UINavigationController 导航控制器 常用总结
//导航控制器跳转到下一页
[self.navigationController pushViewController:second animated:YES];
//返回上一页
[self.navigationController popViewControllerAnimated:YES];
//返回首页:popToRootViewControllerAnimated 除第一个页面外,其他的页面全部出栈
[self.navigationController popToRootViewControllerAnimated:YES];
//self.navigationController.viewControllers 找到push过去的页面,并放到数组里面
NSArray *viewController = self.navigationController.viewControllers;
[self.navigationController popToViewController:viewController[2] animated:YES];