1.模態跳轉

這種方法也是目前網上最多的一種方法，具體代碼如下：

MessageViewController *VC = [[MessageViewController alloc] init];

UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:VC];

[self.window.rootViewController presentViewController:nav animated:YES completion:nil];

2.Push跳轉

有時候我們根據需求，需要使用push方法跳轉頁面，讓跳轉更舒服，

具體代碼如下：

UITabBarController *tab = (UITabBarController *)_window.rootViewController;

UINavigationController *nav = tab.viewControllers[tab.selectedIndex];

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

vc.hidesBottomBarWhenPushed = YES;

[nav pushViewController:vc animated:YES];