Java Developer meets Objective-C on Mac OS

Question

I have developed in C++ many years ago, but these days I am primarily a Java software engineer. Given I own an iPhone, am ready to spring for a MacBook next month, and am generally interested in getting started with Mac OS developmentmt (using Objective C), I thought I would just put this question out there: What Next?

More specifically, what books should I pick up, and are there any web resources that some folks could point me to? Some books that I am planning to purchase:

• Programming in Objective-C 2.0
• Cocoa(R) Programming for Mac OS X (3rd Edition)

Anyone familiar with these titles? Finally, I would be very interested in a summary of what I should be prepared to expect, once I embark on this journey. As someone that develops in Java using IntelliJ IDEA, what are some key differences I will notice as I move over to writing ObjectiveC code in Xcode? What's the differences between Mac OS desktop development and iPhone development? Being used to Java garbage collection, what should I know about ObjectiveC garbage collection / memory management. Any other language specific issues that anyone would like to point out? How about building UIs? Is it closer to Swing, building Visual C++ resource files that code interacts with, or is it more like some of the borland IDEs that will generate code for guis?

Answer 1

Having purchased both of the books in your question, I recommend Cocoa Programming for Mac OS X as a quick way to learn the language and the Cocoa framework, and is probably the fastest way to start producing real applications in Cocoa. I highly recommend it. Programming in Objective-C 2.0 is a great reference book, but if you already know C, there's no much it's going to teach you that you can't pick up from the other book. However, if you ever need to a list of all the reserved keywords in Objective-C, that's the book to go to.

All of the user interface can be generated progmatically, but you'll find it much easier to use Interface Builder, which comes with XCode, to lay out the user interface. You'll end up with a lot less code. With bindings, you can even eliminate code which isn't directly related to laying out the interface. The details are in the Cocoa Programming for Mac OS X book.

The one big thing I miss from Java is the collection API. In Cocoa, you just get NSSet, NSArray, and NSDictionary, and there's no analog to the Comparable interface. These classes are also immutable, but have mutable versions such as NSMutableArray.

I actually haven't played with the Garbage Collection in Objective-C 2.0. In previous versions of Objective-C, memory management was handled by the retain, release, and autorelease methods. Objects were created with a retain count of 1. Retaining incremented that count, releasing decremented it, and autoreleasing objects is a little more complicated. Again, the Cocoa Programming book explains it well. Garbage collection is an option, and if it's turned on, the retain, release and autorelease methods do nothing. However, if you are writing a library or framework to be used by others, you should program it as if garbage collection is turned off. That way applications can use it whether or not they have garbage collection turned on.

As for Web resources, http://cocoadevcentral.com/ is a great site with beginner tutorials. The CocoaDev Wiki at http://www.cocoadev.com/ contains detailed information on a lot of topics, and you can usually find some useful information and people on the cocoa-dev mailing list http://lists.apple.com/mailman/listinfo/cocoa-dev

iPhone development is a little different, and the details are restricted by an NDA. However, if you get approved by Apple to get access to the iPhone developer center, Apple has provided some great video overviews of the differences, which point you to the documentation you need to make the jump from Mac OS X to iPhone OS X programming.