如何在Swift中调用`setViewControllers:animated:`？

Question

当用户点击按钮时,我尝试在导航控制器中更改我的视图控制器,因此我声明了以下代码:

if standingsViewController == nil {
   standingsViewController = StandingsViewController()
   splitViewController!.delegate = standingsViewController
}
var vc = splitViewController!.viewControllers[1] as UINavigationController
vc.setViewControllers([standingsViewController], animated: true)

但是,这会导致错误:fatal error: attempt to bridge an implicitly unwrapped optional containing nil在最后一行.

UINavigationController的setViewControllers: animated:方法是在Swift中正确定义的,那么如何解决问题呢？

当我尝试将其更改为您的信息时[standingsViewController]!,它甚至没有通过编译,因为[AnyObject] is not identical to [AnyObject]!.

我在Swift中使用Xcode 6.1 beta.

Answer 1

看起来你忘了打开包装:

vc.setViewControllers([standingsViewController!], animated: true)

代替

vc.setViewControllers([standingsViewController], animated: true)