调度组

1. despatch_group_t group = dispatch_group_create();

2. dispatch_queue_t queue = dispatch_queue_get_globalQuequ();

3. dispatch_enter_group(group);

4. dispatch_group_async(quequ

　　NSLog(@"耗时操作1");

　　dispatch_leave_group(group);

);

5. dispatch_enter_group(group);

dispatch_group_async(quequ

　　NSLog(@"耗时操作2");

　　dispatch_leave_group(group);

);

6. dispatch_notify(

);

https://blog.csdn.net/u010105969/article/details/69668841