xcode - SwiftUI:.fileExporter 仅导出 1 个文档

Question

平台和版本 iOS Xcode 版本 12.4 (12D4e)

目标：使用 SwiftUI .fileExporter 修饰符导出多个图像。

问题：在使用 NS Image 的 MacOS 上，所有图像都被导出。在使用 UIImage 的 iOS（iPad、Catalyst 和 iPhone）上，仅导出 1 个图像

重现步骤

iOS 代码：

import SwiftUI

class AppContext: ObservableObject {
@Published var fileSaveDialogShown = false
}

@main
struct ExportApp: App {
@StateObject var appContext = AppContext()

var body: some Scene {
WindowGroup {
ContentView()
.environmentObject(self.appContext)
.fileExporter(
isPresented: $appContext.fileSaveDialogShown,
documents: [
ImageDocument(image: UIImage(named: "1")),
ImageDocument(image: UIImage(named: "2"))
],
contentType: .png // Match this to your representation in ImageDocument
) { url in
print("Saved to", url) // [URL]
}
}
}
}

import SwiftUI
import UniformTypeIdentifiers

struct ImageDocument: FileDocument {
static var readableContentTypes: [UTType] { [.jpeg, .png, .tiff] }

var image: UIImage

init(image: UIImage?) {
self.image = image ?? UIImage()
}

init(configuration: ReadConfiguration) throws {
guard let data = configuration.file.regularFileContents,
let image = UIImage(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.pngData()!)
}
}


struct ContentView: View {

@EnvironmentObject var appContext: AppContext

var body: some View {
VStack {
Button(action: {
appContext.fileSaveDialogShown.toggle()
}, label: {
Text("Button")
})
}
.frame(width: 200, height: 200)
}
}

MacOS code:


import SwiftUI

class AppContext: ObservableObject {
@Published var fileSaveDialogShown = false
}

@main
struct FocalApp: App {
@StateObject var appContext = AppContext()

var body: some Scene {
WindowGroup {
ContentView()
.environmentObject(self.appContext)
.fileExporter(
isPresented: $appContext.fileSaveDialogShown,
documents: [
ImageDocument(image: NSImage(named: "1")),
ImageDocument(image: NSImage(named: "2"))
],
contentType: .jpeg // Match this to your representation in ImageDocument
) { url in
print("Saved to", url) // [URL]
}
}
}
}



import 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!)
}
}


struct ContentView: View {

@EnvironmentObject var appContext: AppContext

var body: some View {
VStack {
Button(action: {
appContext.fileSaveDialogShown.toggle()
}, label: {
Text("Button")
})
}
.frame(width: 200, height: 200)
}
} 

标签： xcodeswiftui

Answer 1

您似乎需要为每个导出的文件提供唯一的名称。如果没有明确定义名称，两个图像都将被命名为“导出的 PNG 图像”，因此第一个将被覆盖。

这对我有用：

import SwiftUI

class AppContext: ObservableObject {
    @Published var fileSaveDialogShown = false
}

@main
struct ExportApp: App {
    @StateObject var appContext = AppContext()
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(self.appContext)
                .fileExporter(
                    isPresented: $appContext.fileSaveDialogShown,
                    documents: [
                        ImageDocument(image: UIImage(named: "1"), name: "1"),
                        ImageDocument(image: UIImage(named: "2"), name: "2")
                    ],
                    contentType: .png // Match this to your representation in ImageDocument
                ) { url in
                    print("Saved to", url) // [URL]
                }
        }
    }
}


import SwiftUI
import UniformTypeIdentifiers

struct ImageDocument: FileDocument {
    static var readableContentTypes: [UTType] { [.jpeg, .png, .tiff] }
    
    var image: UIImage
    var name: String
    
    init(image: UIImage?, name: String) {
        self.image = image ?? UIImage()
        self.name = name
    }
    
    init(configuration: ReadConfiguration) throws {
        guard let data = configuration.file.regularFileContents,
              let image = UIImage(data: data)
        else {
            throw CocoaError(.fileReadCorruptFile)
        }
        self.image = image
        self.name = configuration.file.filename ?? "image"
    }
    
    func fileWrapper(configuration: WriteConfiguration) throws -> FileWrapper {
        // You can replace tiff representation with what you want to export
        let fileWrapper = FileWrapper(regularFileWithContents: image.pngData()!)
        fileWrapper.filename = self.name
        return fileWrapper
    }
}


struct ContentView: View {
    
    @EnvironmentObject var appContext: AppContext
    
    var body: some View {
        VStack {
            Button(action: {
                appContext.fileSaveDialogShown.toggle()
            }, label: {
                Text("Button")
            })
        }
        .frame(width: 200, height: 200)
    }
}