ObjectiveC最新汉化版全集教程

1、PageObjective-C Beginner's Guide目录l 始吧0下载这篇教学°设定环境刖,° 编译 hello worldl 创立 Classes° interface° implementation0把它们凑在一路l详细说明0多重参数°建构子(Constructors )0存取权限° Class level access°异样情形(Exceptions )处置l继承、多型(Inheritance, Polymorphism )和其它对象导向功能° id型别继承(Inheritance)动态识

2、另1J( Dynamic types )° Categories° Posing° Protocolsl内存治理° Retain and Release (保存与释放)° Dealloc° Autorelease Pooll Foundation Framework Classes° NSArray° NSDictionaryl优势与缺点l更多信息开始吧Page 2Objective-C Beginner's Guide页码,2/43o设定环境n Linux/FreeBSD:安装 GNUStepn为了编译G

3、NUstep应用程序,必需先执行位于 /usr/GNUstep/System/Makefiles/ 的那个档案.那个途径取决于你的系统环境,有些是在/usr, some/usr/lib ,有些是/usr/local.假设是你的 shell是以csh/tcsh为根底的 shell,那么应该改用.建议把那个指令放在 .bashrc或.cshrc中.n Mac OS X:安装 XCoden Windows NT :安装 cygwin 或 mingw ,然后安装 GNUStepo 前言n这篇教学假设你已经有一些大体的C语言知识,包才C数据型别、什么是函式、什么是回传值、关于指针的知识和大体的C语言内存

4、治理.假设是您没有这些背景知识,我超级建议你读一读 K&R的书：The C ProgrammingLanguage 译注：台湾出版书名为C程序语言第 版这是C语言的设计者所写的.n Objective-C,是C的衍生语言,继承了所有 C语言的特性. 是有一些例外,可是它们不是继承于 C的语言特性本身.n nil ：在C/C+你或许曾利用过 NULL ,而在 Objective-C 中 那么是nil.不同之处是你能够传递讯息给nil例如nil message;,这是完全合法的,但是你却不能对NULL依样画葫芦.n BOOL ： C没有正式的布尔型别,而在 Objective-C 中也不

5、是真的有.它是包括在Foundation classes 大体类别库中即import ; nil也是包括在那个标头档内.BOOL在Objective-C中有两种 型态：YES或NO,而不是 TRUE 或 FALSE.n #import vs #include :就犹如你在 hello world 范例中看到的, 咱们利用了#import.#import 由gcc编译器支持.我并非建议利用#include, #import 大体上跟.h档头尾的#ifndef #define #endif 相同.许多程序员们 都同意,利用这些东西这是十分愚蠢的.不管如何,利用 #import就对了. 如此不但能够

6、避gccObjective-C免麻烦,而且万一有一天把它拿掉了,将会有足够的程序员能够坚持保存它或是将它放回来.偷偷告知你,Apple在它们官方的程序代码中也利用了 #import .因此万一有一天这种事真的发生,不难预料Apple将会提供一个支持#import的gcc分支版本.n在 Objective-C 中,method及message这两个字是能够互 换的.只是 messages拥有专门的特性,一个message能够动态的转送给另一个对象.在 Objective-C中,呼对象上的一个讯息并非必然表示对象真的会实作 那个讯息,而是对象明白如何以某种方式去实作它,或是转送给明白如何实作的对象

7、.o 编译 hello world nS#import <>SSint main( int argc, const char *argv口)Sprintf( "hello worldn");桌面 Objective-C Begi. 2021-2-6PDF created with pdfFactory Pro trial versionPage 3return 0;)n输出hello worldn 在 Objective-C 中利用 #import 代替 #includen Objective-C 的预设扩展名是.m创立 classeso interface20

8、04n 基于"Programming in Objective-C," Copyright by Sams Publishing 一 中的范例,并通过许诺而刊载.nS#importFoundation/Sinterface Fraction: NSObject Sint numerator;Sint denominator;S)SS-(void) print;S-(void) setNumerator: (int) d;S-(void) setDenominator: (int) d;S-(int) numerator;S-(int) denominator;Sendn N

9、SObject : NeXTStep Object的缩写.由于它已经更名 为OpenStep,因此这在今天已经不是那么成心义了.n继承(inheritance )以Class: Parent表示,就像上面的 Fraction: NSObject.n 夹在 interface Class: Parent . 中的称为 instance variables.n没有设定存取权限(protected, public, private )时,预 设的存取权限为protected o设定权限的方式将在稍后说明.n Instance methods 跟在成员变数 (即 instance variables)

