带有Swift的AppDelegate中的UINavigationBar setBackgroundImage [英] UINavigationBar setBackgroundImage in AppDelegate with Swift

问题描述

我正在尝试在Swift的App Delegate中将背景图像全局设置为导航栏. 我可以像这样在单个View Controller上运行它:

I am trying to set a background image to the navigation bar globally in the App Delegate in Swift. I can get it to work on an individual View Controller like this:

var topBar: UINavigationBar!

topBar.setBackgroundImage(UIImage(named: "navbar"), forBarMetrics:
.Default)

但是，当我尝试将以下内容添加到App Delegate时，它崩溃并发生未捕获的异常:

But when I try and add the following to the App Delegate, it crashes with an uncaught exception:

UINavigationBar.appearance().setBackgroundImage(UIImage(named:
"navbar"), forBarMetrics: .Default)

推荐答案

好，我删除了导航栏，并在情节提要中添加了新的……现在它仅适用于App Delegate代码.我想这只是Xcode 6/Swift的越野车.

OK, I deleted the navigation bars and added new ones in the storyboard... now it works with just the App Delegate code. It's just Xcode 6/Swift being buggy, I guess.

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