问如何在iOS上启用文件和文件夹权限

EN

import SwiftUI
import UniformTypeIdentifiers
import Alamofire

struct ContentView: View {
    @AppStorage("bookmarkData") var downloadsBookmark: Data?
    
    @State private var showFileImporter = false
    
    var body: some View {
        VStack {
            Button("Set downloads directory") {
                showFileImporter.toggle()
            }
            
            Button("Save to downloads directory") {
                Task {
                    do {
                        let destination: DownloadRequest.Destination = { _, response in
                            // Save to a temp directory in app documents
                            let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0].appendingPathComponent("Downloads")
                            let suggestedName = response.suggestedFilename ?? "unknown"

                            let fileURL = documentsURL.appendingPathComponent(suggestedName)

                            return (fileURL, [.removePreviousFile, .createIntermediateDirectories])
                        }

                        let tempUrl = try await AF.download(URL(string: "https://i.imgur.com/zaVQDFJ.png")!, to: destination).serializingDownloadedFileURL().value
                        
                        // Get the bookmark data from the AppStorage call
                        guard let bookmarkData = downloadsBookmark else {
                            return
                        }
                        var isStale = false
                        let downloadsUrl = try URL(resolvingBookmarkData: bookmarkData, bookmarkDataIsStale: &isStale)
                        
                        guard !isStale else {
                            // Log that the bookmark is stale
                            
                            return
                        }
                        
                        // Securely access the URL from the bookmark data
                        guard downloadsUrl.startAccessingSecurityScopedResource() else {
                            print("Can't access security scoped resource")
                            
                            return
                        }
                        
                        // We have to stop accessing the resource no matter what
                        defer { downloadsUrl.stopAccessingSecurityScopedResource() }
                        
                        do {
                            try FileManager.default.moveItem(at: tempUrl, to: downloadsUrl.appendingPathComponent(tempUrl.lastPathComponent))
                        } catch {
                            print("Move error: \(error)")
                        }
                    } catch {
                        print("Downloading error!: \(error)")
                    }
                }
            }
        }
        .fileImporter(isPresented: $showFileImporter, allowedContentTypes: [UTType.folder]) { result in
            switch result {
            case .success(let url):
                // Securely access the URL to save a bookmark
                guard url.startAccessingSecurityScopedResource() else {
                    // Handle the failure here.
                    return
                }
                
                // We have to stop accessing the resource no matter what
                defer { url.stopAccessingSecurityScopedResource() }
                
                do {
                    // Make sure the bookmark is minimal!
                    downloadsBookmark = try url.bookmarkData(options: .minimalBookmark, includingResourceValuesForKeys: nil, relativeTo: nil)
                } catch {
                    print("Bookmark error \(error)")
                }
            case .failure(let error):
                print("Importer error: \(error)")
            }
        }
    }
}