10、后.格式为：scope(returnType)methodName:(parameter1Type)parameterIName;instancen scope 有 class 或 instance 两种. methods 以- 头,class levelmethods 以 + 头.n Interface以一个end作为终止.o implementation2004n 基于"Programming in Objective-C," Copyright by Sams Publishing 一 中Begi.and桌 面 Objective-C2021-2-6PDF creat

11、ed with pdfFactory Pro trial versionPage 4GuideObjective-CBeginner's页码,4/43的范例,并通过许诺而刊载.nS#import ""S#import <>SSS denominator );SSSSSSSSSSSSSSSSS©implementation Fraction-(void) print printf( "%i/%i", numerator,)- (void) setNumerator: (int) n numerator = n;)- (void

12、) setDenominator: (int) d denominator = d;)- (int) denominator return denominator;)- (int) numerator return numerator;)endn Implementation ©implementation ClassName 开 始,以end终止.n Implement概念好的 methods的方式,跟在interface 中宣告时很近似.o把它们凑在一路n基于 "Programming in Objective-C," Copyright 2004 by Sa

13、ms Publishing 一 中的范例,并通过许诺而刊载.nS#import <>S#import ""SSint main( int argc, const char *argv)(S.2021-2-6PDF created with pdfFactory Pro trial versionPage 5Objective-CBeginner'sGuide页码,5/43frac print;Sprintf( "n");SS.o多重参数n目前为止我还没展现如何传递多个参数.那个语法乍看之下不是很直觉,不过它却是来自一个十分受欢送的Sm

14、alltalk版本.n 基于"Programming in Objective-C," Copyright 2004 by Sams Publishing 一 中的范例,并通过许诺而刊载.nS.S-(void) setNumerator: (int) nandDenominator: (int) d;S-(void) setNumerator: (int) nandDenominator: (int) d 桌面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPage 6Object

15、ive-CBeginner'sGuide页码,6/43Snumerator = n;Sdenominator = d;SnS#import <>S#import ""SS.2021-2-6PDF created with pdfFactory Pro trial versionPage 7Objective-CBeginner'sGuide页码,7/43 略label名称,但以：区隔参数.并非建议如此利 用.o 建构子(Constructors )n基于"Programming in Objective-C," Copyrig

16、ht 2004 by Sams Publishing 一 中的范例,并通过许诺而刊载. n S.S-(Fraction*) initWithNumerator: (int)n denominator: (int) d;SS n denominator: (int) d SSSS andDenominator: d;SSSS-(Fraction*) initWithNumerator: (int) self = super init;if ( self ) self setNumerator: nreturn self;nSSS#import <>#import "&quo

17、t;2021-2-6PDF created with pdfFactory Pro trial versionPage 8Objective-C页码,8/43SSSSSSSSPDF created with pdfFactory Pro trial versionBeginner'sGuidefrac2 print;printf( "n");printf( "Fraction 3 is:");frac3 print;printf( "n");2021-2-6Page 9Objective-CBeginner'sGuid

18、e页码,9/43Sprivateint privateVar;int privateVar2;protectedint protectedVar;)#import ""©implementation Access#import ""#import <>int main( int argc, const char *argv)Access *a = Access alloc init;SSSSendnSSSendnSSSS(SS2021-2-6PDF created with pdfFactory Pro trial versionG

19、uidePageObjective-CBeginner's页码,10/43SSstatic int count;SSinterface ClassA: NSObjectS+(int) initCount;S+(void) initialize;endnS#import ""SSimplementation ClassAend-(id) init self = super init;count+;return self;+(int) initCount return count;+(void) initialize count = 0;#import "&q

20、uot;#import <>ClassA *c1 = ClassA allocinit;SClassA *c2 = ClassA allocinit;SS.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,11/43n outputSClassA count: 2ClassA count: 3n static int count = 0; 这是 class variable 宣告的方式. 其 实这种变量摆在那个地址并不睬想,比拟好的解法是像Java实作s

21、tatic classvariables的方式.但是,它确实能用.n +(int) initCount; 这是回传count值的实际 method.请注 意这细的不同！这里在type前面不用减号-而改用加号 +.加号+表示 这是一个 class levelfunction o (译注： 许多文件中,class level functions 被称为 class functions 或class method)n存取那个变数跟存取一样成员变数没有两样,就像 ClassA 中的 count+ 用法.n +(void) initialize method is 在 Objective-C 开始执行你

