Objective-C for Java developers

A simple presentation for who's coming from a Java background and trying to get into Objective-C .

Transcript

1. Objective-c FOR JAVA DEVELOPERS
2. 1OBjective-c For Java developers The basics
3. 1Hello world System.out.println("Hello, World!"); NSLog(@"Hello, World!");
4. 1Basic types byte aByte = 0; short aShort = 0; int anInt = 0; long aLong = 0; float aFloat = 0; double aDouble = 0; boolean aBoolean = true; //false char aChar = 'a'; Object anObject = new Object(); char aByte = 0; short aShort = 0; int anInt = 0; long aLong = 0; float aFloat; double aDouble; BOOL aBoolean = YES; //NO char aChar = 'a'; NSObject *anObject = [[NSObject alloc] init];
5. 1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];
6. 1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];
7. 1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];
8. 1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];
9. 1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];
10. the basics are the same! Recap
11. the basics are the same! also, YAY for unsigned Recap
12. 2OBjective-c For Java developers Meet the objects
13. 2Pointers String s = new String(); NSString *s = [[NSString alloc] init];
14. 2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE
15. 2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE
16. 2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE
17. 2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE Object *
18. 2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE
19. 2NSWhat? "Many of those strange primitive wrapper classes, like Integer and Number came from Lee Boynton, one of the early NeXT Obj-C class library guys who hated 'int' and 'float' types." Patrick Naughton (one of the original creators of Java)
20. 2String String aString = new String("A string."); NSString *aString = [[NSString alloc] initWithString:@"A string."];
21. 2String String aString = new String("A string."); NSString *aString = [[NSString alloc] initWithString:@"A string."];
22. 2String String aString = new String("A string."); NSString *aString = [[NSString alloc] initWithString:@"A string."]; String aString = "A string."; NSString *aString = @"A string.";
23. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three];
24. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three];
25. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three];
26. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three];
27. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three];
28. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three];
29. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three]; But... If I can use C++ then I can use operator overloading to add that to Objective-C, right?
30. 2“A” + “B” String one = "1 + "; int two = 2; String equals = " = "; float three = 3.0f; String s = one + two + equals + three; NSString *one = @"1 +"; int two = 2; NSString *eq = @"="; float three = 3.0; NSString *s = [NSString stringWithFormat:@"%@ %d %@ %.1f", one, two, eq, three]; But... If I can use C++ then I can use operator overloading to add that to Objective-C, right? Nop :(
31. 2(NS)Array String strings[] = {"1", "2"}; NSArray *strings = @[@"1", @"2"];
32. 2(NS)Array String strings[] = new String[10]; NSString **strings = malloc(10*sizeof(NSString *));
33. List<String> strings = new ArrayList<String>(10); NSMutableArray *strings = [NSMutableArray arrayWithCapacity:10]; 2(NS)Array
34. 2Dictionary Map<Object, Object> m = new HashMap<Object,Object>(); m.put("key","value"); NSDictionary *m = @{@"key" : @"value"};
35. 2Dictionary Map<Object, Object> m = new HashMap<Object,Object>(); m.put("key","value"); NSMutableDictionary *m = [@{@"key" : @"value"} mutableCopy]; [m setObject:@"key2" forKey:@"value2"];
36. 2Dictionary Map<Object, Object> m = new HashMap<Object,Object>(); m.put("key","value"); NSMutableDictionary *m = [@{@"key" : @"value"} mutableCopy]; [m setObject:@"key2" forKey:@"value2"];
37. 2Dictionary Map<Object, Object> m = new HashMap<Object,Object>(); m.put("key","value"); NSMutableDictionary *m = [@{@"key" : @"value"} mutableCopy]; [m setObject:@"key2" forKey:@"value2"];
