listview ImageView slow performance

Question

I have a ListView that is populate by taking photos. Each time I take a photo, the photo gets added as an ImageView entry to the listview, together with the date etc. When the photo is taken, the Uri is saved into an arraylist in memory and when the listview is displayed, it loads the images for the rows from the arraylist uris into bitmaps (scaled down) and then into drawables for the imageviews. Everything works fine, however, when the listview gets longer, it gets really slow and sometimes I get an out of memory on byte allocation error.

Here is where I populate the view for the listview in my own custom adapter:

public View getView(int position, View convertView, ViewGroup parent)
    {
        Uri selectedImage2 = Uri.parse(sampleuris.get(position).toString());

        Bitmap ThumbImage = null;

        if(convertView == null)
        {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView  = inflater.inflate(R.layout.row_list_sample_entry, parent , false);

        }

        ImageView sampleimage   = (ImageView)     convertView.findViewById(R.id.sampleimage);

        if(ThumbImage == null)
        {

             try
              {
                  ThumbImage = ThumbnailUtils.extractThumbnail(decodeUri(selectedImage2), 100, 100);
              }
              catch (FileNotFoundException ex)
              {
                  Logger.getLogger(Screen_View_Package.class.getName()).log(Level.SEVERE, null, ex);
              }

             Drawable d = new BitmapDrawable(null, ThumbImage);
             sampleimage.setImageDrawable(d);
        }
        else
        {
            Drawable d = new BitmapDrawable(null, ThumbImage);
            sampleimage.setImageDrawable(d);
        }

            TextView position2      = (TextView)      convertView.findViewById(R.id.packageimage2);
            TextView datereceived   = (TextView)      convertView.findViewById(R.id.date);


            position2.setText(""+(position+1));
            datereceived.setText(sampledates.get(position));
            //textSynced.setText("Synced: "+syncs.get(position));



            return convertView;
      }
    //----------------------------------------

Answer 1

I have fixed the problem by converting the bitmap images to byte arrays before the listview populates and then for the listview, I just use the bytearray which is stored in memory to create drawable and display them. No Memory errors. Heres the new code for the listview's getview :

public View getView(int position, View convertView, ViewGroup parent)
    {
        //Uri selectedImage2 = Uri.parse(sampleuris.get(position).toString());

        //Bitmap ThumbImage = null;

        if(convertView == null)
        {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView  = inflater.inflate(R.layout.row_list_sample_entry, parent , false);

        }

        ImageView sampleimage   = (ImageView)     convertView.findViewById(R.id.sampleimage);

        byte[] b = Base64.decode(sampleuris.get(position),Base64.DEFAULT);
        ByteArrayInputStream is = new ByteArrayInputStream(b);
        Drawable d = Drawable.createFromStream(is, "bloodsample");
        sampleimage.setImageDrawable(d);

            TextView position2      = (TextView)      convertView.findViewById(R.id.packageimage2);
            TextView datereceived   = (TextView)      convertView.findViewById(R.id.date);


            position2.setText(""+(position+1));
            datereceived.setText(sampledates.get(position));
            //textSynced.setText("Synced: "+syncs.get(position));



            return convertView;
      }