これ覚えといたほうがよい
1行で書きたいとき
dispatch_async(dispatch_get_main_queue(), ^{ [self.tableView reloadData]; }); dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0),^{ });
dispatch_async(dispatch_get_main_queue(), ^{ [self.tableView reloadData]; }); dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0),^{ });