Tricks for improving iPhone UITableView scrolling performance?

Question

I have a uitableview that loads fairly large images in each cell and the cell heights vary depending on the size of the image. Scrolling performance is decent, but can sometimes be jerky.

I found these tips I found on the FieryRobot blog:

glassy-scrolling-with-uitableview

more-glassy-scrolling-with-uitableview

Does anyone have any tips for improving uitableview scrolling performance?

Answer 1

1. Cache the height of the rows (the table view can request this frequently)
2. Create a least-recently-used cache for the images used in the table (and invalidate all the inactive entries when you receive a memory warning)
3. Draw everything in the UITableViewCell's drawRect: if possible avoid subviews at all costs (or if you require the standard accessibility functionality, the content view's drawRect:)
4. Make your UITableViewCell's layer opaque (same goes for the content view if you have one)
5. Use the reusableCellIdentifier functionality as recommended by the UITableView examples/documentation
6. Avoid gradients/complicated graphical effects that aren't pre-baked into UIImages