【Demo 0025】FoundationKit 深浅拷贝

一、深浅拷贝

浅复制 -- 一个对象赋值给另一个对象，实际上就是指针复制，当一个内容发生变化时别一个也会发生变化;

深复制 -- 一个对象内容拷贝给别一个对象，深复制后两个对象都是相互独立的，互不影响;

二、自定义类型实现深拷贝

实现深拷贝方法：主要实现NSCopying协议的copyWithZone方法， 代码模型

@interface className : NSObject<NSCopying>

@property (nonatomic, copy) NSString* name;

-(id) copyWithZone: (NSCopying)zone;

@end

 

@implementation

（id) copyWithZone: (NSCopying)zone

{

　　内成员深复制

} 

@end

三、练习代码

@interface Book : NSObject<NSCopying>

{

    NSMutableString*   _name;

    NSString*   _isbn;

    NSUInteger  _price;

}

@property(nonatomic, copy) NSString*    _name;

@property(nonatomic, copy) NSString*    _isbn;

@property(nonatomic, assign) NSUInteger _price;

 

-(id) init;

-(void) print:(NSString*)prompt;

-(id) copyWithZone:(NSZone*)zone;

@end

 

 

@implementation Book

 

@synthesize _name;

@synthesize _isbn;

@synthesize _price;

 

-(id) init

{

    if (self = [super init])

    {

        _name   = @"";

        _isbn   = @"";

        _price  = 0;

    }

    returnself;

}

 

-(void) print:(NSString*)prompt

{

    NSLog(@"\n%@\nname: %@\nisbn: %@\nprice: %lu", prompt, _name, _isbn, _price);

}

 

-(id) copyWithZone:(NSZone*)zone

{

    Book* book = [[Book allocWithZone:zone]init];

    

    [book set_name:_name];

    [book set_isbn:_isbn];

    [book set_price:_price];

    

    return book;

}

 

@end

int main(int argc, const char * argv[])

{

    @autoreleasepool {

        Book* book = [[Book alloc]init];

        NSMutableString* name = [NSMutableStringstringWithString:@"ztercel objective-c"];

        [book set_name:name];

        [book set_isbn:@"978-7-126-14974-10"];

        [book set_price:89.0];

        [book print:@"create book:"];

        

        [name appendFormat:@"i do"];  

        [book print:@"after modify name source data, book data:"];

 

        Book* book2 = [book copy]; // book;

        [book2 set_name:@"objective-c programming"];

        [book2 set_price:100];

        [book2 print:@"book2 value: "];

        [book print:@"book value: "];

}

 

演示实例