oc单例的快速创建

oc工程中 都会用到单例模式进行应用中数据的存储，然而在创建单例的过程会比较的繁琐 需要区分MRC 与ARC 给大家分享一个快速的方法 直接上代码 

#if __has_feature(objc_arc)

#define     MYOBJECT_SINGLETON_FOR_CLASS(classname) \

\

static classname *shared##classname = nil; \

\

+ (classname *)shared##classname \

{ \

@synchronized(self) \

{ \

if (shared##classname == nil) \

{ \

shared##classname = [[self alloc] init]; \

} \

} \

\

return shared##classname; \

} \

\

+ (id)allocWithZone:(NSZone *)zone \

{ \

@synchronized(self) \

{ \

if (shared##classname == nil) \

{ \

shared##classname = [super allocWithZone:zone]; \

return shared##classname; \

} \

} \

\

return nil; \

} \

\

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

{ \

return self; \

} \

#else

#define SYNTHESIZE_SINGLETON_FOR_CLASS(classname) \

\

static classname *shared##classname = nil; \

\

+ (classname *)shared##classname \

{ \

@synchronized(self) \

{ \

if (shared##classname == nil) \

{ \

shared##classname = [[self alloc] init]; \

} \

} \

\

return shared##classname; \

} \

\

+ (id)allocWithZone:(NSZone *)zone \

{ \

@synchronized(self) \

{ \

if (shared##classname == nil) \

{ \

shared##classname = [super allocWithZone:zone]; \

return shared##classname; \

} \

} \

\

return nil; \

} \

\

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

{ \

return self; \

} \

\

- (id)retain \

{ \

return self; \

} \

\

- (NSUInteger)retainCount \

{ \

return NSUIntegerMax; \

} \

\

- (oneway void)release \

{ \

} \

\

- (id)autorelease \

{ \

return self; \

}

#endif