Stupid Objective-C Mistake #1

While laying out my screen, I keep objects handy in a couple of NSArrays. Typically, I start out coding all the layouting code and retouch it once I see what's rendered on screen. Many times, objects that I try to add to my layout just do not appear - because I failed to initialize my arrays!

Since in Objective-C, a message to a nil-variable just returns nil and moves on, you dont't have any indication that something might not go according to plan. Therefore this little note to self:

First thing to do if things do not appear on screen, check your arrays initializations, stupid!

+ (void) load

I just happened run into one of those things that must happen to you if you just go out there and try to learn a new programming language from scratch without using any tutorial books.

Just for the sake of getting started with some Objective-C coding, I'm implementing some 2D animation functionality based on an animation tool coded in Java. Trying to load the files its creates using Objective-C, I implemented a method called load in one of my classes. Things got properly loaded - but, to my surprise, I also saw some error messages in the console hinting at leaking memory. An autorelease-pool was set up in my main class so I was wondering what could possibly have gone wrong.

Turns out + (void) load is method defined in NSObject class which is used for initializing objects. It got called even before my autorelease-pool was initialized, thus the leaking. Keep that in mind if you see error messages saying "No autorelease pool in place" or "Just leaking" even though an autorelease-pool is set up in your main class.