38. 2Literals String s = "value1"; Number n = 3.14159265359; String a[] = {"value1","value2"}; Map<String,String> m = new HashMap<String,String>(); m.put("key","value"); Number arr[] = { Math.round(2*Math.PI) }; NSString *s = @"value1"; NSNumber *n = @3.14159265359; NSArray *a = @[@"value1", @"value2"]; NSDictionary *m = @{@"key" : @"value"}; NSArray *arr = @[ @(roundf(2*M_PI)) ]; NSMutableDictionary *dict = [NSMutableDictionary dictionary]; dict[@"key1"] = @"value1";
39. Recap POINTER = OBJECT LITERALS ARE AWESOME INIT INITIALIZE ALLOC CREATE
40. Recap POINTER = OBJECT STRING CONCAT SUCKS LITERALS ARE AWESOME INIT INITIALIZE ALLOC CREATE
41. 3OBjective-c For Java developers Interfaces & implementations
42. 3.h & .m @interface Foo : NSObject { //protected/private/public ivars } //Property declarations //Method declarations @end @implementation Foo { //Private ivars } //Synthesize properties //Method implementations //Private methods @end .h .m
43. 3Foo class @interface Foo : NSObject - (id)initWithBar:(NSString *)bar; @end @implementation Foo { NSString *_bar; } - (id)initWithBar:(NSString *)bar { self = [super init]; if (self != nil) { _bar = [bar copy]; } return self; } @end .h .m
44. 3 nil? Don’t you mean null? Foo class @interface Foo : NSObject - (id)initWithBar:(NSString *)bar; @end @implementation Foo { NSString *_bar; } - (id)initWithBar:(NSString *)bar { self = [super init]; if (self != nil) { _bar = [bar copy]; } return self; } @end .h .m
45. 3 nil? Don’t you mean null? Nop Foo class @interface Foo : NSObject - (id)initWithBar:(NSString *)bar; @end @implementation Foo { NSString *_bar; } - (id)initWithBar:(NSString *)bar { self = [super init]; if (self != nil) { _bar = [bar copy]; } return self; } @end .h .m
46. 3 nil? Don’t you mean null? Nop Foo class self? Don’t you mean this? @interface Foo : NSObject - (id)initWithBar:(NSString *)bar; @end @implementation Foo { NSString *_bar; } - (id)initWithBar:(NSString *)bar { self = [super init]; if (self != nil) { _bar = [bar copy]; } return self; } @end .h .m
47. 3 nil? Don’t you mean null? Nop Foo class self? Don’t you mean this? Nop @interface Foo : NSObject - (id)initWithBar:(NSString *)bar; @end @implementation Foo { NSString *_bar; } - (id)initWithBar:(NSString *)bar { self = [super init]; if (self != nil) { _bar = [bar copy]; } return self; } @end .h .m
48. 3Foo class @interface Foo : NSObject - (id)initWithBar:(NSString *)bar; @end @implementation Foo { NSString *_bar; } - (id)initWithBar:(NSString *)bar { self = [super init]; if (self != nil) { _bar = [bar copy]; } return self; } @end .h .m
49. 3+ & - @interface Foo : NSObject - (int)sumA:(int)a withB:(int)b; + (Foo *)aFoo; @end @implementation Foo - (int)sumA:(int)a withB:(int)b { return a+b; } + (Foo *)aFoo { return [[Foo alloc] init]; } @end .h .m
50. 3Properties @interface Foo : NSObject @property (nonatomic, copy) NSString *bar; @end .h @implementation Foo @synthesize bar; @end .m class Foo { private String bar; public String getBar() { return bar; } public void setBar(String bar) { this.bar = bar; } }
51. 3NSWhat? "I'm pretty sure that Java's 'interface' is a direct rip-off of Obj-C's 'protocol' which was largely designed by these ex-NeXT'ers..." Patrick Naughton (one of the original creators of Java)
52. 3Protocols interface Color { public int getRed(); public int getBlue(); public int getGreen(); } @protocol Color <NSObject> - (int)red; - (int)green; - (int)blue; @opcional - (int)rgb; @end
53. 3Categories @interface NSString (MD5) - (NSString *)md5Hash; @end @implementation NSString (MD5) - (NSString *)md5Hash { NSString *md5 = anMD5Func(self); return md5; } @end .h .m
54. Recap PROPERTIES ARE AWESOME IMPLEMENTATION .M Interface .H Interfaces are called protocols and there’s no abstract classes
55. Recap PROPERTIES ARE AWESOME IMPLEMENTATION .M Interface .H Interfaces are called protocols and there’s no abstract classes And imagine what you can do with categories
56. 4OBjective-c For Java developers remember c?
