iOS -Nav,tab跳转,返回

 TabBarViewController *tab =(TabBarViewController *) [UIApplication sharedApplication].windows.firstObject.rootViewController;    

    tab.selectedViewController=tab.viewControllers[1];

self.navigationController.tabBarController.selectedIndex=0;

[self.navigationController popViewControllerAnimated:YES];

[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:2] animated:YES];

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

[self dismissViewControllerAnimated:YES completion:nil];