Objective-C survives as the primary programming language for Apple platforms like macOS and iOS. It is a superset of C that adds object-oriented capabilities inspired by Smalltalk like classes, methods, and dynamic typing. Objective-C code is typically compiled to bytecode using LLVM and works with Apple's Cocoa frameworks. It has been supported on Apple platforms since the 1980s and remains an important part of development for iOS apps and Mac software.

1. Objective-C Survives
Shumpei Akai

2. Objective-C
• Objective-C == C + (Smalltalk
)OOP
• C++ == C + Chaos

3. Objective-C
• C
• Objective-C++
•
• Ruby
• OK
•

4. • 3
•
•
•
• C

5. • Objective-C
• Cocoa

6. •
• gcc
• clang (LLVM )
• “.m”

7. •
• mac XCode
•
• Cocoa (mac) / Cocoa Touch (iOS)
• GNUStep ( )

8. Objective-C
• 1983: Brad Cox (C++ )
• 1988: NeXT ( )
• 1995: NeXT
• 1996: Apple NeXT
• 2001: Mac OS X
• 2007: Objective-C 2.0

10. •
//
[str length]
// 1
[array objectAtIndex:0]
// 2
[array insertObject: obj atIndex: 2]

11. •
• Ruby Lisp
• “insertObject:atIndex:”
• “objectAtIndex:”

12. •
• stringByAppendingString:
•
• setObject:forKey:
•

13. •
•
•
•

15. id :

17. ※
Objective-C

18. • ClassName* OK
•
• id
•

19. nil
• (id )
• null
• nil
• 0/NULL/nil
•

20. NSMutableArray *array =
[NSMutableArray arrayWithObjects: @"one",
@"two”, nil];
NSArray *newAdditions =
[NSArray arrayWithObjects: @"3", @"4", @"5",
nil];
[arry addObjectsFromArray: newAdditions];

21. BOOL
•
• C++/C99
• YES/NO

22. • (.h)
@interface ClassName : SuperClassName {
id instanceVariable;
}
- (void)instanceMethod;
+ (id)classmethod;
@end

23. • (.m)
@implementation ClassName
- (void)instanceMethod{
//
}
+ (id)classmethod{
//
}
@end

24. • (java.lang.Object
)
•
• Cocoa NSObject
•

25. • java
•
• 2 prefix
• apple NS (== NeXT Step)
•

26. • - (void)instanceMethodWithArg:(id)arg{ }
• Java
• self
•

27. • obj->instanceVar
• ( )
• self
• @public, @protected, @private
• @protected ( )

28. • + (void)classMethodWithArg:(id)arg{ }
•
• [ClassName methodName]

29. • [ClassName class]
•
• ==
• [ClassName foo] == [[ClassName class] foo]

30. •
• static

31. •

32. +alloc +allocWithZone:
•
• Cocoa
•
•

33. - init
• [[NSObject alloc] init]
•
• init
-(id) init{
self = [super init];
if(self){
//
}
return self;
}

34. alloc init
•
•
• ?
•
•

35. Cocoa
•
•
• free retain(+1)
• release(-1)
• 0

36. • caller
• alloc,new,copy,mutableCopy
• +1
-(void) doFoo{
NSString* str=[[NSString alloc] init] ;
//
[str release]; //
}

37. •
•
- (void)doBarWithArray:(NSArray*)ary{
id obj=[ary objectAtIndex:0];
//ary obj release
}

38. retain
• /
retain
•
- (void)doBarWithArray:(NSArray*)ary{
self->ary = [ary retain];
}

39. release
• release
• nil
- (void)didReceiveMemoryWarning{
[self->data release];
self->data = nil; //data free
}

40. • caller
• caller free
-(NSString*) makeString{
return [[NSString alloc] init] ;
//caller release
}
-(NSString*) makeString{
return [[[NSString alloc] init] release];
//return
}

41. autorelease
• release
• release
• obj
-(NSString*) makeString{
return [[[NSString alloc] init] autorelease];
//
}

42. AutoreleasePool
• autorelease
• => release
•
- (void)foo{
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
//do something
[pool release];
}

43. dealloc
• 0
• obj
release
-(void) dealloc{
[self->str release];
[self->ary release];
[super dealloc];
}

44. •
• Cocoa
•
• retain
• retain

45. • Java interface
• optional OK
@protocol HogeProtocol <SuperProtocol>
-(BOOL)isCharactor;
-(BOOL)isDisplay;
-(void)start;
-(void)abort;
-(BOOL)step;
@optional
-(void)callbackWithData:(NSData*)data;
@end

46. • Java
• id<FooProtocol> : FooProtocol
• BarClass<FooProtocol>* : BarClass
FooProtocol

47. •
@implementation ClassName(CategoryName)
- (void)addingMethod{
//
}
@end

48. • obj.proptyName
•
@interface ClassName : NSObject {
}
@property (nonatomic,retain) id prop; @implementation ClassName
@end @synthesize prop;
@end

49. • NSObject
• ?
• - (BOOL)respondsToSelector:(SEL)aSelector
•
• - (id)performSelector:(SEL)aSelector
• - (id)performSelector:(SEL)aSelector withObject:(id)anObject
• - (id)performSelector:(SEL)aSelector withObject:(id)anObject
withObject:(id)anotherObject

50. (cont.)
•
• - (IMP)methodForSelector:(SEL)aSelector
•
• Class NSClassFromString(NSString *aClassName);

51. •
• NSString
• @”hoge”;
• NSMutableString
• Cocoa mutable immutable

52. • NSArray/NSMutableArray
• :
• [NSMutableArray arrayWithObjects:@”one”,
@”two”,nil]
• Cocoa
• nil

53. /
•
• NSDictionary/NSMutableDictionary
•
• NSSet/NSMutableSet

54. • NSValue
• C
• NSNumber
•
• 1
• [NSNumber numberWithBool:YES]
• [NSNumber numberWithInt:0]
• [NSNumber numberWithDouble:1.0]

55. Objective-C
•C
•
•
• C

56. Objective-C
• OOP
•

57. Objective-C
• OS
•
•
• /

58. •
• delegate
• target/action
• ARC(Automatic Reference Counting)
• Blocks
• Grand Central Dispatch