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authorLevi Bostian <levi.bostian@gmail.com>2014-01-06 20:18:45 -0600
committerLevi Bostian <levi.bostian@gmail.com>2014-01-08 12:45:40 -0600
commit7496526cf447c6f5459a9b32448d2ba6e0f60dc0 (patch)
treeba048408d80bda40bfef2bc8726bab52027232c8 /objective-c.html.markdown
parent5ad738af38b4642257f5036ac5ed7dbc27f4e187 (diff)
Add more examples of methods available to objects.
Diffstat (limited to 'objective-c.html.markdown')
-rw-r--r--objective-c.html.markdown49
1 files changed, 41 insertions, 8 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
+// Called before calling any class methods or instantiating any objects.
++ (void)initialize
+{
+ if (self == [MyClass class]) {
+ distance = 0;
+ }
+}
+
+// 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 classes
+// 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
{