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IOS學(xué)習(xí)筆記十八(copy、mutableCopy、NSCopying、NSMutableCopy、深復(fù)制、淺復(fù)制)
1、 copy、mutableCopy方法
copy方法返回對象的不可修改的副本
mutableCopy方法返回的對象可修改的副本
1)、測試demo
int main(int argc, char * argv[]) {
@autoreleasepool {
NSMutableString *book = [NSMutableString stringWithString:@"chenyu"];
NSMutableString *bookCopy = [book mutableCopy];
[bookCopy replaceCharactersInRange:NSMakeRange(1, 2) withString:@"gong"];
NSLog(@"book is %@", book);
NSLog(@"bookCopy is %@", bookCopy);
NSString *str = @"chenyu";
NSMutableString *strCopy = [str mutableCopy];
[strCopy appendString:@"chenyu"];
NSLog(@"strCopy is:%@", strCopy);
//由于str2是不可變的，所以運行下面會報錯
NSMutableString *str2 = [str copy];
NSLog(@"str copy chen is:%@", str2);
// [str2 appendString:@"chenyu"];
}
}
2)、運行結(jié)果
2018-07-15 19:03:35.564049+0800 cyTest[27254:9418105] book is chenyu
2018-07-15 19:03:35.565157+0800 cyTest[27254:9418105] bookCopy is cgongnyu
2018-07-15 19:03:35.566056+0800 cyTest[27254:9418105] strCopy is:chenyuchenyu
2018-07-15 19:03:35.566857+0800 cyTest[27254:9418105] str copy chen is:chenyu
2、NSCopying、NSMutableCopy協(xié)議
對象調(diào)用copy方法來復(fù)制自身的可變副本，需要類 實現(xiàn)NSCopying協(xié)議，讓該類實現(xiàn)copyWithZone方法
對象調(diào)用mutableCopy方法來復(fù)制自身的可變副本，需要類實現(xiàn)NSMutbaleCopying協(xié)議，讓類實現(xiàn)mutableCopyWithZone方法demo可以看下下面寫的淺復(fù)制
3、深復(fù)制和淺復(fù)制
我個人理解感覺淺復(fù)制是復(fù)制后的屬性(指針變量)指向的地址都是同一塊地址，當(dāng)復(fù)制后的對象屬性值發(fā)生變化的時候，原始值也發(fā)生了變化。
深復(fù)制就是復(fù)制后的屬性(指針變量)指向的地址不是同一塊地址，當(dāng)復(fù)制后的對象屬性值發(fā)生變化的時候，原始值不會發(fā)生變化。
1)、淺復(fù)制測試Demo
Dog.h
#import <Foundation/Foundation.h>
#ifndef Dog_h
#define Dog_h
@interface Dog : NSObject<NSCopying>
@property (nonatomic, strong) NSMutableString *name;
@property (nonatomic, assign) int age;
@end
#endif /* Dog_h */
Dog.m
#import <Foundation/Foundation.h>
#import "Dog.h"
@implementation Dog
@synthesize name;
@synthesize age;
-(id)copyWithZone:(NSZone *)zone
{
Dog *dog = [[[self class] allocWithZone:zone] init];
dog.name = self.name;
dog.age = self.age;
return dog;
}
@end
main.m
Dog *dog1 = [Dog new];
dog1.name = [NSMutableString stringWithString:@"chen"];
dog1.age = 1;
NSLog(@"dog1.name is %@ and age is %d", dog1.name, dog1.age);
//淺復(fù)制
Dog *dog2 = [dog1 copy];
// dog2.name = [NSMutableString stringWithString:@"li"];
[dog2.name replaceCharactersInRange:NSMakeRange(1, 2) withString:@"hel"];
dog2.age = 20;
NSLog(@"dog2.name is %@ and age is %d", dog2.name, dog2.age);
NSLog(@"dog1.name is %@ and age is %d", dog1.name, dog1.age);
2)、運行結(jié)果
2018-07-15 19:03:35.567556+0800 cyTest[27254:9418105] dog1.name is chen and age is 1
2018-07-15 19:03:35.567690+0800 cyTest[27254:9418105] dog2.name is cheln and age is 20
2018-07-15 19:03:35.567768+0800 cyTest[27254:9418105] dog1.name is cheln and age is 1
3)、深復(fù)制Demo
