ObjectiveC 对象复制 迎客

Foundation系统对象（NSString,NSArray等）

只有遵守NSCopying 协议的类才可以发送copy消息
只有遵守 NSMutableCopying 协议的类才可以发送mutableCopy消息

copy和mutableCopy区别就是copy返回后的是不能修改的对象, 而mutableCopy返回后是可以修改的对象。

这个两个方法复制的对象都需要手动释放。

自义定义Class

自义定Class也需要实现NSCopying协义或NSMutableCopying协议后，其对象才能提供copy功能。

//TestProperty.h
#import <Cocoa/Cocoa.h>


@interface TestProperty : NSObject <NSCopying>{
  NSString *name;
  NSString *password;
  NSMutableString *interest;
  NSInteger myInt;
}

@property (retain,nonatomic) NSString *name,*password;
@property (retain,nonatomic) NSMutableString *interest;
@property NSInteger myInt;

-(void) rename:(NSString *)newname;

@end

//TestProperty.m
#import "TestProperty.h"


@implementation TestProperty

@synthesize name,password,interest;
@synthesize myInt;

-(void) rename:(NSString *)newname{
  // 这里可以直接写成
  // self.name = newname;
  //
  if (name != newname) {
    [name autorelease];
    name = newname;
    [name retain];
  }
}

-(void) dealloc{
  self.name = nil;
  self.password = nil;
  self.interest = nil;
  [super dealloc];
}
- (id)copyWithZone:(NSZone *)zone{
  TestProperty *newObj = [[[self class] allocWithZone:zone] init];
  newObj.name = name;
  newObj.password = password;
  newObj.myInt = myInt;
  //深复制
  NSMutableString *tmpStr = [interest mutableCopy];
  newObj.interest = tmpStr;
  [tmpStr release];
  
  //浅复制
  //newObj.interest = interest;
  return newObj;
}
@end