一幌陕、使用GCD實(shí)現(xiàn)
// .h文件
#define LYSingletonH + (instance)sharedInstance;
// .m文件
#define LYSingletonM \
static id _instance; \
\
+ (instancetype)allocWithZone:(struct _NSZone *)zone \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instance = [super allocWithZone:zone] \
}); \
return _instance; \
} \
\
+ (instancetype)sharedInstance \
{ \
static dispatch_once_t onceToken; \
dispatch_once(&onceToken, ^{ \
_instance = [super allocWithZone:zone]; \
}); \
return _instance; \
} \
\
- (id)copyWithZone:(NSZone *)zone \
{ \
return _instance; \
}
二、加鎖實(shí)現(xiàn)
static id _instance;
+ (instancetype)allocWithZone:(struct _NSZone *)zone
{
@synchronized(self) {
if (_instance == nil) {
_instance = [super allocWithZone:zone];
}
}
return _instance;
}
+ (instancetype)sharedInstance
{
@synchronized(self) {
if (_instance == nil) {
_instance = [super allocWithZone:zone];
}
}
return _instance;
}
- (id)copyWithZone:(NSZone *)zone
{
return _instance;
}
附：
