设置ViewController 数据源无法改变view

病情描述：

1. viewController创建的时候勾选了xib，然后在显示的时候调用了如下语句：

        MTDetailDealViewController *detailController = [[MTDetailDealViewController alloc]init];
        detailController.deal = [self.deals objectAtIndex:indexPath.item];
        [self presentViewController:detailController animated:YES completion:nil];
   

2. 发现界面根本没有按照数据源发生改变

病情原因：

1. 将viewController的几个生命周期关键方法进行打印，发现：
   
            2016-04-20 01:26:44.369 MTHD[6384:380078] -[MTDetailDealViewController initWithNibName:bundle:](114):
            2016-04-20 01:26:44.370 MTHD[6384:380078] -[MTDetailDealViewController init](99):
            2016-04-20 01:26:44.370 MTHD[6384:380078] -[MTDetailDealViewController setDeal:](50):
            2016-04-20 01:26:45.421 MTHD[6384:380078] -[MTDetailDealViewController loadView](95):
   

2. 联想起上篇知识总结
   
   iOS viewController 和 view 的创建消失生命周期总结的第4点

改正如下：

         MTDetailDealViewController *detailController = [[MTDetailDealViewController alloc]init];
        //必须得先调用view,否则下面的句子将会无效
        [detailController loadView];
        detailController.deal = [self.deals objectAtIndex:indexPath.item];
        [self presentViewController:detailController animated:YES completion:nil];

再次打印发现：

            2016-04-20 01:29:28.728 MTHD[6452:382311] -[MTDetailDealViewController initWithNibName:bundle:](114):
            2016-04-20 01:29:28.729 MTHD[6452:382311] -[MTDetailDealViewController init](99):
            2016-04-20 01:29:28.983 MTHD[6452:382311] -[MTDetailDealViewController loadView](95):
            2016-04-20 01:29:28.983 MTHD[6452:382311] -[MTDetailDealViewController setDeal:](50):