Change the z-order of subviews on the iPhone

Question

I'm developing a game. I'm using about 150 UIImageView to hold the graphics. I'm simulating a 3D enviroment, so i would like to change the z-order (how close is an object to the camera).

I know there exists : [superWindow exchangeSubviewAtIndex:i withSubviewAtIndex:j];

But for some reason it's not working, some of the subviews disappear an re-appear.

Now I just remove all subviews and add it again in the correct z-order, this is ok with 50 subviews (on a 2G iphone) but with 120 it takes half a second so the gameplay sucks (I dont have and 3GS so i didn't try there).

I'm using so many subviews because each one is a square, then i colored it, resize it and move it somewhere in the screen. I'm holding the subviews under a NSMutableArray...

Answer 1

The iPhone documentation often warns about multiple UIViews nested, as it has a large performance hit after a certain point. If you start getting into issues one option is to render your UIViews into an image and using that to lower the number of on-screen views, but if you're simulating 3D that probably isn't going to help much since your composite view would need re-rendering too often.

The iPhone has full support for OpenGL ES, which allows for a real 3D environment. Take a look at some of the samples and/or a good book on the topic and you'll find that it's much easier to simply use OpenGL.