Question

I’m developing an Android app with a list view that contains lots of drawables.
Most of them are the same so I’m trying to use a HashMap that returns the same allocated bitmap when it’s needed but still there are lots of allocations and GC actions so that the list gets stuck from time to time when scrolling.

What can I do to optimize the performance in such case?

Caching method – loadImage Using google code

mImageWorker.loadImage(pic_url, holder.pic);
holder.*some bitmap*.setImageBitmap(Utility.getBitmap(context, id); //can be one of 5 bitmaps do I use caching with a hashMap

Answer 1

Try to use lazy loading technique using caching, you can find many tutorial on the web:

You have to see this SO thread

Also see this:

Multithreading For Performance, a tutorial by Gilles Debunne.

This is from the Android Developers Blog. The suggested code uses:

1. AsyncTasks.
2. A hard, limited size, FIFO cache.
3. A soft, easily garbage collected cache.
4. A placeholder Drawable while you download.