SwiftUI 2.0: export group of images with .fileExporter modifier

Question

Created Feb ’21

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Goal: export a group of images in SwiftUI

What I did: I am using the .fileExporter modifier, with the FileDocument struct. Also open to other approach, like . fileMover modifier for example.

Problem: When setting the FileDocument for multiple images struct I am getting am error on func fileWrapper (check code bellow).

Question: How can I export multiple images in SwiftUI (could be any method)?

Code Block  //file exporter
    .fileExporter(isPresented: $exportFile, document: ImageDocument(
                    
                    
                    image: UIImage(data: product.cover ?? Data())!,
                    image2:  UIImage(data: product.cover2 ?? Data())!)
                  
                  ,
           
contentType: .jpeg, onCompletion: { (result) in
            if case .success = result {
                
                print("Success")
            } else {
                print("Failure")
            }
        })

Code Block //export group of images
struct ImageDocument: FileDocument {
    
    static var readableContentTypes: [UTType] { [.jpeg] }
    var image: UIImage
    var image2: UIImage
    init(
        image: UIImage?,
        image2: UIImage?
    ) {
        
        self.image = image ?? UIImage()
        self.image2 = image2 ?? UIImage()
    }
    
    init(configuration: ReadConfiguration) throws {
        guard let data = configuration.file.regularFileContents,
              let image = UIImage(data: data),
              let image2 = UIImage(data: data)
        else {
            throw CocoaError(.fileReadCorruptFile)
        }
        self.image = image
        self.image2 = image2
    }
    func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
        return FileWrapper(regularFileWithContents:
                            image.jpegData(compressionQuality: 0.80)!,
                            image2.jpegData(compressionQuality: 0.80)!//<----- getting an "extra argument error here
                            )
    }
    
}

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Answer 1

the_max OP

Feb ’21

Hi! I posted an answer to this in your Stack Overflow question, duplicating here in case someone finds this before SO:

You need to use fileExporter with documents argument instead of document, which takes in a Collection

macOS example:

Code Block swiftimport SwiftUI
import UniformTypeIdentifiers
struct ImageDocument: FileDocument {
  static var readableContentTypes: [UTType] { [.jpeg, .png, .tiff] }
  var image: NSImage
  init(image: NSImage?) {
    self.image = image ?? NSImage()
  }
  init(configuration: ReadConfiguration) throws {
    guard let data = configuration.file.regularFileContents,
          let image = NSImage(data: data)
    else {
      throw CocoaError(.fileReadCorruptFile)
    }
    self.image = image
  }
  func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
    /* You can replace tiff representation with what you want to export */
    return FileWrapper(regularFileWithContents: image.tiffRepresentation!)
  }
}
@main
struct FocalApp: App {
  @StateObject var appContext = AppContext()
  var body: some Scene {
    WindowGroup {
      MainView()
        .environmentObject(self.appContext)
        .fileExporter(
          isPresented: $appContext.fileSaveDialogShown,
          documents: [
            ImageDocument(image: NSImage(named: "testimage1")),
            ImageDocument(image: NSImage(named: "testimage2"))
          ],
          contentType: .tiff /* Match this to your representation in ImageDocument */
        ) { url in
          print("Saved to", url) /* [URL] */
        }
    }
  }
}

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