用init创建的的控制器的视图会从下面的方法加载
loadview
是否指定xib名称
CZLoginView.xib
CZLoginViewController.xib
是否指定storyboard
//在main.storyboard加载控制器
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
XJViewController *loginVc = [storyboard instantiateViewControllerWithIdentifier:@"login"];
// CZLoginViewController *loginVc = [storyboard instantiateInitialViewController]; //storyboard中箭头所指的方