Dog.h文件一樣
Dog.m文件有點變化
#import <Foundation/Foundation.h>
#import "Dog.h"
@implementation Dog
@synthesize name;
@synthesize age;
-(id)copyWithZone:(NSZone *)zone
{
Dog *dog = [[[self class] allocWithZone:zone] init];
// dog.name = self.name;
dog.name = [self.name mutableCopy];
dog.age = self.age;
return dog;
}
@end
main.m文件一樣
Dog *dog1 = [Dog new];
dog1.name = [NSMutableString stringWithString:@"chen"];
dog1.age = 1;
NSLog(@"dog1.name is %@ and age is %d", dog1.name, dog1.age);
//深復(fù)制
Dog *dog2 = [dog1 copy];
// dog2.name = [NSMutableString stringWithString:@"li"];
[dog2.name replaceCharactersInRange:NSMakeRange(1, 2) withString:@"hel"];
dog2.age = 20;
NSLog(@"dog2.name is %@ and age is %d", dog2.name, dog2.age);
NSLog(@"dog1.name is %@ and age is %d", dog1.name, dog1.age);
4)、運行結(jié)果
2018-07-15 19:13:08.751335+0800 cyTest[27529:9427019] dog1.name is chen and age is 1
2018-07-15 19:13:08.751686+0800 cyTest[27529:9427019] dog2.name is cheln and age is 20
2018-07-15 19:13:08.751885+0800 cyTest[27529:9427019] dog1.name is chen and age is 1
4、setter方法的復(fù)制選項
我們setter方法復(fù)制選項的時候，如果加了copy屬性，比如setName方法
-(void)setName : (NSMutableStrinfg *)name
{
self.name = [name copy];
}
#import <Foundation/Foundation.h>
#import "Dog.h"
@implementation Dog
@synthesize name;
@synthesize age;
@end
所以當(dāng)對象設(shè)置了name屬性的話，就不能再改變了，如下demo
Dog.h
#import <Foundation/Foundation.h>
#ifndef Dog_h
#define Dog_h
@interface Dog : NSObject
@property (nonatomic, copy) NSMutableString *name;
@property (nonatomic, assign) int age;
@end
#endif /* Dog_h */
Dog.m
#import <Foundation/Foundation.h>
#import "Dog.h"
@implementation Dog
@synthesize name;
@synthesize age;
@end
main.m
Dog *dog1 = [Dog new];
dog1.name = [NSMutableString stringWithString:@"chen"];
dog1.age = 1;
[dog1.name appendString:@"hello"];
運行結(jié)果
2018-07-15 19:22:17.736557+0800 cyTest[27853:9436238] -[NSTaggedPointerString appendString:]: unrecognized selector sent to instance 0xa0000006e6568634
2018-07-15 19:22:17.739655+0800 cyTest[27853:9436238] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSTaggedPointerString appendString:]: unrecognized selector sent to instance 0xa0000006e6568634'
*** First throw call stack:
(
0 CoreFoundation 0x0000000104fd61e6 __exceptionPreprocess + 294
1 libobjc.A.dylib 0x000000010466b031 objc_exception_throw + 48
2 CoreFoundation 0x0000000105057784 -[NSObject(NSObject) doesNotRecognizeSelector:] + 132
3 CoreFoundation 0x0000000104f58898 ___forwarding___ + 1432
4 CoreFoundation 0x0000000104f58278 _CF_forwarding_prep_0 + 120
5 cyTest 0x0000000103d60438 main + 600
6 libdyld.dylib 0x0000000108a2f955 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
很明顯，報錯了。
作者：chen.yu
深信服三年半工作經(jīng)驗，目前就職游戲廠商，希望能和大家交流和學(xué)習(xí),
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