Working with many interface elements in Cocoa.

Question

Hi,

My app requires an interface that has many buttons, text fields and matrixes. And they need to change from time to time. Right now I do this by having all elements in IB already and hiding/showing/moving them when needed. What would others recommend? Should I do that? Should I use an NSTabView? NSView? Should create the elements programatically? If so, what if I have an element that is already created that I need again without changes? It would be a waste of releasing it and creating it again.

Any help would be greatly appreciated.

Answer 1

Your current approach sounds fine. If you're showing/hiding them but otherwise they remain unchanged, why go through the trouble of creating them with code, when your XIB keeps a "freeze-dried" copy of exactly what you need already?

As long as you're keeping them within logical groups, you can just move/swap/show/hide the group's container (like NSBox or an NSView). If you have a LOT of logical groups, which aren't always shown every session, you can separate them out into their own XIBs and only load them when they're needed, to save launch time and memory.

If you use NSViewController, it's even better because you can make clean breaks for each logical group. Load the panel as the view and the view controller will keep outlets/actions and has a one-to-one relationship with a xib.

Answer 2

In my opinion, it's better to create interfaces programmatically if you have to animate views around a lot. If it's just a matter of hiding/unhiding them, IB works great, but if you need re-layout or create unknown numbers of views dynamically it's not worth trying to make it all work with nib files.

As for general advice:

• Create subclasses (from UIView or UIControl or one of their subclasses) for every kind of element you're going to use. It's tempting to piece together composite views from your UIViewController, but you'll really be much better off creating real classes.

• Study the standard Cocoa view classes, and try to create similar API:s in your own controls and views.

• Put as much data (sub-element positioning etc) into a plist, so that you can easily change it from one centralized place instead of having to dig around in the code.

If you are often creating several dozen short-lived views, it's worth keeping them in a pool and reusing them. But if it's just a few labels being added and removed intermittently I wouldn't worry too much about it. As usual: don't optimize too early.