57. 4NOOO! @implementation Foo - (int)anAddress { char *bar = malloc(1); free(bar); return &bar; } @end int main(int argc, char *argv[]) { @autoreleasepool { Foo *foo = [[Foo alloc] init]; printf("0x%X",[foo anAddress]); } } Foo.m main.m
58. 4Why C? "Objective-C is a hybrid programming language[…]formed by grafting the Smalltalk-80 style of object-oriented programming onto a C language rootstock. Objective-C adds precisely one new data type, the object[...]and precisely one new operation, the message expression. " Cox, Brad J. (1991). Object Oriented Programming: An Evolutionary Approach
59. 4The Object typedef struct objc_object { Class isa; } *id; typedef struct objc_class *Class; objc.h struct objc_class { Class isa; }; runtime.h
60. 4CF Core Foundation is a library with a set of programming interfaces conceptually derived from the Objective-C-based Foundation framework but implemented in the C language. To do this, Core Foundation implements a limited object model in C. Core Foundation defines opaque types that encapsulate data and functions, hereafter referred to as “objects.”
61. Recap C Is at the bottom of objective-c and YOU SHOULD TAKE ADVANTAGE OF IT
62. Recap C Is at the bottom of objective-c and YOU SHOULD TAKE ADVANTAGE OF IT BUT C DOES NOT HAVE ARC SO YOU ARE STUCK WITH MALLOC AND FREE
63. 5OBjective-c For Java developers BLOCKS
64. 5Closures //create the array NSArray *arr = @[ @16, @11, @88 ]; //sort it using a block NSArray *sortedArr = [arr sortedArrayUsingComparator:^(id obj1, id obj2) { return [((NSNumber *)obj1) compare:(NSNumber *)obj2]; }]; //print NSLog(@"%@",sortedArr);
65. 5Keep it //save a block in a variable int (^aBlock)(int, int) = ^(int i, int j) { return i * j; }; //execute it int result = aBlock(1,2);
66. 5Get it //get the block as a parameter - (int)operationWithArg1:(int)i arg2:(int)j block:(int (^)(int, int))aBlock { return aBlock(i,j); }
67. 5Blocks & Memory “If you are using ARC, object variables are retained and released automatically as the block is copied and later released.” “If you use a block within the implementation of a method [...] If you access an instance variable by reference, self is retained; If you access an instance variable by value, the variable is retained.” “When you copy a stack-based block, you get a new block. If you copy a heap-based block, however, you simply increment the retain count of that block and get it back as the returned value of the copy function or method.”
68. Recap BLOCKS Is MY FAVORITE OBJECTIVE-C LIBRARY AND IT WILL BE ONE OF YOURS TOO
69. Recap BLOCKS Is MY FAVORITE OBJECTIVE-C LIBRARY AND IT WILL BE ONE OF YOURS TOO The notation is hard to MASTER though
70. 6OBjective-c For Java developers Other stuff
71. 6Ϋʔϧʂ NSString *localizedAbout = NSLocalizedString(@"About", nil); ... "About" = "Sobre"; "Open" = "Abrir"; "Close" = "Fechar"; ... Localizable.strings
72. 6Read it - (void)insertSublayer:(CALayer *)layer below:(CALayer *)sibling; - (void)insertSublayer:(CALayer *)layer above:(CALayer *)sibling; - (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx; - (id)initWithRequest:(NSURLRequest *)request delegate:(id)delegate startImmediately: (BOOL)startImmediately NS_AVAILABLE(10_5, 2_0);
73. Recap this is just the beginning. There’s a lot more to objective-c
74. Recap this is just the beginning. There’s a lot more to objective-c But now it won’t scare you !
75. 7OBjective-c For Java developers DEMO
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