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Objective-c FOR JAVA DEVELOPERS

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1OBjective-c For Java developers The basics

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1Hello world System.out.println("Hello, World!"); NSLog(@"Hello, World!");

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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];

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1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];

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1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];

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1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];

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1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];

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1Methods String aString = new String(chars); NSString *aString = [[NSString alloc] initWithUTF8String:chars];

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the basics are the same! Recap

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the basics are the same! also, YAY for unsigned Recap

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2OBjective-c For Java developers Meet the objects

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2Pointers String s = new String(); NSString *s = [[NSString alloc] init];

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2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE

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2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE

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2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE

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2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE Object *

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2Pointers String s = new String(); NSString *s = [[NSString alloc] init]; Stuff 0x3DE2FE

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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)

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2String String aString = new String("A string."); NSString *aString = [[NSString alloc] initWithString:@"A string."];

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2String String aString = new String("A string."); NSString *aString = [[NSString alloc] initWithString:@"A string."];

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2String String aString = new String("A string."); NSString *aString = [[NSString alloc] initWithString:@"A string."]; String aString = "A string."; NSString *aString = @"A string.";

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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];

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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];

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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];

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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];

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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];

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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];

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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?

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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 :(

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2(NS)Array String strings[] = {"1", "2"}; NSArray *strings = @[@"1", @"2"];

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2(NS)Array String strings[] = new String[10]; NSString **strings = malloc(10*sizeof(NSString *));

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List strings = new ArrayList(10); NSMutableArray *strings = [NSMutableArray arrayWithCapacity:10]; 2(NS)Array

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2Dictionary Map m = new HashMap(); m.put("key","value"); NSDictionary *m = @{@"key" : @"value"};

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2Dictionary Map m = new HashMap(); m.put("key","value"); NSMutableDictionary *m = [@{@"key" : @"value"} mutableCopy]; [m setObject:@"key2" forKey:@"value2"];

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2Dictionary Map m = new HashMap(); m.put("key","value"); NSMutableDictionary *m = [@{@"key" : @"value"} mutableCopy]; [m setObject:@"key2" forKey:@"value2"];

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2Dictionary Map m = new HashMap(); m.put("key","value"); NSMutableDictionary *m = [@{@"key" : @"value"} mutableCopy]; [m setObject:@"key2" forKey:@"value2"];

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2Literals String s = "value1"; Number n = 3.14159265359; String a[] = {"value1","value2"}; Map m = new HashMap(); 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";

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Recap POINTER = OBJECT LITERALS ARE AWESOME INIT INITIALIZE ALLOC CREATE

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Recap POINTER = OBJECT STRING CONCAT SUCKS LITERALS ARE AWESOME INIT INITIALIZE ALLOC CREATE

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3OBjective-c For Java developers Interfaces & implementations

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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

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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

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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

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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

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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

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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

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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

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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

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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; } }

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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)

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3Protocols interface Color { public int getRed(); public int getBlue(); public int getGreen(); } @protocol Color - (int)red; - (int)green; - (int)blue; @opcional - (int)rgb; @end

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3Categories @interface NSString (MD5) - (NSString *)md5Hash; @end @implementation NSString (MD5) - (NSString *)md5Hash { NSString *md5 = anMD5Func(self); return md5; } @end .h .m

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Recap PROPERTIES ARE AWESOME IMPLEMENTATION .M Interface .H Interfaces are called protocols and there’s no abstract classes

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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

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4OBjective-c For Java developers remember c?

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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

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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

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4The Object typedef struct objc_object { Class isa; } *id; typedef struct objc_class *Class; objc.h struct objc_class { Class isa; }; runtime.h

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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.”

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Recap C Is at the bottom of objective-c and YOU SHOULD TAKE ADVANTAGE OF IT

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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

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5OBjective-c For Java developers BLOCKS

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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);

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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);

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5Get it //get the block as a parameter - (int)operationWithArg1:(int)i arg2:(int)j block:(int (^)(int, int))aBlock { return aBlock(i,j); }

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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.”

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Recap BLOCKS Is MY FAVORITE OBJECTIVE-C LIBRARY AND IT WILL BE ONE OF YOURS TOO

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Recap BLOCKS Is MY FAVORITE OBJECTIVE-C LIBRARY AND IT WILL BE ONE OF YOURS TOO The notation is hard to MASTER though

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6OBjective-c For Java developers Other stuff

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6Ϋʔϧʂ NSString *localizedAbout = NSLocalizedString(@"About", nil); ... "About" = "Sobre"; "Open" = "Abrir"; "Close" = "Fechar"; ... Localizable.strings

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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);

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Recap this is just the beginning. There’s a lot more to objective-c

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Recap this is just the beginning. There’s a lot more to objective-c But now it won’t scare you !

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7OBjective-c For Java developers DEMO

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