为什么我看不到我的新UIWindow?

时间:2017-05-27 18:34:43

标签: swift3 uiwindow

场景:创建并显示叠加(辅助)UIWindow。
相关讨论: How do I toggle between UIWindows?

代码:

fileprivate func displayOverLay() {
    let myWindow = {() -> UIWindow in
        let cWindow = UIWindow(frame: CGRect(x: 10, y: 200, width: 300, height: 300))
        cWindow.backgroundColor = UIColor.gray.withAlphaComponent(0.5)
        cWindow.tag = 100
        return cWindow
    }()
    myWindow.makeKeyAndVisible()
    myWindow.windowLevel = UIWindowLevelAlert
    let storyboard = UIStoryboard(name: "Hamburger", bundle: nil)
    let vc = storyboard.instantiateInitialViewController()
    myWindow.rootViewController = vc
    return
}

这是共享的UIApplication窗口状态:

(lldb) po UIApplication.shared.windows 
▿ 2 elements
  - 0 : <UIWindow: 0x7fcffc804860; frame = (0 0; 375 667); autoresize = W+H; gestureRecognizers = <NSArray: 0x600000051280>; layer = <UIWindowLayer: 0x60000003e840>>
  - 1 : <UIWindow: 0x7fcff9407240; frame = (10 200; 300 300); tag = 100; gestureRecognizers = <NSArray: 0x608000052810>; layer = <UIWindowLayer: 0x608000220420>>


(lldb) po UIApplication.shared.keyWindow!
<UIWindow: 0x7fcff9407240; frame = (10 200; 300 300); tag = 100; gestureRecognizers = <NSArray: 0x608000052810>; layer = <UIWindowLayer: 0x608000220420>>

结果如下:没有灰色窗口

enter image description here

<小时/> 重要提示:如果我在displayOverLay()的末尾刹车并做了一个“我的窗口”,然后继续,我会看到显示。

enter image description here

所以出现 我错过了某种事件以显示UIWindow。
强制新UIWindow w /内容实际显示需要什么?

1 个答案:

答案 0 :(得分:1)

您需要保留对创建窗口的引用,否则ARC将在您从函数返回后处理窗口。

例如,您可以从函数中返回新创建的窗口,并将其存储在您调用该函数的类的属性中。