Objective - C 一一 宏定义抽取单例

不熟悉单例的朋友,请先看Objective-C -- 单例设计模式

宏定义抽取单例,顾名思义,使用宏定义来替代单例的代码.这样我们以后写单例,有这个写好的单例代码的文件即可.

话不多少直接上代码.

这个文件保存的就是单例的代码,这里使用宏定义来替代这些代码

Singleton.h文件:

// 以后就可以使用interfaceSingleton来替代后面方法的声明
#define interfaceSingleton(name)  +(instancetype)share##name

#if __has_feature(objc_arc)
// ARC
#define implementationSingleton(name)  \
+ (instancetype)share##name \
{ \
name *instance = [[self alloc] init]; \
return instance; \
} \
static name *_instance = nil; \
+ (instancetype)allocWithZone:(struct _NSZone *)zone \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instance = [[super allocWithZone:zone] init]; \
}); \
return _instance; \
} \
- (id)copyWithZone:(NSZone *)zone{ \
return _instance; \
} \
- (id)mutableCopyWithZone:(NSZone *)zone \
{ \
return _instance; \
}
#else

// MRC
#define implementationSingleton(name)  \
+ (instancetype)share##name \
{ \
name *instance = [[self alloc] init]; \
return instance; \
} \
static name *_instance = nil; \
+ (instancetype)allocWithZone:(struct _NSZone *)zone \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instance = [[super allocWithZone:zone] init]; \
}); \
return _instance; \
} \
- (id)copyWithZone:(NSZone *)zone{ \
return _instance; \
} \
- (id)mutableCopyWithZone:(NSZone *)zone \
{ \
return _instance; \
} \
- (oneway void)release \
{ \
} \
- (instancetype)retain \
{ \
return _instance; \
} \
- (NSUInteger)retainCount \
{ \
return  MAXFLOAT; \
}
#endif

Tools 文件

#import 
#import "Singleton.h"
@interface Tools : NSObject 

interfaceSingleton(Tools);

@end


@implementation Tools

implementationSingleton(Tools)

@end

Person 文件

#import 
#import "Singleton.h"
@interface Person : NSObject

interfaceSingleton(Person);

@end


@implementation Person

implementationSingleton(Person);

@end

main文件

#import 
#import "Tools.h"
#import "Person.h"
int main(int argc, const char * argv[]) {

     Tools *t1 = [[Tools alloc] init]; //内部会调用 allocWithZone
     Tools *t2 = [Tools new];// [[alloc] init]  allocWithZone
     Tools *t3 = [Tools shareTools];
     Tools *t4 = [t3 copy];
     Tools *t5 = [t3 mutableCopy];
    NSLog(@"%p, %p, %p, %p, %p", t1, t2, t3, t4, t5);
    
    Person *p1 = [Person sharePerson];
    Person *p2 = [Person sharePerson];
    NSLog(@"%p, %p", p1, p2);
 
    
    // 如何判断当前是ARC还是MRC
    // 可以在编译的时候判断当前是否是ARC
#if __has_feature(objc_arc)
    NSLog(@"ARC");
#else
    NSLog(@"MRC");
#endif
    return 0;
}

输出结果:

2017-07-30 23:32:06.001955+0800 宏定义抽取单例[5759:221243] 0x100403420, 0x100403420, 0x100403420, 0x100403420, 0x100403420
2017-07-30 23:32:06.002197+0800 宏定义抽取单例[5759:221243] 0x100303bd0, 0x100303bd0
2017-07-30 23:32:06.002215+0800 宏定义抽取单例[5759:221243] ARC

我把项目调成MRC后的输出结果:

2017-07-30 23:32:57.144990+0800 宏定义抽取单例[5783:221591] 0x100200160, 0x100200160, 0x100200160, 0x100200160, 0x100200160
2017-07-30 23:32:57.145242+0800 宏定义抽取单例[5783:221591] 0x100500310, 0x100500310
2017-07-30 23:32:57.145266+0800 宏定义抽取单例[5783:221591] MRC

这样就大功告成了,以后我们写单例.只需要Singleton.h文件即可.对ARC 和 MRC 项目都管用!