UIReferenceLibraryViewController 无法显示为弹出窗口（始终覆盖全屏）

Question

以下Swift 3 代码（贷记给Hacking With Swift) creates a UIAlertController and successfully presents it as a popup from a CGRect co-ordinate on iPad, via the UIPopoverPresentationController API:

func popUpToSelectTheLanguage(){
    let ac = UIAlertController(title: "Set expected language...", message: nil, preferredStyle: .actionSheet)
    ac.addAction(UIAlertAction(title: "English", style: .default, handler: { (action) in /* Action to take */ }))
    ac.addAction(UIAlertAction(title: "French", style: .default, handler: { (action) in /* Action to take */ }))
    ac.addAction(UIAlertAction(title: "Cancel", style: .cancel))

    let popover = ac.popoverPresentationController
    popover?.sourceView = view
    popover?.sourceRect = CGRect(x: 32, y: 32, width: 64, height: 64)
    present(ac, animated: true)
}

但是，当尝试将不同的 UIViewController 作为弹出窗口显示时，UIReferenceLibraryViewController（系统的 mono/bi-lingual 字典）会覆盖整个屏幕，而不是显示为弹出窗口。

func popUpTheDictionary(){
    let dic = UIReferenceLibraryViewController(term: "hi" as String)

    let popover = dic.popoverPresentationController
    popover?.sourceView = view
    popover?.sourceRect = CGRect(x: 32, y: 32, width: 64, height: 64)
    present(dic, animated: true)
}

这里有什么问题？是否需要进一步设置 UIReferenceLibraryViewController，或者它只是被锁定以防止作为弹出窗口显示？

我的目标是iOS 10.2，通用；为 iPad Pro（12.9 英寸）构建。

如果没有办法解决这个问题，我同样会接受任何提供通过另一个库将 UIReferenceLibraryViewController 呈现为弹出窗口所需的代码的答案（如果它在 iPhone 以及 iPad).

Answer 1

您需要将视图控制器的 modalPresentationStyle 设置为 .popover。

func popUpTheDictionary(){
    let dic = UIReferenceLibraryViewController(term: "hi" as String)
    dic.modalPresentationStyle = .popover // add this

    let popover = dic.popoverPresentationController
    popover?.sourceView = view
    popover?.sourceRect = CGRect(x: 32, y: 32, width: 64, height: 64)
    present(dic, animated: true)
}

UIAlertController 为您完成此操作，因为它始终是弹出窗口。

UIReferenceLibraryViewController 无法显示为弹出窗口（始终覆盖全屏）

UIReferenceLibraryViewController cannot be presented as popup (always covers full screen)

popup

uiviewcontroller

ipad

ios

swift