This document provides an introduction to developing iOS applications using Objective-C and Xcode. It outlines the necessary tools, including an Intel-based Mac and Xcode IDE. It describes downloading and registering as an Apple developer for free. It then covers the history of Objective-C and key concepts like classes, objects, variables, pointers, methods, inheritance, and common data structures like NSArray and NSDictionary. Code examples are provided to demonstrate creating classes, instantiating objects, and accessing properties and methods. Exercises are included to practice additional concepts.

1. Introduction to Objective-C Using Xcode
Dr. Thanisa Kruawaisayawan
www.imcinstitute.com

2. Start Developing iOS Applications Today
• Before you can begin writing software for iOS, you’ll need a few items.
- An Intel-based Macintosh running on Mac OS X => Mountain Lion
- Xcode (IDE: Integrated Development Environment) => 4.5.1
(Xcode 4.5.1 comes with 6.0 SDK and supports iOS 6)
• To download Xcode, you can register as an Apple developer which is for free.
Just navigate to https://developer.apple.com/programs/register/
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3. Register as an Apple Developer
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4. History of Objective-C
• 1980
• Brad Cox and Tom Love
• at Stepstone company
• created Objective-C
• 1988
• Steve Jobs (left Apple Inc.)
• at NeXT company
• licensed Objective-C from Stepstone (NS => NeXTSTEP)
• 1996
• Apple Inc.
• purchased NeXT company
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5. Variable/Pointer
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6. Variable/Pointer
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7. Object in Memory
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8. Object Oriented Concept
Class is a description of the object.
Class is not an object.
Then, how to have a dog in the program?
We have to make it up from the description !
We instantiate a dog object from a dog class
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9. Message
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10. Method
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11. Method
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12. Create a new Xcode project
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13. Mac OS X > Application > Command Line Tool
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14. Product Name: OO1_Class
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15. main.m
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16. Result
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17. New File > Mac OS X > Cocoa > Objective-C class
• Right click at OO1_Class
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18. Class Dog and Subclass of NSObject
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19. Dog.h & Dog.m
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20. Dog.h
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21. Dog.m
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22. main.m
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23. Result
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24. 24

25. Class - Accessor
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26. 26

27. Accessor - Setter
Dog.m
Dog.h
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28. main.m
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29. Result
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30. Subclass
Let’s create a SuperDog
A super dog can fly !
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31. Subclass
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32. New File > Mac OS X > Cocoa > Objective-C class
• Right click at OO1_Class
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33. Class SuperDog and Subclass of Dog
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34. SuperDog.h
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35. SuperDog.m
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36. main.m
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37. Result
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38. 38

39. SuperDog.m
• Overriding
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40. Result
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41. 41

42. 42

43. 43

44. 44

45. Dog.h (has a NSString object)
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46. main.m
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47. Exercise1
• Add setter and getter for dog’s name
• The output should look something like this:
• Add another method “eat” with one argument (NSString *), which is
the name of the food, in the Dog class. Then send message to dog
objects in the program.
• The output should look something like this:
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48. A message send
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49. Exercise2
• Create employee’s object, then show each employee’s properties,
BMI, and total income of employee in x months (x can be any
integer number). The calculation of bodyMassIndex of employee
class = 0.9*(BMI of person) when BMI of person = w/(h*h).
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50. Results
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51. @synthesize
• In dog.m, replace the implementation of the setter and getter
methods with the @synthesize construct
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52. id, self, super
• id is pointer to any objects (Notice that there is no asterisk in this
declaration, id implies the asterisk).
• self is a local variable (pointer) to object itself.
• super is used when we want to send message to itself but start
searching for method at super.
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53. Class method
• method that is executed when sending message to the class, such
as “alloc” method.
• use + instead of - in .h file to declare class method and .m to
implement
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54. NSString
• In code, you can create a literal instance of NSString like this;
NSString *lament = @"Why me!?";
• Instances of NSString can also be created programmatically using the
stringWithFormat: class method:
NSString *x = [NSString stringWithFormat:@"The best number is %d", 5];
• To get the number of characters in a string, you use the length method:
NSUInteger charCount = [x length];
• And you check to see if two strings are equal using the isEqual: method:
if ([lament isEqual:x])
NSLog(@"%@ and %@ are equal", lament, x);
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55. NSArray
• count returns the number of items in an array
• objectAtIndex: returns the pointer that the array has stored at the
index specified by the argument.
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56. for Loop
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57. Fast Enumeration
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58. NSMutableArray
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59. NSDictionary/NSMutableDictionary
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60. References
• Boonyanit Mathayomchan, Ph.D., “iPhone Application
Development (BASIC)”, 2011
• Chotipat Pornavalai, iPhone Basic #1, Mini Master of iOS
Application #1
• Aaron Hillegass, “Objective-C Programming: The Big Nerd Ranch
Guide”, 2011
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