//请求数据    dispatch_async(dispatch_get_global_queue(0, 0), ^{        _dataArray=[NSMutableArray array];        NSString *urlStr=[NSString stringWithFormat:MAINMENU_URL,kHost_And_Port];        NSLog(@"%@", urlStr);        NSData *data=[NSData dataWithContentsOfURL:[NSURL URLWithString:urlStr]];        if (data) {            NSDictionary *rootdict=[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];            for (NSDictionary *dic in rootdict[@"data"]) {                [_dataArray addObject:dic[@"imagePathLandscape"]];            }            //回到主线程  刷新数据            dispatch_async(dispatch_get_main_queue(), ^{                [_tableView reloadData];            });        }    });