catch (Exception e) {
            // TODO: handle exception
        }
        return bitmap;
    }

    /**
     * 主要是更新UI的操作
     */
    @Override
    protected void onPostExecute(Bitmap result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        imageView.setImageBitmap(result);
        dialog.dismiss();
    }

}

http://blog.csdn.net/easy_gemini/article/details/8219942

你那里不理解，你可以看下AsyncTask的基本使用