IOS阶段学习第21天笔记(ARC内存管理-Copy-代理)

 1 //main.m中的代码
 2 Person *p1=[[Person alloc]init];
 3 //上一个对象没有强引用指向，内存会被释放掉
 4 p1=[[Person alloc]init];
 5 NSLog(@"********");
 6 //错误的写法，表明有一个弱引用指向对象，这条语句执行完毕后对象就被释放了
 7 __weak Person *p2=[[Person alloc]init];
 8 NSLog(@"+++=======");
 9 
10 //Person.h中的代码
11 #import <Foundation/Foundation.h>
12 @class Card;
13 @interface Person : NSObject
14 @property(nonatomic,strong)Card *card;
15 @property(nonatomic,strong)NSString *name;
16 @property(nonatomic,assign)int age;
17 @end
18 
19 //Card.h中的代码
20 #import <Foundation/Foundation.h>
21 #import "Person.h"
22 @interface Card : NSObject
23 @property(nonatomic,weak)Person *person;
24 @end

 1 NSString *str1=@"Hello";
 2 NSString *str2=str1;
 3 //对不可变字符串发送copy消息会得到一个新的不可变字符串
 4 NSString *str3=[str1 copy]; 
 5 // [str3 appendString:@" shanghai"];
 6 //对不可变字符串发送mutableCopy消息后会得到一个新的可变字符串
 7 NSMutableString *str4=[str1 mutableCopy];
 8 [str4 appendString:@" beijing"];
 9 NSLog(@"str4:%@",str4);
10 NSMutableString *mStr1=[NSMutableString stringWithString:str1];
11 //对可变字符串发送copy消息会得到一个新的不可变字符串
12 NSString *mStr2=[mStr1 copy];
13 //[mStr2 appendString:@"aaa"];
14 
15 //对可变字符串发送mutableCopy消息会得到一个新的可变字符串对象
16 NSMutableString *mStr3=[mStr1 mutableCopy];
17 [mStr3 appendString:@"abc"];
18 NSLog(@"mStr3=%@",mStr3);

1 #import <Foundation/Foundation.h> 
2 @interface QFCar : NSObject<NSCopying>
3 @property(nonatomic,copy)NSString *name;
4 @property(nonatomic,assign)int year;
5 -(void)print;
6 @end

 1 #import "QFCar.h" 
 2 @implementation QFCar
 3 //调用copy方法时会执行此协议方法
 4 - (id)copyWithZone:(NSZone *)zone
 5 {
 6     //QFCar *car=[[QFCar allocWithZone:zone]init];
 7    //可以被子类继承，copy出来的就是子类的对象
 8     //[self class]获取当前的类（对象）
 9     QFCar *car=[[[self class] allocWithZone:zone]init];
10     car.name=self.name;
11     car.year=self.year;
12     return car;
13 }
14 
15 -(void)print
16 {
17 
18     NSLog(@"name is %@, year is %d",_name,_year);
19 }
20 @end

1 QFCar *mCar=[[QFCar alloc]init];
2 NSString *n1=@“宝马X6”;
3 NSMutableString *n=[[NSMutableString alloc]initWithString:n1];
4 mCar.name=n;
5 mCar.year=2015;
6 [mCar print];
7 [n appendString:@" kingkong"];
8 [mCar print];

 1 NSMutableArray *carList=[[NSMutableArray alloc]init];
 2 for(int i=0;i<5;i++){
 3 QFCar *car=[[QFCar alloc]init];//自定义的类对象
 4 car.name=[NSString stringWithFormat:@“宝马X%d”,i+1];
 5 car.year=2011+i;
 6 [carList addObject:car];
 7 }
 8 
 9  //使用copy(mutableCopy)实现的是数组的浅拷贝（只拷贝数组对象，2个数组对象存放的是相同元素的地址，数组中的元素对象并没有被拷贝）
10 //NSMutableArray *array1=[carList mutableCopy];
11 
12  //浅拷贝
13 NSMutableArray *array1=[[NSMutableArray alloc]initWithArray:carList];
14 
15 //实现数组的深拷贝（不仅拷贝数组对象，数组中存放的元素对象也将被拷贝一份新的）
16 NSMutableArray *array2=[[NSMutableArray alloc]initWithArray:carList copyItems:YES];
17 [[array2 lastObject] setName:@"shanghai"];
18 for(QFCar *car in array2){
19 [car print];
20 }
21 NSLog(@"***********");
22 for(QFCar *car in carList){
23 [car print];
24 }

1 #import <Foundation/Foundation.h> 
 2 @protocol MasterDelegate<NSObject>
 3 -(void)examine;
 5 -(void)meeting;
 7 -(void)travle;
 9 @end
11 @interface HeadMaster : NSObject
13 @property(nonatomic,strong)id<MasterDelegate> delegate;
15 -(void)masterExamine;
17 -(void)masterMeeting;
19 -(void)masterTravle;
21 @end

 1 #import "HeadMaster.h" 
 2 @implementation HeadMaster
 3 -(void)masterExamine
 4 {
 5      if([_delegate conformsToProtocol:@protocol(MasterDelegate)]){
 6         if([_delegate respondsToSelector:@selector(examine)]){
 7             [_delegate examine];
 8         }
 9     }
10 } 
12 -(void)masterMeeting
13 {
14     if([_delegate conformsToProtocol:@protocol(MasterDelegate)]){
15         if([_delegate respondsToSelector:@selector(meeting)]){
16             [_delegate meeting];
17         }
18     }
19 }
20 
21 -(void)masterTravle
22 {
23     if([_delegate conformsToProtocol:@protocol(MasterDelegate)]){
24         if([_delegate respondsToSelector:@selector(travle)]){
25             [_delegate travle];
26         }
27     }
28 }
29 @end

1 #import <Foundation/Foundation.h>
2 #import "HeadMaster.h"
3 @interface Teacher : NSObject<MasterDelegate>
4 @end

 1 #import "Teacher.h"
 2 @implementation Teacher
 3 -(void)examine
 4 {
 5     NSLog(@"teacher examine");
 6 }
 7 
 8 -(void)meeting
 9 {
10     NSLog(@"teacher meeting");
11 }
12 
13 -(void)travle
14 {
15     NSLog(@"teacher travle");
16 }
17 @end

 1 #import <Foundation/Foundation.h>
 2 #import "Teacher.h"
 3 int main(int argc, const char * argv[]) {
 4     @autoreleasepool {
 5         HeadMaster *master=[[HeadMaster alloc]init];
 6         Teacher *xiaozhang=[[Teacher alloc]init];
 7         master.delegate=xiaozhang;
 8         [master masterExamine];
 9         [master masterMeeting];
10         [master masterTravle];
11     }
12     return 0;
13 }