SwiftUI .fileImporter cannot show again after dismissing by swipe down

Question

I am using the .fileImporter modifier in SwiftUI to import pdf files in my app. I'm having a few issues. Firstly the data is slow to load and often it doesn't load and gives message Internal Error Couldn't communicate with a helper application.

But the main issue is if the modal view is dismissed with a swipe down, it cannot be presented again. Presumably because the binding $showFileImporter is not reset. If the cancel button is pressed to dismiss it works fine. I don't know if there is anyway to force it to fullScreen to get around this.

Here is my code:

.fileImporter(isPresented: $showFileImporter, allowedContentTypes: [.pdf]) { result in
        switch result {
        case .success(let url):
            url.startAccessingSecurityScopedResource()
            if let pDFDocument = PDFDocument(url: url) {
                if let data = pDFDocument.dataRepresentation() {
                    // handle data
                    
                }
            }
        case .failure(let error):
            print(error)
        }
    }

Answer 1

I can confirm my .fileImporter also does not reset the isPresented binding on swipe-down. One way to be for certain is to change your button that presents the file importer from $showFileImporter = true to $showFileImporter.toggle(). On swiping to dismiss the file importer, you have to press the button twice to present again.

Unfortunately this seems to be yet another half-baked SwiftUI thing, but I did find a suitable work-around - handling this case with the presenting button itself:

Button(action: {
if showFileImporter {
    // NOTE: Fixes broken fileimporter sheet not resetting on swipedown
    showFileImporter = false
    DispatchQueue.main.asyncAfter(deadline: .now()+0.2, execute: {
        showFileImporter = true
    })
} else {
    showFileImporter = true
}
}, label: { ... })

I tried just calling .toggle() twice in a row sequentially but needed a slight delay for the trigger to register.

Edit: I also noticed you didn't call url.stopAccessingSecurityScopedResource(), which you should do after calling to your pDFDocument.

Answer 2

The issue persists as of August 2022. I needed to implement Joseph Dvorak's most excellent fix in multiple places so abstracted it on to any equatable binding:

// Usage
$showFileImporter.trampolineIfNeeded(to: true)


// Implementation
extension Binding where Value: Equatable {
    func trampolineIfNeeded(to: Value, via: Value) {
        if wrappedValue == to {
            wrappedValue = via
            DispatchQueue.main.asyncAfter(deadline: .now()+0.2, execute: {
                wrappedValue = to
            })
        } else {
            wrappedValue = to
        }
    }
}

extension Binding where Value == Bool {
    func trampolineIfNeeded(to: Value) {
        trampolineIfNeeded(to: to, via: !to)
    }
}