iOS PDFKit不会写

Question

import UIKit
import PDFKit

class ViewController: UIViewController {

    @IBOutlet weak var pdfView: PDFView!

    lazy var pdfDoc:PDFDocument? = {
        guard let path = Bundle.main.path(forResource: "6368", ofType: "pdf") else {return nil}
        let url = URL(fileURLWithPath: path)
        return PDFDocument(url: url)
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.setupPDFView()
        self.save()
    }

    func setupPDFView() {
        //Setup and put pdf on view
        pdfView.autoScales = true
        pdfView.displayMode = .singlePageContinuous
        pdfView.displayDirection = .horizontal
        pdfView.document = pdfDoc

        self.add(annotation: self.circleAnnotation(), to: 0)
    }

    func add(annotation: PDFAnnotation, to page:Int){
        self.pdfDoc?.page(at: page)?.addAnnotation(annotation)
    }

    func circleAnnotation()->PDFAnnotation {
        let bounds = CGRect(x: 20.0, y: 20.0, width:200.0, height: 200.0)
        let annotation = PDFAnnotation(bounds: bounds, forType: .circle, withProperties: nil)
        annotation.interiorColor = UIColor.black
        return annotation
    }

    func save() {
        //Save to file
        guard let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else {return}
        let data = pdfView.document?.dataRepresentation()
        do {
            if data != nil{try data!.write(to: url)}
        } 
        catch {
            print(error.localizedDescription)
        }
    }
}

这只是简单的 PDFKit 代码，应该在 pdf 的第一页上添加一个圆圈并将其保存到文档目录中。所有作品，除了保存。当我在 let data = .. 之后断点时。显示有数据，但是有两个错误:

1) 2018-12-18 05:10:28.887195-0500 PDFWriteTest[21577:1331197] [Unknown process name] Failed to load /System/Library/PrivateFrameworks/CorePDF.framework/Versions/A/CorePDF

• 不管我是否发现错误并打印，这个都会显示

2) The file “Documents” couldn’t be saved in the folder “D3E23B05-92...”.

• 这是从 error.localizedDescription 打印的内容

可以使用 PDFKit 解决这个问题(将 PDF 数据保存到文件)吗？

Answer 1

您不能将数据直接写入表示 Documents 文件夹的 URL，您必须指定(并附加)一个文件名。

func save(filename : String) {
    //Save to file
    guard let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first,
          let data = pdfView.document?.dataRepresentation() else {return}
    let fileURL = url.appendingPathComponent(filename)
    do {
        try data.write(to: fileURL)
    } catch {
        print(error.localizedDescription)
    }
}