一句話實現OC單例模式,一句話實現OC模式
首先建立一個標頭檔,定義如下宏:
// .h檔案的實現#define SingletonH(methodName) + (instancetype)shared##methodName;// .m檔案的實現#if __has_feature(objc_arc) // 是ARC#define SingletonM(methodName) \static id _instace = nil; \+ (id)allocWithZone:(struct _NSZone *)zone \{ \if (_instace == nil) { \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [super allocWithZone:zone]; \}); \} \return _instace; \} \\- (id)init \{ \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [super init]; \}); \return _instace; \} \\+ (instancetype)shared##methodName \{ \return [[self alloc] init]; \} \+ (id)copyWithZone:(struct _NSZone *)zone \{ \return _instace; \} \\+ (id)mutableCopyWithZone:(struct _NSZone *)zone \{ \return _instace; \}#else // 不是ARC#define SingletonM(methodName) \static id _instace = nil; \+ (id)allocWithZone:(struct _NSZone *)zone \{ \if (_instace == nil) { \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [super allocWithZone:zone]; \}); \} \return _instace; \} \\- (id)init \{ \static dispatch_once_t onceToken; \dispatch_once(&onceToken, ^{ \_instace = [super init]; \}); \return _instace; \} \\+ (instancetype)shared##methodName \{ \return [[self alloc] init]; \} \\- (oneway void)release \{ \\} \\- (id)retain \{ \return self; \} \\- (NSUInteger)retainCount \{ \return 1; \} \+ (id)copyWithZone:(struct _NSZone *)zone \{ \ return _instace; \} \ \+ (id)mutableCopyWithZone:(struct _NSZone *)zone \{ \ return _instace; \}#endif
然後在你定義單例類的
.h 檔案 寫 SingletonH(MyMethodName)
.m 檔案寫 SingletonM(MyMethodName)
搞定!