的UIWindow？没有名为bounds的成员 [英] UIWindow? does not have member named bounds

问题描述

我正在尝试更新PKHUD（ https://github.com/pkluz/PKHUD ）使用Xcode 6 beta 5几乎可以使用除了一个小细节：

I'm trying to update PKHUD (https://github.com/pkluz/PKHUD) to work with Xcode 6 beta 5 and am almost through except for one tiny detail:

internal class Window: UIWindow {
    required internal init(coder aDecoder: NSCoder!) {
        super.init(coder: aDecoder)
    }

    internal let frameView: FrameView
    internal init(frameView: FrameView = FrameView()) {
        self.frameView = frameView

        // this is the line that bombs
        super.init(frame: UIApplication.sharedApplication().delegate.window!.bounds)

        rootViewController = WindowRootViewController()
        windowLevel = UIWindowLevelNormal + 1.0
        backgroundColor = UIColor.clearColor()

        addSubview(backgroundView)
        addSubview(frameView)
    }
    // more code here
}

Xc颂歌给我错误 UIWindow？没有名为'bounds'的成员。
我很确定这是一个与打字有关的微不足道的错误，但我几个小时都找不到答案。

Xcode gives me the error UIWindow? does not have a member named 'bounds'. I'm pretty sure this is a trivial mistake related to type-casting, but I've been unable to find the answer to this for a couple hours.

此外，此错误仅发生在Xcode 6 beta 5中，这意味着答案在于Apple最近更改的内容。

Also, this error occurs only in Xcode 6 beta 5, which means that the answer lies in something Apple changed recently.

非常感谢所有帮助。

推荐答案

UIApplicationDelegate中窗口属性的声明协议
从

The declaration of the window property in the UIApplicationDelegate protocol changed from

optional var window: UIWindow! { get set } // beta 4

到

optional var window: UIWindow? { get set } // beta 5

这意味着它是一个可选属性，产生一个可选的 UIWindow ：

which means that it is an optional property yielding an optional UIWindow:

println(UIApplication.sharedApplication().delegate.window)
// Optional(Optional(<UIWindow: 0x7f9a71717fd0; frame = (0 0; 320 568); ... >))

所以你必须打开它两次：

So you have to unwrap it twice:

let bounds = UIApplication.sharedApplication().delegate.window!!.bounds

或者，如果你想检查是否有可能应用程序委托有
无窗口属性，或者设置为 nil ：

or, if you want to check for the possibility that the application delegate has no window property, or it is set to nil:

if let bounds = UIApplication.sharedApplication().delegate.window??.bounds {

} else {
    // report error
}

更新：使用Xcode 6.3，委托属性现在也是
被定义为可选，所以代码现在是

Update: With Xcode 6.3, the delegate property is now also defined as an optional, so the code would now be

let bounds = UIApplication.sharedApplication().delegate!.window!!.bounds

或

if let bounds = UIApplication.sharedApplication().delegate?.window??.bounds {

} else {
    // report error
}

另见为什么主窗口是输入double optional？以获得更多解决方案。

See also Why is main window of type double optional? for more solutions.

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