为什么swift5不支持导入文件的类型?

Why don't support the type of imported file in swift5?

我是 iOS 的开发者。我目前正在制作一个加密钱包。加载 keystore 文件类型时不支持的问题。我将 Info.list 文件中的数据类型保存为 public.data 以扩大范围。我可以选择一个文件,但我在加载它时没有传递它。有什么问题吗?

DocumentBrowserViewController.swift

class DocumentBrowserViewController : UIDocumentBrowserViewController, UIDocumentBrowserViewControllerDelegate {
...
    func presentDocument(at documentURL: URL) throws {


        // Start accessing a security-scoped resource.
        guard documentURL.startAccessingSecurityScopedResource() else {
            throw IXError.fileAcessFailed
        }


        let storyBoard = UIStoryboard(name: "Main", bundle: nil)
        let documentViewController = storyBoard.instantiateViewController(withIdentifier: "MainViewController") as! MainViewController

        documentViewController.document = Document(fileURL: documentURL)


        present(documentViewController, animated: true, completion: nil)
        Log.Debug(documentURL)
         defer { documentURL.stopAccessingSecurityScopedResource() }
    }

Document.swift

import UIKit


class Document: UIDocument {


    var fileData: Data?

    var filesText: ****.Wallet?

    override func contents(forType typeName: String) throws -> Any {


        Log.Debug("**********************************************************")
        if typeName == "public.data" {

            if let content = filesText {


                let data = content
                return data

            } else {
                return Data()
            }

        } else {
            Log.Debug("**********************************************************")
            return Data()
        }

    } // end func contents

    override func load(fromContents contents: Any, ofType typeName: String?) throws {


        if let fileType = typeName {


            if fileType == "public.png" || fileType == "public.jpeg" { // .jpg not recognized


                if let fileContents = contents as? Data {

                    fileData = fileContents

                }


            } else if fileType == "public.data" {


                if let fileContents = contents as? ***.Keystore {

//                    filesText = String(data: fileContents, encoding: .utf8)
                    filesText = ***.Wallet.init(keystore: fileContents)
                }

            } else {
                Log.Debug("**********************************************************")
                print("File type unsupported.") // Keystore file here
            }

        } // end if let fileType = typeName

    } // end func load

    public var state: String {

        switch documentState {

        case .normal:
            return "Normal"
        case .closed:
            return "Closed"
        case .inConflict:
            return "Conflict"
        case .savingError:
            return "Save Error"
        case .editingDisabled:
            return "Editing Disabled"
        case .progressAvailable:
            return "Progress Available"

        default:
            return "Unknown"

        }

    } // end public var state

} // end class Document

MainController.swift

        document?.open(completionHandler: { (success) in

            if success {
                if self.document?.fileType == "public.png" || self.document?.fileType == "public.jpeg" {


//                    self.imageView.image = UIImage(data: (self.document?.fileData)!)
                    Log.Debug("#################################################")
                    print("\(String(describing: self.document?.fileData))")
                    Log.Debug("#################################################")

                    // #4.5 - If the UIDocument reports that it is a text file...
                } else if self.document?.fileType == "public.data" {


//                    self.textView.text = self.document?.filesText!
                    Log.Debug("**********************************************************")
                    print("\(String(describing: self.document?.filesText))")
                    Log.Debug("**********************************************************")

                }
                Log.Debug("**********************************************************")
                print("\(String(describing: self.document?.fileURL.lastPathComponent))")
                Log.Debug("**********************************************************")
                print("Document state: \((self.document?.state)!)")
                Log.Debug("**********************************************************")

            } else {
                // Make sure to handle the failed import appropriately, e.g., by presenting an error message to the user.
            }

        })

Info.list

文件网址

file:///Users/******/Library/Developer/CoreSimulator/Devices/15169C47-DC68-4B14-B8E8-F75E4108AB7A/data/Containers/Data/Application/499E0805-A3AE-4312-B8B4-55236CFC7BD8/Documents/***/******

内容:

Document.swift load(fromContents:ofType:) [Line:69] <7b226164 64726573 73223a22 64616361 66333634 35393939 36323366 32383535 65636262 36393661 ... >

类型名称:

load(fromContents:ofType:) [Line:71] Optional("dyn.ah62d4rv4ge8xeqbwtk0w43dbqru0qq30gu4xwsm3g23dg3vwha4xn3pdqmvdqsm0qe6xgqbuqu6ds2mwqmw0q2v2he")

此文件不符合这两个条件中的任何一个。我的文件必须通过“public.data”条件。我做错了什么?

************************************************ * 编辑 *************************

Info.list

<key>CFBundleDocumentTypes</key>
<array>
    <dict>
        <key>CFBundleTypeIconFiles</key>
        <array/>
        <key>CFBundleTypeName</key>
        <string>images</string>
        <key>CFBundleTypeRole</key>
        <string>Viewer</string>
        <key>LSHandlerRank</key>
        <string>Alternate</string>
        <key>LSItemContentTypes</key>
        <array>
            <string>public.image</string>
        </array>
    </dict>
    <dict>
        <key>CFBundleTypeIconFiles</key>
        <array/>
        <key>CFBundleTypeName</key>
        <string>data</string>
        <key>LSHandlerRank</key>
        <string>Alternate</string>
        <key>LSItemContentTypes</key>
        <array>
            <string>public.data</string>
        </array>
    </dict>
</array>

针对 typeName 的硬编码相等性检查是你出错的地方。

如您所见,您的文件没有文件扩展名。文件扩展名是系统用于确定系统上特定文件的通用类型标识符 (UTI) 的唯一真实来源。

没有文件扩展名,我认为系统会将整个文件名视为扩展名。鉴于没有列出使用与您的文件名匹配的扩展名的 UTI (0ec6dcc292ec87067774805cb63a4c4694a35e33),系统会在遇到没有注册 UTI 的扩展名时执行它总是做的事情:它会创建一个动态 UTI。

动态 UTI 以 "dyn." 开头,后面跟着一些看似随意的字符,实际上是对未注册 UTI 的已知元数据(文件扩展名、MIME 类型、OSType、PastboardTypes 等)的编码。

你的错误源于对 typeName:

的精确匹配
if typeName == "public.data" {
    // ...
}

鉴于 typeName 的值为 dyn.ah62d4rv4ge8xeqbwtk0w43dbqru0qq30gu4xwsm3g23dg3vwha4xn3pdqmvdqsm0qe6xgqbuqu6ds2mwqmw0q2v2he,这显然会失败。

相反,您应该检查一致性:

import Foundation
import CoreServices

// A helper function to hide away the CFString bridging cruft
func uti(_ uti: String, conformsTo candidateParent: String) -> Bool {
    return UTTypeConformsTo(uti as CFString, candidateParent as CFString)
}

// ...

if uti(typeName, conformsTo: "public.data") {
    // ...
}