如何在Swift中获得Bool的相反值？ [英] How can I get the opposite value of a Bool in Swift?

问题描述

我的具体情况是我试图切换导航栏隐藏和显示。

My specific case is I am trying to toggle the nav bar hidden and showing.

    let navHidden = !self.navigationController?.navigationBarHidden
    self.navigationController?.setNavigationBarHidden(navHidden!, animated: true)

对我来说不像通常在Obj-C中那样。

Is not working for me like it normally would in Obj-C.

推荐答案

感叹号位于布尔值的错误一侧。你写它的方式表明布尔值可能是零。你想要！navHidden。

The exclamation point is on the wrong side of the boolean. The way you've written it would indicate that the boolean could be nil. You want !navHidden.

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