22、 的程序时被呼,而且它也被每一个 class呼.这是初始化像咱们的count这种 class level variables 的好地址.o 异样情形(Exceptions)n注意：异样处置只有Mac OS X以上才支持.n 基于"Programming in Objective-C," Copyright 2004 by Sams Publishing 一 中的范例,并通过许诺而刊载.n#import <Foundation/>Sinterface CupWarningException:NSExceptionend n S#import "SS

23、69;implementation CupWarningExceptionend n S#import <Foundation/>SS©interface CupOverflowException:NSExceptionend桌面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,12/43S#import ""SSimplementationCupOverflowExceptionendn

24、S#importFoundation/SSinterface Cup: NSObject Sint level;S)S-(int) level;S-(void)setLevel:(int)l;S-(void)fill;S-(void)empty;S-(void)print;endnS#import ""S#import ""S#import ""S#importFoundation/S#importFoundation/SS©implementation CupS-(id) init Sself = super init;S

25、if ( self ) self setLevel: 0;S)SSreturn self;S)SS-(int) level Sreturn level;S)SS-(void) setLevel: (int) l Slevel = l;SSif ( level > 100 ) S.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,13/43Sis above 100"reason: "The leveluserinfo: nil;Sthrow

26、 e;S else if ( level >= 50 ) S.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,14/43Scup fill;Scup print;SSS. n还有一个finally区块,它的行为就像Java的异样处 置方式,finally区块的内容保证会被呼.and桌 面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CB

27、eginner'sGuide页码,15/43n 里的 "CupOverflowException"是一个 NSString 常 数物件.在Objective-C中,符号通经常使用来代表这是语言 的衍生部份.C语言形式的字符串(C string )就像 C/C+ 一样是"String constant" 的形式,型别为char *.继承、多型(Inheritance, Polymorphism )以及其它对象导向功能o id型别n Objective-C有种叫做id的型别,它的运作有时候像 是void* ,只是它却严格规定只能用在对象.Object

28、ive-C与Java跟C+不一样,你在呼一个对象的method时,并非需要明白那个对象的型别.固然 那个method必然要存在,这称为 Objective-C的讯息传递.n 基于"Programming in Objective-C," Copyright 2004 by Sams Publishing 一 中的范例,并通过许诺而刊载.SSSSSSSS denominator: (int) d;SSSS andDenominator: (int) d;SSendnS#import <Foundation/>interface Fraction: NSObject

29、 int numerator;int denominator;-(Fraction*) initWithNumerator: (int) n- (void) print;- (void) setNumerator: (int) d;- (void) setDenominator: (int) d;-(void) setNumerator: (int) n-(int) numerator;-(int) denominator;#import ""S#import <>SS©implementation FractionS-(Fraction*) init

30、WithNumerator: (int) ndenominator: (int) d Sself = super init;SSif ( self ) Sself setNumerator: nandDenominator: d;S)SSreturn self;S)and桌 面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,16/43-(void) print S denominator );SSSSSSSSSSS andDen

31、ominator: (int) d SSSSSSSSSprintf( "%i / %i", numerator,)-(void) setNumerator: (int) n numerator = n;)-(void) setDenominator: (int) d denominator = d;)-(void) setNumerator: (int) nnumerator = n;denominator = d;)-(int) denominator return denominator;)-(int) numerator Sreturn numerator;S)end

32、 nSSSSSSSS r andlmaginary: (double) i;SSS andlmaginary: (double) i;SSS#import <Foundation/>interface Complex: NSObject double real;double imaginary;)-(Complex*) initWithReal: (double)-(void) setReal: (double) r;-(void) setImaginary: (double) i;-(void) setReal: (double) r- (double) real;- (doub

33、le) imaginary;- (void) print;endnS#import "S#import <>and桌 面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,17/43 S S©implementation ComplexS-(Complex*) initWithReal: (double)r andlmaginary: (double) i Sself = super init;if

34、( self ) self setReal: randlmaginary: i;SSSSSSSSSSSSSSandlmaginary: (double) i SSSSSSreturn self;-(void) setReal: (double) r real = r;-(void) setImaginary: (double) i imaginary = i;-(void) setReal: (double) rreal = r;imaginary = i;-(double) real return real;S)SS-(double) imaginary Sreturn imaginary;

