OC单例快速实现

首先新建一个头文件,定义如下宏:

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// .h文件的实现 #define SingletonH(methodName) + (instancetype)shared##methodName;   // .m文件的实现 #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

然后在你定义单例类的

.h 文件 写 SingletonH(MyMethodName) 

.m 文件写 SingletonM(MyMethodName)

搞定!