第一种
详细可看此博文:http://blog.youkuaiyun.com/davidsph/article/details/8001247
[[NSBundle mainBundle] loadNibNamed:@"Empty" owner:self options:nil];
取返回的NSArray中 第一个
第二种
Nib *nib = [UINib nibWithNibName:@"Empty" bundle:[NSBundle mainBundle]];
[[nib instantiateWithOwner:self options:nil] firstObject];
第三种
在StoryBoard中
UIViewcontroller *login = [self.storyboard instantiateViewControllerWithIdentifier:@"Empty"];
详细可看此博文:http://blog.youkuaiyun.com/davidsph/article/details/8001247