Question

This is my AsyncTask, called from getView of an adapter:

class LoadImage extends AsyncTask<Object,Void,String>{

        private ImageView imv;
        private String path;

         public LoadImage(ImageView imv) {
             this.imv = imv;

        }

         Bitmap userAvatarStream = null ;
            Bitmap IconStream = null;
            URL IconURL;

            ProgressDialog dialog;
            @Override
                protected void onPreExecute(){
                    //Setting all the variables by getting the ids from the layout


                return;

                }


                @Override
                protected String doInBackground(Object... params) {

                    try {
                        IconURL = new URL(cr.ImageUrl);
                        IconStream = BitmapFactory.decodeStream(IconURL.openConnection().getInputStream());


                    }

                    catch (MalformedURLException e){
                        e.printStackTrace();
                    }
                    catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    return null;
                }


                 protected void onPostExecute(String result){
                        // ImageView user_avatar = (ImageView)v.findViewById(R.id.follower_user_avatar);

                    imv.setImageBitmap(IconStream);


                         return;


                }

The problem that I get here is that the images keep loading. Lets say I scroll down and the images go away to be refreshed again if I scroll up the list. It keeps making calls to get the images. This behaviour is obviously undesirable except at one place that if the internet on your cell-phone goes down and comes up again, this would help to auto-load the images. But, in the current state even that is crashing as it keeps making calls. How to stop AsyncTask from doing that?

Answer 1

Just cache you images to filesystem or memory.

Each time you scroll the list getView is called. If you put the image loading method on getView and didn’t use Image Caching then it’ll download the images again and again. There are some opensource image loader for list with caching support.

One of them is droidFu. It supports two level of caching. Filesystem and memory. Get droidFu from following link.

https://github.com/kaeppler/droid-fu