《Objective-C 基础教程》笔记
1. Hello
2. Extensions to C
#import
NSLog
%@
@"string"
BOOL YES NO
3. OOP
self
/* class.h BEGIN */
@interface Class:NSObject
{
int _member;
}
- (int)function:(int)parameter;
- (void)many_parameters_function:(int)parameter1 some_information:(NString *)parameter2;
- (void)no_parameter_function;
@end //Class
/* class.h END */
/* class.m BEGIN */
@implementation Class
- (int)function:(int)p
{
}//function
- (void)many_parameters_function:(int)p1 some_information:(NString *)p2
{
}//many_parameters_function
- (void)no_parameter_function
{
} //noparameter_function
@end //Class
/* class.m END */
Objective-C does not support multiple inheritance
/* Children.h BEGIN */ @interface Children : Parent @end //Children /* Children.h END */
super
isa()
overridden
5. Composition
description
6. Organization
@class sets up a forward reference
7. More About Xcode
defaults write com.apple.Xcode PBXCustomTemplateMacroDefinitions
'{"ORGANIZATIONNAME" = "zuohaitao";}'
command+shift+E
File->Make Snapshot
File->Snapshots
command+D
Help->Show Research Assistant.
8. Foundation Kit
NSRange
typedef struct _NSRange NSRange;
struct _NSRange
{
NSUInteger location;
NSUInteger length;
};
NSPoint
typedef struct _NSPoint NSPoint;
struct _NSPoint
{
CGFloat x;
CGFloat y;
};
NSSize
typedef struct _NSSize NSSize;
struct _NSSize
{
CGFloat width;
CGFloat height;
};
NSRect
typedef struct _NSRect NSRect;
struct _NSRect
{
NSPoint origin;
NSSize size;
};
NSString
+ (id)stringWithFormat:(NSString *)format,...
- (unsigned int)length
- (BOOL)isEqualToString:(NSString *)aString
- (NSComparisonResult)compare:(NSString *) string;
- (NSComparisonResult)compare:(NSString *) string
options:(unsigned) mask;
- (BOOL)hasPrefix:(NSString *)aString;
- (BOOL)hasSuffix:(NSString *)aString;
- (NSRange)rangeOfString:(NSString *) aString;
- (NSArray *)componentsSeparatedByString:(NSString *)separator
- (NSString *)componentsJoinedByString:(NSString *)separator
- (NSString *)stringByExpandingTildeInPath
NSMutableString
+ (id)stringWithCapacity:(unsigned)capacity;
- (void)appendString:(NSString *)aString;
- (void)appendFormat:(NSString *)format, ...;
- (void)deleteCharactersInRange:(NSRange)range;
NSArray
+ (id)arrayWithObjects:(id)firstObj,...;
- (unsigned)count;
- (id)objectAtIndex:(unsigned int) index;
NSMutableArray
+ (id)arrayWithCapacity:(unsigned) numItems;
- (void)addObject:(id)anObject;
- (void)removeObjectAtIndex:(unsigned)index;
- (NSEnumerator *)objectEnumerator;
- (id)nextObject;
/* enumeration */
NSEnumerator *enumerator;
enumerator = [array objectEnumerator];
id thingie;
while(thingie = [enumerator nextObject]) {
NSLog(@"I found %@", thingie);
}
/* Fast Enumeration */
for(NSString *string in array) {
NSLog(@"I found %@", string);
}
NSDictionary
+ (id)dictionaryWithObjectsAndKeys:(id)firstObject, (id)firstKey, ...;
- (id)objectForKey:(id)aKey;
NSMutableDictionary
+ (id)dictionaryWithCapacity:(unsigned int)numItems;
- (void)setObject:(id)anObject forKey:(id)aKey;
- (void)removeObjectForKey:(id)aKey;
because in Cocoa may classes are implemented as class clusters,
don't create subclass to extend, use categories.
