Objective-C或Cocoa First

Question

I am new to Mac/iOS development. I am coming over from C# .net. My question is should I read on Objective-C first or Cocoa? I don't want to buy two books and start reading one and find out I should have only got one book and read it. Thanks Curtis

Answer 1

看看如何使用Objective-C构建Cocoa框架，学习语言是合乎逻辑的第一步。

Answer 2

You don't need to become fluent in the language, to the point of exchanging implementations and dispatching blocks like nobody's business, all before you learn the frameworks. Indeed, such an undertaking would be folly.

At the same time, you can't learn Cocoa without a firm grasp of OOP, dynamic dispatch (messaging), MVC, and other important concepts. Some of these underlie Objective-C, some are part of Objective-C, and some are separate from Objective-C.

I say start learning those concepts, including the basic portions of the language, and then pick up the framework before you get too far into it. Like Regexident said in their comment on one of the other answers, you pretty much can't practice Objective-C without using Cocoa anyway, so it won't be long before you need to start into the framework to in order to practice the language—at which point you'll be practicing with both.

Relevant Apple documentation:

• Object-Oriented Programming with Objective-C
• Learning Objective-C: A Primer
• Cocoa Fundamentals Guide
• The (full, gory details of the) Objective-C Programming Language

If you don't already know C, start there. As with Objective-C, you don't need to become a full-blown C guru, but you do need to understand pointers, declarations vs. statements, how function calls work, the differences between the primitive types, and other basic concepts.

Answer 3

Objective-C is just a superset of C. All the Cocoa books that I've seen introduce Objective-C in the first part and then go on to describe how to use the frameworks. I'd recommend just getting a Cocoa book, just leaf through it and make sure the Objective-C primer in it is meaty enough for you.

Answer 4

I believe there is a lot of good information in the various answers here (especially @Peter Hosey's), but I do want to make sure we're not confusing the OP.

You can't practically learn ObjC without learning Cocoa today. It's like learning C# without learning .NET. You absolutely should focus very early on the patterns and underlying concepts of Cocoa (like MVC, as PH notes). But you'll get that best by working through things that teach you practical iOS or Mac development techniques rather than working through something that tries to provide a more "pure ObjC" experience such as writing command-line apps (though even Foundation is part of Cocoa, so even then you can't escape it).

The key lesson here is that I recommend new students focus on resources that teach them the whole process they need to develop for iOS or OS X. It's worth learning Xcode, ObjC, and Cocoa(Touch) together, along with MVC, target/selector, and the other critical patterns, rather than trying to take them one at a time.

PH is absolutely correct that you don't need to learn all of ObjC in one go. You can do a lot of development and never use blocks or KVO for instance. (That may change in future versions of iOS, but it's still true today.)