ObjC.pdf

TheObjective-CProgrammingLanguage

Tools&Languages:Objective-C

2010-12-08

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Contents

Introduction Introduction 9

WhoShouldReadThisDocument 9

OrganizationofThisDocument 9

Conventions 10

SeeAlso 11

TheRuntimeSystem 11

MemoryManagement 11

Chapter1 Objects,Classes,andMessaging 13

TheRuntimeSystem 13

Objects 13

ObjectBasics 13

id 14

DynamicTyping 14

MemoryManagement 15

ObjectMessaging 15

MessageSyntax 15

SendingMessagestonil 17

TheReceiver’sInstanceVariables 18

Polymorphism 18

DynamicBinding 19

DynamicMethodResolution 19

DotSyntax 19

Classes 23

Inheritance 23

ClassTypes 26

ClassObjects 28

ClassNamesinSourceCode 32

TestingClassEquality 33

Chapter2 DefiningaClass 35

SourceFiles 35

ClassInterface 35

ImportingtheInterface 37

ReferringtoOtherClasses 37

TheRoleoftheInterface 38

ClassImplementation 38

ReferringtoInstanceVariables 39

TheScopeofInstanceVariables 40

CONTENTS

Messagestoselfandsuper 43

AnExample:Usingselfandsuper 44

Usingsuper 45

Redefiningself 46

Chapter3 AllocatingandInitializingObjects 49

AllocatingandInitializingObjects 49

TheReturnedObject 49

ImplementinganInitializer 50

ConstraintsandConventions 50

HandlingInitializationFailure 52

CoordinatingClasses 53

TheDesignatedInitializer 55

CombiningAllocationandInitialization 57

Chapter4 Protocols 59

DeclaringInterfacesforOtherstoImplement 59

MethodsforOtherstoImplement 60

DeclaringInterfacesforAnonymousObjects 61

NonhierarchicalSimilarities 61

FormalProtocols 62

DeclaringaProtocol 62

OptionalProtocolMethods 62

InformalProtocols 63

ProtocolObjects 64

AdoptingaProtocol 64

ConformingtoaProtocol 65

TypeChecking 65

ProtocolsWithinProtocols 66

ReferringtoOtherProtocols 67

Chapter5 DeclaredProperties 69

Overview 69

PropertyDeclarationandImplementation 69

PropertyDeclaration 70

PropertyDeclarationAttributes 70

PropertyImplementationDirectives 73

UsingProperties 74

SupportedTypes 74

PropertyRedeclaration 75

Copy 75

dealloc 76

CoreFoundation 77

CONTENTS

Example:DeclaringPropertiesandSynthesizingAccessors 77

SubclassingwithProperties 79

PerformanceandThreading 79

RuntimeDifference 80

Chapter6 CategoriesandExtensions 81

AddingMethodstoClasses 81

HowYouCanUseCategories 82

CategoriesoftheRootClass 83

Extensions 83

Chapter7 AssociativeReferences 87

AddingStorageOutsideaClassDefinition 87

CreatingAssociations 87

RetrievingAssociatedObjects 88

BreakingAssociations 88

CompleteExample 88

Chapter8 FastEnumeration 91

Thefor…inSyntax 91

AdoptingFastEnumeration 91

UsingFastEnumeration 92

Chapter9 EnablingStaticBehavior 95

DefaultDynamicBehavior 95

StaticTyping 95

TypeChecking 96

ReturnandParameterTypes 97

StaticTypingtoanInheritedClass 97

Chapter10 Selectors 99

MethodsandSelectors 99

SELand@selector 99

MethodsandSelectors 100

MethodReturnandParameterTypes 100

VaryingtheMessageatRuntime 100

TheTarget-ActionDesignPattern 101

AvoidingMessagingErrors 101

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