警告：尝试在其 ViewController 上呈现 ViewController 不在视图层次结构中（3D Touch）

Question

基本上，我正在尝试在我的应用程序中实现主屏幕快速操作。当我点击其中一项快速操作时，出现错误：

Warning: Attempt to present theViewController on ViewController whose view is not in the window hierarchy!

我查看了其他一些具有相同问题的 Stack Over Flow 帖子，但解决方案对我不起作用。此外，在我的 applicationDidEnterBackground 方法中，我添加了 self.window?.rootViewController?.dismissViewControllerAnimated(true, completion: nil).

以下是我在 App Delegate 中包含的一些相关 3D Touch 方法：

func application(application: UIApplication, performActionForShortcutItem shortcutItem: UIApplicationShortcutItem, completionHandler: (Bool) -> Void) {
    let handledShortcutItem = self.handleShortuctItem(shortcutItem)
    completionHandler(handledShortcutItem)
}

此外，我还有这些辅助方法：

    enum ShortcutIdentifier: String {
    case First
    case Second

    init?(fullType: String) {
        guard let last = fullType.componentsSeparatedByString(".").last else { return nil }
        self.init(rawValue: last)
    }
    var type: String {
        return NSBundle.mainBundle().bundleIdentifier! + ".\(self.rawValue)"
    }
}

func handleShortuctItem(shortcutItem: UIApplicationShortcutItem) -> Bool {
    var handled = false

    guard ShortcutIdentifier(fullType: shortcutItem.type) != nil else { return false }
    guard let shortcutType = shortcutItem.type as String? else { return false }

    switch(shortcutType) {
    case ShortcutIdentifier.First.type:
        handled = true
        let navVC = mainStoryboard.instantiateViewControllerWithIdentifier("firstViewController") as! FirstViewController
        self.window?.rootViewController?.presentViewController(navVC, animated: true, completion: nil)
        break
    case ShortcutIdentifier.Second.type:
        handled = true
        let navVC = mainStoryboard.instantiateViewControllerWithIdentifier("secondViewController") as! SecondViewController
        self.window?.rootViewController?.presentViewController(navVC, animated: true, completion: nil)
        break
    default:
        break
    }


    return handled
}

Answer 1

一种无意识的解决方案是在您的 presentViewController 调用周围设置延迟（delay 定义为：dispatch_after - GCD in swift?）：

switch(shortcutType) {
case ShortcutIdentifier.First.type:
    handled = true
    let navVC = mainStoryboard.instantiateViewControllerWithIdentifier("firstViewController") as! FirstViewController
    delay(0.3) {
        self.window?.rootViewController?.presentViewController(navVC, animated: true, completion: nil)
    }
    break
case ShortcutIdentifier.Second.type:
    handled = true
    let navVC = mainStoryboard.instantiateViewControllerWithIdentifier("secondViewController") as! SecondViewController
    delay(0.3) {
        self.window?.rootViewController?.presentViewController(navVC, animated: true, completion: nil)
    }
    break
default:
    break
}

想法是让界面有时间在尝试进行演示之前完成显示。

警告：尝试在其 ViewController 上呈现 ViewController 不在视图层次结构中（3D Touch）

Warning: Attempt to Present ViewController on whose ViewController isn't in the view hierarchy (3D Touch)

swift

appdelegate

3dtouch