我有一个单例名称CoreDataManager，它在其中注册了mergeContextChangesForNotification:+(id)sharedManager{staticCoreDataManager*mSharedManager=nil;staticdispatch_once_tonceToken;dispatch_once(&onceToken,^{mSharedManager=[[CoreDataManageralloc]init];});returnmSharedManager;}-(id)init{self=[superinit];if(self){dispatc