页面的跳转

 页面的跳转有3种方式:

1.在window上创建2个UIView  ,将原来的View从window上移除,将另一个View添加到window上

2.模态弹出或者模态消除:模态弹出一个视图控制器,弹出的新控制器view会覆盖本身的view

RegistVC *vc = [[RegistVC alloc]init];

[self presentViewController: vc animated :YES completion:nil];

     //模态消失

    [self dismissViewControllerAnimated:YES completion:nil];

3.创建根视图控制器  UINavigationController

MainVC *vc = [[MainVC alloc]init];

UINavigationController *nvc = [[UINavigationController alloc]initWithRootViewController:vc]

UIWindow *window = [[[UIApplication sharedApplication]delegate]window];

window.rootViewController = nvc;