iOS开发之GCD - Group

开发中经常遇到这样的情况，需要两个线程执行完毕再操作。直接上示例代码

  dispatch_group_t  group = dispatch_group_create();
dispatch_group_async(group, dispatch_get_global_queue(0, 0), ^{
    [NSThread sleepForTimeInterval:5];
    NSLog(@"线程一");
});
dispatch_group_async(group, dispatch_get_global_queue(0, 0), ^{
    
    [NSThread sleepForTimeInterval:10];
    NSLog(@"线程二");
});
dispatch_group_notify(group, dispatch_get_global_queue(0, 0), ^{
    NSLog(@"线程一二都执行完毕");
});