35、S)SS-(void) print Sprintf( "%_f + %_fi", real,imaginary );S)S end nS#import<>S#import""S#import""SSint main( int argc, const char*argv口)2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,18/43SSntValue()就得先转型,然后才能呼那个method. o

36、 继承(Inheritance) n基于 "Programming in Objective-C," Copyright 2004 by Sams Publishing 一 中 的范例,并通过许诺而刊载. nS#importFoundation/S Sinterface Rectangle: NSObject Sint width;Sint height;S-(Rectangle*) initWithWidth: (int) wheight: (int) h;S-(void) setWidth:(int) w;S-(void) setHeight:(int)h;S-(voi

37、d) setWidth: (int) w height: (int) h;S-(int) width;S-(int) height;and桌 面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPageObjective-CBeginner'sGuide页码,19/43S-(void) print;endn#import ""SSSS w height: (int) h SSSS height: h;SSSSSSSSSSSS#import <>©impl

38、ementation Rectangle-(Rectangle*) initWithWidth: (int) self = super init;if ( self ) self setWidth: w)return self;)-(void) setWidth: (int) w width = w;)-(void) setHeight: (int) h height = h;)S h (SSSSSSSSSSSSSS =%i", width, height );S- (void) setWidth: (int) w height: (int)width = w;height = h;

39、)- (int) width return width;)- (int) height return height;)- (void) print printf( "width = %i, height)endS#import "SSinterface Square: Rectangleand桌 面 Objective-C Begi.2021-2-6PDF created with pdfFactory Pro trial versionPage 20Objective-CBeginner'sGuide页码,20/43S-(Square*) initWithSize

40、: (int)s;S-(void) setSize: (int) s;S-(int) size;endnS#import "SS©implementation SquareS-(Square*) initWithSize: (int) s SSSSSSSSSSSSSSSSSSSSSself = super init;if ( self ) self setSize: s;)return self;)- (void) setSize: (int) s width = s;height = s;)- (int) size return width;)- (void) setWi

41、dth: (int) w self setSize: w;)S-(void) setHeight: (int) h Sself setSize: h;Send nS#import""S#import""S#import<>SSint main( int argc, const char*argv ) SSSquare *sq = Square allocinitWithSize: 15;SS.2021-2-6PDF created with pdfFactory Pro trial versionPage 2Objective-CBeginn

42、er'sGuide页码,21/43Srec print;Sprintf( "n");SSprintf("Square:");Ssq print;Sprintf("n");SS.2021-2-6PDF created with pdfFactory Pro trial versionPage 22GuideObjective-CBeginner's页码,22/43classObjclassObj-(BOOL) isMemberOfClass:此对象是不是是classObj的员does the object have a

43、method named specifiecby the selector此对象是不是有叫做selector 的 methoddoes an object createdby this class have theability to respond to theselector specified selector此对象是不是是由有能力响应指定 selector的对象所产生invoke the specifiedselector on the object唤起此对象的指定selector-(BOOL) respondsToSelector: selector+(BOOL) instances

44、RespondToSelector:-(id) performSelector: selectorn所有继承自NSObject都有一个可回传一个class物件的class method.这超级近似于 Java 的 getClass() method .那个 class 对象 被利用于前述的 methods中.n Selectors在Objective-C 用以表示讯息.下一个范例 会秀出成立selector的语法.n基于 "Programming in Objective-C," Copyright 2004 by Sams Publishing 一 中的范例,并通过许诺而

45、刊载.nS#import ""S#import ""S#import <>SSint main( int argc, const char *argv ) SSSquare *sq = Square allocinitWithSize: 15;S2021-2-6PDF created with pdfFactory Pro trial versionPage 23Objective-CBeginner'sGuide页码,23/43Sif ( sq isMemberOfClass:NSObject class = YES ) Sprin

46、tf( "square is amember of object classn");SSS2021-2-6PDF created with pdfFactory Pro trial versionPage 24Objective-CBeginner'sGuide页码,24/43S.2021-2-6PDF created with pdfFactory Pro trial versionPage 25Objective-CBeginner'sGuide页码,25/43SS)SS-(Fraction*) div: (Fraction*) f SSS)SS-(Fraction*) sub: (Fraction*) f SSSS)endnS#import <>S#import ""#import ""SSint main( int argc, const char*argv ) Sand桌 面 Objective-C Begi.2021-2-6