Improve ListView efficiency when loading images from SD into the ListView

Question

I am using a custom adapter for my ListView as per the efficient adapter sample by Romain Guy.

In the getView() method of my adapter I am assigning an ImageView a jp

Answer 1

Rather than loading the images from within the list adapter on demand how about kicking off a thread from the onCreate of your activity to load images? As each image loads you can fire a callback to the activity to display the image in the list. The callback method would be something along the lines of:

void onImageDownloadComplete(int pos, BitMap bm) {
    ListView lv = getListView();
    View listItem = lv.getChildAt(pos);
    ImageView img = (ImageView)listItem.getChildAt(indexOfIcon);
    img.setImageBitmap(bm);
}

Answer 2

Images need to be processed in background thread. Recycled views need to be taken into account. I try to address all these issues in my sample code, it works fine now, you may take a look Lazy load of images in ListView