dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_group_t?group?=?dispatch_group_create();
dispatch_group_async(group,?queue,?^{
[NSThread?sleepForTimeInterval:1];
NSLog(@"group1");
});
dispatch_group_async(group,?queue,?^{
[NSThread?sleepForTimeInterval:2];
NSLog(@"group2");
});
dispatch_group_async(group,?queue,?^{
[NSThread?sleepForTimeInterval:3];
NSLog(@"group3");
});
dispatch_group_notify(group,?dispatch_get_main_queue(),?^{
NSLog(@"updateUi");
});
dispatch_release(group);
