ios - 在 iPad 上呈现 View Controller 只允许 .Popover

Question

我有一个 iPhone 应用程序，我正试图使其通用。我有这段代码:

let documentMenu = UIDocumentMenuViewController(documentTypes: [kUTTypeContent as String], inMode: .Import)
documentMenu.modalPresentationStyle = .FormSheet
documentMenu.delegate = self
self.presentationContext.presentViewController(documentMenu, animated: true, completion: nil)

self.presentationContext 只是传递给类的 View Controller 。

每次执行这段代码，都会出现这个错误:

Your application has presented a UIDocumentMenuViewController (). In its current trait environment, the modalPresentationStyle of a UIDocumentMenuViewController with this style is UIModalPresentationPopover. You must provide location information for this popover through the view controller's popoverPresentationController. You must provide either a sourceView and sourceRect or a barButtonItem. If this information is not known when you present the view controller, you may provide it in the UIPopoverPresentationControllerDelegate method -prepareForPopoverPresentation.

我不确定发生了什么。我什至尝试设置 sourceView 和 sourceRect，这确实会阻止错误，但是，它将 DocumentMenuViewController 粘贴到弹出窗口中，我不要什么那个。我需要将其模态显示在屏幕中央。感谢您的帮助。

Answer 1

以下代码运行良好

let importMenu = UIDocumentMenuViewController(documentTypes: [String(kUTTypePDF)], in: .import)

    importMenu.popoverPresentationController?.sourceView = self.view // so that iPads won't crash

    importMenu.delegate = self
    importMenu.modalPresentationStyle = .formSheet
    self.present(importMenu, animated: true, completion: nil)