可以设置最⼤大并发数 @interface NSOperationQueue : NSObject { - (void)addOperation:(NSOperation *)op; - (void)addOperations:(NSArray *)ops waitUntilFinished: (BOOL)wait - (void)addOperationWithBlock:(void (^)(void))block NS_AVAILABLE(10_6, 4_0); - (NSArray *)operations; - (NSUInteger)operationCount NS_AVAILABLE(10_6, 4_0); - (NSInteger)maxConcurrentOperationCount; - (void)setMaxConcurrentOperationCount:(NSInteger)cnt; - (void)setSuspended:(BOOL)b; - (BOOL)isSuspended; - (void)setName:(NSString *)n NS_AVAILABLE(10_6, 4_0); - (NSString *)name NS_AVAILABLE(10_6, 4_0); - (void)cancelAllOperations; - (void)waitUntilAllOperationsAreFinished; + (id)currentQueue NS_AVAILABLE(10_6, 4_0); + (id)mainQueue NS_AVAILABLE(10_6, 4_0); @end 13年1月17⽇日星期四