iOS11dropInteractionperformDrop文件

我如何使用dropInteraction(_ interaction: UIDropInteraction, performDrop session: UIDropSession)接受其他类型的文件而不是图像？假设我从文件应用程序中拖动PDF或MP3.我如何接受此文件并获取数据？

我以为我可以使用NSURL.self,但这似乎只适用于从Safari och拖动的文本视图.

PDF(com.adobe.pdf UTI)实现的示例NSItemProviderReading可能是这样的:

class PDFDocument: NSObject, NSItemProviderReading {
    let data: Data?

    required init(pdfData: Data, typeIdentifier: String) {
        data = pdfData
    }

    static var readableTypeIdentifiersForItemProvider: [String] {
        return [kUTTypePDF as String]
    }

    static func object(withItemProviderData data: Data, typeIdentifier: String) throws -> Self {
        return self.init(pdfData: data, typeIdentifier: typeIdentifier)
    }
}

然后在您的委托中,您需要处理此PDFDocument:

extension YourClass: UIDropInteractionDelegate {
    func dropInteraction(_ interaction: UIDropInteraction, canHandle session: UIDropSession) -> Bool {
        return session.canLoadObjects(ofClass: PDFDocument.self))
    }

    .
    .
    .

    func dropInteraction(_ interaction: UIDropInteraction, performDrop session: UIDropSession) {
        session.loadObjects(ofClass: PDFDocument.self) { [unowned self] pdfItems in
            if let pdfs = pdfItems as? [PDFDocument], let pdf = pdfs.first {
                // Whatever you want to do with the pdf
            }
        }
    }
}