iOS: File picker cannot be opened in another sheet

[davidsoukup]

I'm trying to implement a file picker for iOS.

I have implemented the file picker function in the View model:

open class SelectFileViewModel: BaseViewModel<SelectFileContract.Event, SelectFileContract.State, SelectFileContract.Effect>() {

    override suspend fun handleEvent(event: SelectFileContract.Event) {
        when (event) {
            is SelectFileContract.Event.SelectDocument -> selectDocument(event.document)
        }
    }
    
        override fun createInitialState(): PepFormContract.State = PepFormContract.State.initialState
    
    private suspend fun selectDocument(document: Document) {
        val files = FileKit.pickFile(
            type = PickerType.File(
                extensions = listOf("pdf", "png", "jpg", "jpeg", "heic")
            ),
            title = null,
            mode = PickerMode.Multiple(5),
        )

        files?.let {
            setState { copy(requiredDocuments = requiredDocuments + (document to files)) }
        }
    }
}

Then, I have this component in iOS.

PepFormFileUpload( onSelect: { viewModel.setEvent(event: PepFormContractEventSelectDocument(document: document)) }, requiredDocument: requiredDocument, selectedFiles: viewModel.state.requiredDocuments[requiredDocument] as? [Filekit_corePlatformFile] )

Selecting files works, but when calling SelectDocument in another sheet, this error occurs:

Attempt to present <UIDocumentPickerViewController: 0x10192ce00> on <_TtGC7SwiftUI19UIHostingControllerGVS_15ModifiedContentVS_7AnyViewVS_12RootModifier__: 0x10202aa00> (from <_TtGC7SwiftUI19UIHostingControllerGVS_15ModifiedContentVS_7AnyViewVS_12RootModifier__: 0x10202aa00>) which is already presenting <_TtGC7SwiftUI29PresentationHostingControllerVS_7AnyView_: 0x10985a800>.

iOS 18.1 & Xcode 16.0

[vinceglb]

Hi @davidsoukup! Thanks for submitting this issue!

Could you share a project that reproduces it? It would be easier for me to replicate your behavior.

[davidsoukup]

It can be easily replicated in sample project, there is code for iOSApp in sample directory to replicate the issue.

import SwiftUI
import KMPObservableViewModelSwiftUI
import SamplePickerKt

struct ContentView: View {
    @StateViewModel
    var viewModel = MainViewModel(platformSettings: nil)
    
    @State private var sheetIsPresented: Bool = false
    
    var body: some View {
        let uiState = viewModel.uiState.value as? MainUiState
        
        // Convert Set to Array
        let files = Array(uiState?.files ?? [])
        
        VStack {
            Button("ShowSheet") {
                sheetIsPresented.toggle()
            }
            .sheet(isPresented: $sheetIsPresented, content: {
                Button("Multiple file picker, only png") {
                    viewModel.pickFiles()
                }
            })
        
            if uiState?.loading == true {
                ProgressView()
            }
            
            Text("Directory: \(String(describing: uiState?.directory?.path))")
            
            List(files, id: \.nsUrl) { file in
                Text(file.name)
                    .onTapGesture { viewModel.saveFile(file: file) }
            }
        }
        .padding()
    }
}

[vinceglb]

Thanks for your sample code. I found that it's not possible to display multiple view controllers at the same time. A common solution is to dismiss the currently active view controller and display the document picker after that.

Here is the result from the PR #170 implementing the changes:

CleanShot.2024-12-11.at.12.54.08.mp4

Does it solve your issue? Is it a problem that it dismisses the first sheet?

[vinceglb]

@theHonzic, what is the best way to manage this case? I'm open to any suggestion!

[davidsoukup]

@vinceglb Thanks for the quick iteration, unfortunately this won't help our case. We have a flow in sheet that requires files to be uploaded in one of the steps, closing the original sheet is not an option for us.

I will leave this issue open for now and try to find a solution during this week.