Swift CSVImporter 无法读取 CSV 文件

Question

我正在使用 CSVImporter pod 来解析从 iCloud Drive 上传的 CSV 文件，每行解析的目的都是要上传到我的数据库。

当importFile() 被执行时，它会打印路径，但随后会打印"The CSV file couldn't be read."

Q1：我做错了什么？

import UIKit
import MobileCoreServices
import CSVImporter

class importBatchVC: UIViewController,UIDocumentPickerDelegate,UINavigationControllerDelegate {
    var path=""
    var docURL = URL(string: "")

    @IBAction func chooseDoc(_ sender: Any) {
        let importMenu = UIDocumentPickerViewController(documentTypes: [String(kUTTypeContent),String(kUTTypePlainText)], in: .import)
        importMenu.delegate = self
        importMenu.modalPresentationStyle = .formSheet
        self.present(importMenu, animated: true, completion: nil
    }

    @IBAction func importFile(_ sender: Any) {
        if docURL==nil {
            let alert = UIAlertController(title: "Error", message: "Please select a spreadsheet.", preferredStyle: UIAlertControllerStyle.alert)
            alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: nil))
            self.present(alert, animated: true, completion: nil)
        } else {
            do {
                self.path = String(describing:docURL)
                print(path)

                let importer = CSVImporter<[String]>(path: path)
                importer.startImportingRecords { $0 }.onFail {
                        print("The CSV file couldn't be read.")
                    }.onProgress { importedDataLinesCount in
                        print("\(importedDataLinesCount) lines were already imported.")
                    }.onFinish { importedRecords in
                        print("Did finish import with \(importedRecords.count) records.")
                }
            }
        }
    }

    @IBAction func cancel(_ sender: Any) {
        self.dismiss(animated: true, completion: nil)
    }

    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) {
        print("The Url is : \(String(describing: url))")
        let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        do {
            try FileManager.default.moveItem(at: url.standardizedFileURL, to: documentDirectory.appendingPathComponent(url.lastPathComponent))

            self.docURL = documentDirectory.appendingPathComponent(url.lastPathComponent)
            print("now check this: \(docURL!)")
        } catch {
            print(error)
        }
    }

    func documentMenu(_ documentMenu: UIDocumentPickerViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) {
        documentPicker.delegate = self
        present(documentPicker, animated: true, completion: nil)
    }
}

注意：这是作为“重复”关闭的转发问题，上面的代码是建议的实现。

我最初和首选的实现是通过documentPicker 获取 iCloud 驱动器文件的链接并即时解析/上传到数据库，但我遇到了与现在相同的错误：“CSV 文件无法”不能读。”

Leo Dabus 提供的解释是： "UIDocumentPickerModeImport The URL refers to a copy of the selected document. This document is a temporary file. It remains available only until your application terminates. To keep a permanent copy, you must move this file to a permanent location inside your sandbox."

Q2: 考虑到我不需要保留一个永久文件-只需要保留它直到它被解析然后它就会在我的数据库中，为什么我需要将它导入到documentDirectory，有没有我可以通过从 documentPicker 获得的链接来解析它吗？

我的初始实现代码：

 import UIKit
 import MobileCoreServices
 import CSVImporter

class importBatchVC: UIViewController,UIDocumentPickerDelegate,UINavigationControllerDelegate {
 var path=""
 var docURL = URL(string: "")

@IBAction func chooseDoc(_ sender: Any) {
    let importMenu = UIDocumentPickerViewController(documentTypes: [String(kUTTypeContent),String(kUTTypePlainText)], in: .import)
    importMenu.delegate = self
    importMenu.modalPresentationStyle = .formSheet
    self.present(importMenu, animated: true, completion: nil)
}

  @IBAction func importFile(_ sender: Any) {
    if docURL==nil {
        let alert = UIAlertController(title: "Error", message: "Please select a spreadsheet.", preferredStyle: UIAlertControllerStyle.alert)
        alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: nil))
        self.present(alert, animated: true, completion: nil)
    }

    else{
        do {
            self.path = docURL!.path
            print(path)

            let importer = CSVImporter<[String]>(path: path)
            importer.startImportingRecords { $0 }.onFinish { importedRecords in
                for record in importedRecords {
                    // record is of type [String] and contains all data in a line
                    print(record)
                }
            }

    }
}
}

@IBAction func cancel(_ sender: Any) {
    self.dismiss(animated: true, completion: nil)
}

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}

func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentAt url: URL) {
   docURL = url as URL
    print("The Url is : \(String(describing: url))")
}


func documentMenu(_ documentMenu: UIDocumentPickerViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) {
    documentPicker.delegate = self
    present(documentPicker, animated: true, completion: nil)
 }
}

Answer 1

第一季度：

我在尝试解析 docURL 的文件时看到的问题是以下行：

self.path = String(describing:docURL)

这不是将文件 URL 转换为路径的正确方法。正确的代码是：

self.path = docURL.path

第二季度：

当您在import 模式下使用UIDocumentPickerViewController 时，您在委托方法中给出的URL 仅在委托方法结束前有效。这就是您必须复制/移动所选文件的原因。

来自文档：

URL 是指所选文档的副本。这些文件是临时文件。它们仅在您的应用程序终止之前保持可用。要保留永久副本，请将这些文件移动到沙箱内的永久位置。

所以是的，您必须制作副本。但是你可以在解析完成后删除文件。