Complex nib is slow to load

Question

I'm looking for advice about a nib that's very slow to load. It's big and complex, with lots of subviews and doodads. When I fire my UINavController to push it, it's noticeably laggy (maybe almost a second) on my 3G. It sits there with the table cell selected and nothing else happening for long enough to make you wonder if it's broken.

I wonder about pre-loading it in another thread while the user is on the previous view. I could probably fire the selector in the background with a delay in the previous view's viewDidAppear, and then keep it in a property until push time comes.

Thoughts?

Answer 1

Can you split the subviews and doodads into their own, smaller nibs? Then you don't have to load everything at the same time, just what you need for when you need it.

Answer 2

I am working on a project, which is so full of the same, it would be unusable in NIB form. I choose to start creating my own sub-views in code, and then in performance concern areas, did my own drawing (like you would in a complex/custom UITableViewCell implementation).

It isn't really that hard to create some or all of your elements in code, or roll areas of them up to something that can be drawn by hand.

Just a thought.

Answer 3

I would be careful about assuming that it is the loading of the NIB file which is slowing you down. Run Instruments and / or Shark against your application, focusing on sampling what happens when you tap on the table to bring up your new view. You might be surprised at where the bottleneck is. In particular, it might not be loading the NIB itself, but something in the initialization methods of one or more of the subviews.