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一.MRC模式下set和get方法
首先我们创建一个Dog类
Dog.h:
#import <Foundation/Foundation.h> @interface Dog : NSObject @property (assign) int ID; @end
Dog.m:
#import "Dog.h"
@implementation Dog
@synthesize ID = _ID;
- (void)dealloc{
NSLog(@"Dog ID%d is death",_ID);
[super dealloc];
}
@end
再创建一饿Person类
Person.h:
#import <Foundation/Foundation.h>
#import "Dog.h"
@interface Person : NSObject
{
Dog *_dog;
}
-(void)setDog:(Dog *)newDog;
-(Dog *)dog;
@end
Person.m:
#import "Person.h"
@implementation Person
-(void)setDog:(Dog *)newDog{
NSLog(@"%d",_dog.retainCount);
if(_dog != newDog){
[_dog release];
_dog = nil;
NSLog(@"%d",_dog.retainCount);
_dog = [newDog retain];
NSLog(@"%d",_dog.retainCount);
}
}
-(Dog *)dog{
return [_dog autorelease];
}
- (void)dealloc
{
NSLog(@"Person is death");
[super dealloc];
}
@end
在main函数中我们创建两个dog,并且创建person
Dog *dog1 = [[Dog alloc]init];
dog1.ID = 1;
Dog *dog2 = [[Dog alloc]init];
dog2.ID = 2;
Person *p = [[Person alloc]init];
person set一个dog
[p setDog:dog1];
此时，set方法完之后dog.retainCount值为2，因为dog创建和retain
当我们把dog1 release操作
[dog1 release];
NSLog(@"%d",dog1.retainCount); //值为1
NSLog(@"%zd",p.retainCount); //person的retainCount值为1，因为只是创建
我们把person release操作
[p release];
p = nil;
此时person retainCount值为0,并且调用了dealloc方法,但是person里的dog的retainCount值为1;所以我们在回收person时要把它的对象属性release操作,要不会引起内存空间的泄漏
当person没有执行release操作，再set一个dog1操作，此时，person的dog的retainCount值为1，即没有进行retain操作
注意点：
1.析构函数的release时一定要release掉包含的对象
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原文地址：http://www.cnblogs.com/kaihuacheng/p/5624274.html