NSNumber
+ (NSNumber *)numberWithChar:(char)value;
+ (NSNumber *)numberWithInt:(int)value;
+ (NSNumber *)numberWithFloat:(float)value;
+ (NSNumber *)numberWithBool:(BOOL)value;
- (char)charValue;
- (int)intValue;
- (float)floatValue;
- (BOOL)boolValue;
- (NSString *)stringValue;
NSValue
+ (NSValue *)valueWithBytes:(const void *)value
objCType:(const char *)type;
+ (NSValue *)valueWithPoint:(NSPoint)point;
+ (NSValue *)valueWithSize:(NSSize)size;
+ (NSValue *)valueWithRect:(NSRect)rect;
- (NSPoint)pointValue;
- (NSSize)sizeValue;
- (NSRect)rectValue;
NSNull
+ (NSNull *) null;
NSFileManager
+ (NSFileManager *)defaultManager
- (NSDirectoryEnumerator *)enumeratorAtPath:(NSString *)path
9.0 Memory Management
- Garbage Collection(GC)
If you know that your programs will only be run on Leopard or later, you can take advantage of Objective-C 2.0's garbage collection
- Reference Counting(RC)
Automatic Reference Counting(ARC)
ARC is supported in Xcode 4.2 for OS X v10.6 and v10.7 (64-bit applications) and for iOS 4 and iOS 5.
Weak references are not supported in OS X v10.6 and iOS 4.
Manual Reference Counting(MRC)
- (id)retain; -(oneway void)release;
oneway is used with the distributed objects API, which allows use of objective-c objects between different threads or applications. It tells the system that it should not block the calling thread until the method returns. Without it, the caller will block, even though the method's return type is void. Obviously, it is never used with anything other than void, as doing so would mean the method returns something, but the caller doesn't get it.
- (unsigned)retainCount;
- (id)autorelease;
The Rules of Cocoa Memory Management
+----------------+-------------------------+--------------------------------------------+ |Obtained Via... |Transient |Hang On | +----------------+-------------------------+--------------------------------------------+ |alloc/new/copy |Release when done | Release in dealloc | +----------------+-------------------------+--------------------------------------------+ |Any other way |Don't need to do anything| Retain when acquired, release in dealloc | +----------------+-------------------------+--------------------------------------------+
/* Keeping The Pool Clean */
NSAutoreleasePool *pool;
pool = [[NSAutoreleasePool alloc] init];
int i;
for (i = 0; i < 1000000; i++) {
id object = [someArray objectAtIndex: i];
NSString *desc = [object descrption];
// and do something with the description
if (i % 1000 == 0) {
[pool release];
pool = [[NSAutoreleasePool alloc] init];
}
}
[pool release]
/* Keeping The Pool Clean */
10. Object Initialization
11. Properties
Objective-C 2.0 features can only be used on Mac OS X 10.5 (Leopard) or later
@property
assign retain copy
readonly readwrite
nonatomic
@synthesize
12.Categories
@interface ClassName(CategoryName)
@end //interface ClassName(CategoryName)
@implementation ClassName(CategoryName)
@end //implementation ClassName(CategoryName)
Bad Category
You can not add variables to class.
When names collide, the category wins.
Purpose
split class implementation into multiple files or multiple frameworks
creating forward references for private methods
adding informal protocols to an object
Delegate
delegate is an object asked by another object to do some of its work.
e.g. the AppKit class NSApplication asks its delegate if it should open an Untitled window when the application launches.
@selector(func:)
[obj respondsToSelector:@selector(func:)]
13. Protocols
@protocol FormalProtocolA
- (void)functionA;
@end //protocol FormalProtocolA
@protocol FormalProtocolB
- (void)functionB;
@end //protocol FormalProtocolB
@interface Obj:NSObject
@end //interface Obj
@implementation Obj
- (void)functionA
{
}
- (void)functionB
{
}
@end //interface Obj
A shallow copy
you don't duplicate the referred objects;
you new copy simply points at the referred objects that already exist.
A deep copy
makes duplicates of all the referred objects.
- (id)copyWithZone:(NSZone *)zone
{
return [[[self class] allocWithZone: zone]init];
}
Objective-C 2.0
@optional
@required
