From 7496526cf447c6f5459a9b32448d2ba6e0f60dc0 Mon Sep 17 00:00:00 2001 From: Levi Bostian Date: Mon, 6 Jan 2014 20:18:45 -0600 Subject: [PATCH] Add more examples of methods available to objects. --- objective-c.html.markdown | 51 ++++++++++++++++++++++++++++++++------- 1 file changed, 42 insertions(+), 9 deletions(-) diff --git a/objective-c.html.markdown b/objective-c.html.markdown index e1834bf8..cdf89338 100644 --- a/objective-c.html.markdown +++ b/objective-c.html.markdown @@ -297,9 +297,10 @@ int main (int argc, const char * argv[]) } // Convenient notation for public access variables to auto generate a setter method. // By default, setter method name is 'set' followed by @property variable name. -@property int count; // Setter method name = 'setCount' -@property (copy) NSString *name; // (copy) => Copy the object during assignment. -@property (readonly) id data; // (readonly) => Cannot set value outside interface. +@property int propInt; // Setter method name = 'setCount' +@property (copy) id copyId; // (copy) => Copy the object during assignment. +// (readonly) => Cannot set value outside interface. +@property (readonly) NSString *roString; // Use @synthesize in @implementation to create accessor. // You can customize the getter and setter names instead of using default 'set' name: @property (getter=lengthGet, setter=lengthSet:) int length; @@ -308,12 +309,15 @@ int main (int argc, const char * argv[]) // + for class method. + (NSString *)classMethod; -+ (MyClass *)myClassFromName:(NSString *)name; ++ (MyClass *)myClassFromHeight:(NSNumber *)defaultHeight; // - for instance methods. - (NSString *)instanceMethodWithParameter:(NSString *)string; - (NSNumber *)methodAParameterAsString:(NSString*)string andAParameterAsNumber:(NSNumber *)number; +// Constructor methods with arguments: +- (id)initWithDistance:(int)defaultDistance; + @end // States the end of the interface. @@ -341,6 +345,7 @@ NSString *stringFromInstanceMethod = [myClass instanceMethodWithParameter:@"Hell // Implement the methods in an implementation (MyClass.m) file: @implementation MyClass { long distance; // Private access instance variable. + NSNumber height; } // To access a public variable from the interface file, use '_' followed by variable name: @@ -348,27 +353,49 @@ _count = 5; // References "int count" from MyClass interface. // Access variables defined in implementation file: distance = 18; // References "long distance" from MyClass implementation. -// Call when the object is releasing -- (void)dealloc +// Called before calling any class methods or instantiating any objects. ++ (void)initialize { + if (self == [MyClass class]) { + distance = 0; + } } -// Constructors are a way of creating classes +// Counterpart to initialize method. Called when an object's reference count is zero. +- (void)dealloc +{ + [height release]; // If not using ARC, make sure to release class variable objects + [super dealloc]; // and call parent class dealloc. +} + +// Constructors are a way of creating instances of classes. // This is a default constructor which is called when the object is initialized. - (id)init { - if ((self = [super init])) + if ((self = [super init])) // 'super' used to access methods from parent class. { - self.count = 1; + self.count = 1; // 'self' used for object to send messages to itself. } return self; } +// Can create constructors that contain arguments: +- (id)initWithDistance:(int)defaultDistance +{ + distance = defaultDistance; + return self; +} + (NSString *)classMethod { return [[self alloc] init]; } ++ (MyClass *)myClassFromHeight:(NSNumber *)defaultHeight +{ + height = defaultHeight; + return [[self alloc] init]; +} + - (NSString *)instanceMethodWithParameter:(NSString *)string { return @"New string"; @@ -379,6 +406,12 @@ distance = 18; // References "long distance" from MyClass implementation. return @42; } +// If you create a method in @implementation but do not include in @interface, it is private. +- (NSNumber *)secretPrivateMethod { + return @72; +} +[self secretPrivateMethod]; // Calls private method. + // Methods declared into MyProtocol - (void)myProtocolMethod {