一 概述
上篇文章简单介绍了内存管理set的基本方法，可是依然有不太完善的地方，如给一个类成员通过set方法设置另一个类成员时及多次设置时，如何避免内存泄漏呢？
二 代码实例
2.1 类实例(Car)
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| //Car.h
#import <Foundation/Foundation.h>
@interface Car : NSObject
{
int _speed;
}
-(void)setSpeed:(int)speed;
-(int)speed;
//Car.m
#import "Car.h"
@implementation Car
- (void)setSpeed:(int)speed
{
_speed=speed;
}
-(int)speed
{
return _speed;
}
-(void)dealloc
{
NSLog(@"速度为%d的Car对象被回收了",self.speed);
[super dealloc];
}
@end
|
2.2 类实例(Person)
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| //Person.h
#import <Foundation/Foundation.h>
#import "Car.h"
@interface Person : NSObject
{
Car *_car;
int _age;
}
-(void)setCar:(Car*)car;
-(Car*)car;
-(void)setAge:(int)age;
-(int)age;
@end
//Person.m
#import "Person.h"
@implementation Person
- (void)setCar:(Car *)car
{
if(car!=_car)
{
[_car release];
_car=[car retain];
//_car=car;
}
}
-(Car *)car
{
return _car;
}
-(void)setAge:(int)age
{
_age=age;
}
-(int)age
{
return _age;
}
-(void)dealloc
{
[_car release];
NSLog(@"Person对象被回收了");
[super dealloc];
}
@end
|
2.3 main.m(运行)
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| #import <Foundation/Foundation.h>
#import "Person.h"
#import "Car.h"
int main(int argc, const char * argv[]) {
@autoreleasepool {
// insert code here...
// Person *p=[[Person alloc]init];
// p.age=20;
// Car *c1=[[Car alloc]init];
// c1.speed=250;
// p.car=c1;
//
// Car *c2=[[Car alloc]init];
// c2.speed=300;
// p.car=c2;
//
// [c2 release];
// [c1 release];
// [p release];
Person *p=[[Person alloc]init];
p.age=20;
Car *c1=[[Car alloc]init];
c1.speed=250;
p.car=c1;
[c1 release];
p.car=c1;
p.car=c1;
[p release];
}
return 0;
}
|