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Learn Objective C

Learn Objective C

Cocoa Dev Central: Learn Objective-C Objective-C Objective-C is the primary language used to write Mac software. If you're comfortable with basic object-oriented concepts and the C language, Objective-C will make a lot of sense. If you don't know C, you should read the C Tutorial first. This tutorial is written and illustrated by Scott Stevenson Copyright © 2008 Scott Stevenson Calling Methods To get started as quickly as possible, let's look at some simple examples. [object method]; [object methodWithInput:input]; Methods can return a value: output = [object methodWithOutput]; output = [object methodWithInputAndOutput:input]; You can call methods on classes too, which is how you create objects. id myObject = [NSString string]; The id type means that the myObject variable can refer to any kind of object, so the actual class and the methods it implements aren't known when you compile the app. In this example, it's obvious the object type will be an NSString, so we can change the type: NSString* myString = [NSString string]; Accessors

Learning Objective-C: A Primer Objective-C is the primary programming language you use when writing software for OS X and iOS. It’s a superset of the C programming language and provides object-oriented capabilities and a dynamic runtime. Objective-C inherits the syntax, primitive types, and flow control statements of C and adds syntax for defining classes and methods. It also adds language-level support for object graph management and object literals while providing dynamic typing and binding, deferring many responsibilities until runtime. At a Glance This document introduces the Objective-C language and offers extensive examples of its use. An App Is Built from a Network of Objects When building apps for OS X or iOS, you’ll spend most of your time working with objects. If you’re writing your own class, start by providing a description of the class that details the intended public interface to instances of the class. Categories Extend Existing Classes Protocols Define Messaging Contracts Blocks Simplify Common Tasks

The Objective-C Programming Language: Introduction Objective-C is the primary programming language you use when writing software for OS X and iOS. It’s a superset of the C programming language and provides object-oriented capabilities and a dynamic runtime. Objective-C inherits the syntax, primitive types, and flow control statements of C and adds syntax for defining classes and methods. It also adds language-level support for object graph management and object literals while providing dynamic typing and binding, deferring many responsibilities until runtime. At a Glance This document introduces the Objective-C language and offers extensive examples of its use. An App Is Built from a Network of Objects When building apps for OS X or iOS, you’ll spend most of your time working with objects. If you’re writing your own class, start by providing a description of the class that details the intended public interface to instances of the class. Categories Extend Existing Classes Protocols Define Messaging Contracts Blocks Simplify Common Tasks

Objective-C Objective-C source code program files usually have .m filename extensions, while Objective-C header files have .h extensions, the same as for C header files. History[edit] Objective-C was created primarily by Brad Cox and Tom Love in the early 1980s at their company Stepstone.[2] Both had been introduced to Smalltalk while at ITT Corporation's Programming Technology Center in 1981. The earliest work on Objective-C traces back to around that time.[3] Cox was intrigued by problems of true reusability in software design and programming. He realized that a language like Smalltalk would be invaluable in building development environments for system developers at ITT. However, he and Tom Love also recognized that backward compatibility with C was critically important in ITT's telecom engineering milieu.[4] Cox began writing a pre-processor for C to add some of the capabilities of Smalltalk. Popularization through NeXT[edit] Syntax[edit] Objective-C derives its object syntax from Smalltalk.

Google Objective-C Style Guide Unlike C++, Objective-C doesn't have a way to differentiate between public and private methods—everything is public. As a result, avoid placing methods in the public API unless they are actually expected to be used by a consumer of the class. This helps reduce the likelihood they'll be called when you're not expecting it. #import "GTMFoo.h" @interface GTMFoo (PrivateDelegateHandling) - (NSString *)doSomethingWithDelegate; // Declare private method @end @implementation GTMFoo (PrivateDelegateHandling) ... - (NSString *)doSomethingWithDelegate { // Implement this method } ... If you are using Objective-C 2.0, you should instead declare your private category using a class extension, for example: @interface GMFoo () { ... } which will guarantee that the declared methods are implemented in the @implementation section by issuing a compiler warning if they are not. Again, "private" methods are not really private.

C and Objective C Compared Volume Number: 13 (1997) Issue Number: 3 Column Tag: Rhapsody By Michael Rutman, independent consultant What will programming in Objective-C mean to the C++ programmer Different Object Oriented Languages Almost all of us have heard the term object oriented programming, and most of us have used C++. C++ has a very diverse syntax, many language extensions, and hundreds of quirks. On the other hand, Objective-C is a blend of C and Smalltalk. How Do I Declare an Objective-C Object? C code is the same in Objective-C and C. Classes are different between C++ and Objective C, especially in the declaration of the classes. Some things to note The Objective-C class allows a method and a variable with the exact same name. Objective-C does not respect public and private as does C++. Objective-C does not have a constructor or destructor. Objective-C uses + and - to differentiate between factory and instance methods, C++ uses static to specify a factory method. How Does an Objective-C Method Look?

35 Beautiful iPhone App Website Designs I’ve always been a fan of Apple’s design. As a web designer, I’m sure that many of you are. When Apple released the iPhone and iPod Touch, thousands of apps hit the app store. As a result, web designers started creating sites for Apple apps. These sites promote, give information about, and help sell these apps. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. iPhonevine 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. iSaid What? 30. 31. 32. 33. 34. 35. How about some feedback? I’d love to know what you thought of the sites above. Related Content About the Author

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