Android中ListView使用- 网络图片的异步加载

public void setViewImage(ImageView v, String value) {  
    new ImageDownloadTask().execute(value, v);  
}  
private class ImageDownloadTask extends AsyncTask<Object, Object, Bitmap>{  
        private ImageView imageView = null;  
        @Override  
        protected Bitmap doInBackground(Object... params) {  
            // TODO Auto-generated method stub  
           Bitmap bmp = null;  
            imageView = (ImageView) params[1];  
            try {  
                bmp = BitmapFactory.decodeStream(new URL((String)params[0]).openStream());  
            } catch (MalformedURLException e) {  
               // TODO Auto-generated catch block  
                e.printStackTrace();  
            } catch (IOException e) {  
                // TODO Auto-generated catch block  
                e.printStackTrace();  
            }  
            return bmp;  
        }  
         
       protected void onPostExecute(Bitmap result){  
           imageView.setImageBitmap(result);  
        }  
   }