UIactivityController 不显示打印图像

Question

在 SwiftUI 应用程序中，我想使用共享表打印图像。在下面的代码表中打开空白总是显示没有图像。

import SwiftUI

struct ActivityViewController: UIViewControllerRepresentable {
    var activityItems: [Any]
    var applicationActivities: [UIActivity]? = nil

    func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>) -> UIActivityViewController {
        return UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
    }

    func updateUIViewController(_ uiViewController: UIActivityViewController, context: UIViewControllerRepresentableContext<ActivityViewController>) {}
}

struct ContentView: View {
    @State private var showingShareSheet = false
    @State private var snapshotImage: UIImage?

    var body: some View {
        NavigationStack {
            Text("Hello, World!")
            
            VStack {
                Button(action: {
                    self.snapshotImage = UIImage(named: "profile")
                    
                    if self.snapshotImage != nil {
                        self.showingShareSheet = true
                    } else {
                        print("Image not found")
                    }
                }, label: {
                    Text("Print")
                })
            }
            .sheet(isPresented: $showingShareSheet) {
                if let image = snapshotImage {
                    ActivityViewController(activityItems: [image])
                } else {
                    Text("No image to share")
                }
            }
            .onAppear {
                self.snapshotImage = UIImage(named: "profile")
                if self.snapshotImage == nil {
                    print("Image not found")
                }
            }
        }
    }
}

#Preview {
    ContentView()
}

Answer 1

Adding hidden image view with opacity 0 fixed the issue.
import SwiftUI

struct ActivityViewController: UIViewControllerRepresentable {
    var activityItems: [Any]
    var applicationActivities: [UIActivity]? = nil

    func makeUIViewController(context: UIViewControllerRepresentableContext<ActivityViewController>) -> UIActivityViewController {
        return UIActivityViewController(activityItems: activityItems, applicationActivities: applicationActivities)
    }

    func updateUIViewController(_ uiViewController: UIActivityViewController, context: UIViewControllerRepresentableContext<ActivityViewController>) {}
}

struct ContentView: View {
    @State private var showingShareSheet = false
    @State private var snapshotImage: UIImage?

    var body: some View {
        NavigationStack {
            Text("Hello, World!")
            
            VStack {
                Image(uiImage: snapshotImage ?? UIImage())
                    .opacity(0)

                Button(action: {
                    self.snapshotImage = UIImage(named: "profile")
                    
                    if self.snapshotImage != nil {
                        self.showingShareSheet = true
                    } else {
                        print("Image not found")
                    }
                }, label: {
                    Text("Print")
                })
            }
            .sheet(isPresented: $showingShareSheet) {
                if let image = snapshotImage {
                    ActivityViewController(activityItems: [image])
                } else {
                    Text("No image to share")
                }
            }
            .onAppear {
                self.snapshotImage = UIImage(named: "profile")
                if self.snapshotImage == nil {
                    print("Image not found")
                }
            }
        }
    }
}

#Preview {
    ContentView()
}