你可能喜欢
单项选择题
A.-(instancetype)initWithTarget:(id)target selector:(SEL)selector object:(id)argument
B.+(void)detachNewThreadSelector:(SEL)selector to Target:(id)target with Object:(id)argument;
C.-(void)performSelectorInBackground:(SEL)aSelector withObject:(id)arg;正
D.+(NSThread*)mainThread;
多项选择题
A.willHideViewController:
B.willShowViewController:
C.shouldHideViewController:
D.willPresentViewController:
单项选择题
A.BOOL executing;//判断任务是否正在执行
B.BOOL finished;//判断任务是否完成
C.void(^completionBlock)(void);//用来设置完成后需要执行的操作
D.-(void)waitUntilFinished;//取消任务
单项选择题
A.[operation1 addDependency:operation2];
B.[operation addExecutionBlock:^{}];
C.[operation waitUntilFinished];
D.[operation cancel];