第十六讲：Objective-C内存管理之“黄金法则”
Person.h////Person.h
//memory
//
//Created by yusian on 14-1-11.
//Copyright (c) 2014年 yusian. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "Dog.h"
@interface Person : NSObject
{
Dog * _dog;
}
- (void) setDog:(Dog *)aDog;
- (Dog *) dog;
@end
Person.m
//
//Person.m
//memory
//
//Created by yusian on 14-1-11.
//Copyright (c) 2014年 yusian. All rights reserved.
//
#import "Person.h"
@implementation Person
- (Dog *) dog{
return _dog;
}
- (void) setDog:(Dog *)aDog{
if (aDog != _dog) {
;
_dog = ;
}
}
- (void) dealloc{
NSLog(@"Person is dealloc!");
;
;
}
@end
Dog.h
//
//Dog.h
//memory
//
//Created by yusian on 14-1-11.
//Copyright (c) 2014年 yusian. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface Dog : NSObject
{
int _ID;
}
@property int ID;
@end
Dog.m
//
//Dog.m
//memory
//
//Created by yusian on 14-1-11.
//Copyright (c) 2014年 yusian. All rights reserved.
//
#import "Dog.h"
@implementation Dog
@synthesize ID = _ID;
- (void) dealloc{
NSLog(@"Dog %d is dealloc!",_ID);
;
}
@end
main.m
//
//main.m
//memory
//
//Created by yusian on 14-1-11.
//Copyright (c) 2014年 yusian. All rights reserved.
//
#import <Foundation/Foundation.h>
#import "Dog.h"
#import "Person.h"
int main(int argc, const char * argv[])
{
@autoreleasepool {
Dog * dog1 = [ init];
Dog * dog2 = [ init];
Person * sim = [ init];
Person * sian = [ init];
;
;
NSLog(@"//初始化两条狗");
NSLog(@"dog %d retainCount1 is %ld",,);
NSLog(@"dog %d retainCount1 is %ld",,);
;//sim开始遛狗dog1
NSLog(@"//sim开始遛狗dog1");
NSLog(@"dog %d retainCount2 is %ld",,);
NSLog(@"dog %d retainCount2 is %ld",,);
;//sian开始遛狗dog1
NSLog(@"//sian开始遛狗dog1");
NSLog(@"dog %d retainCount3 is %ld",,);
NSLog(@"dog %d retainCount3 is %ld",,);
;//sim开始遛狗dog2
NSLog(@"//sim开始遛狗dog2");
NSLog(@"dog %d retainCount4 is %ld",,);
NSLog(@"dog %d retainCount4 is %ld",,);
;//sian开始遛狗dog2
NSLog(@"//sian开始遛狗dog2");
NSLog(@"dog %d retainCount5 is %ld",,);
NSLog(@"dog %d retainCount5 is %ld",,);
;//sim离开
NSLog(@"//sim离开");
NSLog(@"dog %d retainCount6 is %ld",,);
NSLog(@"dog %d retainCount6 is %ld",,);
;//sian离开
NSLog(@"//sian离开");
NSLog(@"dog %d retainCount7 is %ld",,);
NSLog(@"dog %d retainCount7 is %ld",,);
NSLog(@"//dog1 and dog2 is release");
;
;
}
return 0;
}
输出结果：
2014-01-11 23:08:52.260 memory //初始化两条狗
2014-01-11 23:08:52.261 memory dog 1 retainCount1 is 1
2014-01-11 23:08:52.261 memory dog 2 retainCount1 is 1
2014-01-11 23:08:52.262 memory //sim开始遛狗dog1
2014-01-11 23:08:52.262 memory dog 1 retainCount2 is 2
2014-01-11 23:08:52.262 memory dog 2 retainCount2 is 1
2014-01-11 23:08:52.263 memory //sian开始遛狗dog1
2014-01-11 23:08:52.263 memory dog 1 retainCount3 is 3
2014-01-11 23:08:52.263 memory dog 2 retainCount3 is 1
2014-01-11 23:08:52.264 memory //sim开始遛狗dog2
2014-01-11 23:08:52.264 memory dog 1 retainCount4 is 2
2014-01-11 23:08:52.264 memory dog 2 retainCount4 is 2
2014-01-11 23:08:52.265 memory //sian开始遛狗dog2
2014-01-11 23:08:52.265 memory dog 1 retainCount5 is 1
2014-01-11 23:08:52.265 memory dog 2 retainCount5 is 3
2014-01-11 23:08:52.266 memory Person is dealloc!
2014-01-11 23:08:52.266 memory //sim离开
2014-01-11 23:08:52.266 memory dog 1 retainCount6 is 1
2014-01-11 23:08:52.267 memory dog 2 retainCount6 is 2
2014-01-11 23:08:52.267 memory Person is dealloc!
2014-01-11 23:08:52.267 memory //sian离开
2014-01-11 23:08:52.268 memory dog 1 retainCount7 is 1
2014-01-11 23:08:52.268 memory dog 2 retainCount7 is 1
2014-01-11 23:08:52.268 memory //dog1 and dog2 is release
2014-01-11 23:08:52.269 memory Dog 1 is dealloc!
2014-01-11 23:08:52.269 memory Dog 2 is dealloc!
Program ended with exit code: 0
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