SwiftUI: Display file url from Array after user Picks file using DocumentPicker - swift

Question

I followed a tutorial on getting Url from a Document a user chooses and be able to display it on the View. My problem now is I want to add those Url's into an array. Then get the items from the array and print them onto the View. The way it works is the User presses a button and a sheet pops up with the files app. There the user is able to choose a document. After the user chooses the document the Url is printed on the View. To print the Url is use this
//if documentUrl has an Url show it on the view
If let url= documentUrl{
Text(url.absoluteString)
}
Issue with this is that when I do the same thing the
If let url= documentUrl
Is ran before the Url is even added to the array and the app crashes
Here is the full code
//Add the Urls to the array
class Article: ObservableObject{
var myArray:[String] = []
}
struct ContentView: View {
#State private var showDocumentPicker = false
#State private var documentUrl:URL?
#State var myString:URL?
#ObservedObject var userData:Article
// Func for onDismiss from the Sheet
func upload() {
// add the Url to the Array
DispatchQueue.main.async{
userData.myArray.append(documentUrl!.absoluteString)
}
}
var body: some View {
VStack{
//If have Url reflect that on the View
if let url = documentUrl{
//Works
Text(url.absoluteString)
//doesntwork
Text(userData.myArray[0])
}
}
Button(action:{showDocumentPicker.toggle()},
label: {
Text("Select your file")
})
.sheet(isPresented: $showDocumentPicker, onDismiss: upload )
{
DocumentPicker(url: $documentUrl)
}
}
}
The main thing I want to do the just display the ulrs into the view after the user chooses the document or after the sheet disappears. So if the user chooses 1 Url only one is printed. If another one is chosen after then 2 are show etc.
This is the documentPicker code used to choose a document
struct DocumentPicker : UIViewControllerRepresentable{
#Binding var url : URL?
func makeUIViewController(context: Context) -> UIDocumentPickerViewController {
//initialize a UI Document Picker
let viewController = UIDocumentPickerViewController(forOpeningContentTypes: [.epub])
viewController.delegate = context.coordinator
print("1")
return viewController
}
func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: Context) {
print("Swift just updated ")
print("2")
}
}
extension DocumentPicker{
func makeCoordinator() -> Coordinator {
Coordinator(self)
}
class Coordinator:NSObject, UIDocumentPickerDelegate{
let parent: DocumentPicker
init(_ documentPicker: DocumentPicker){
self.parent = documentPicker
}
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
guard let url = urls.first else{return}
parent.url = url
print("3")
}
}
}
Not sure if maybe I'm not approaching this the correct way? I looked at different tutorial but couldn't find anything.

Answer 1

Use .fileImporter presentation modifire (above ios 14)
.fileImporter(isPresented: $showDocumentPicker,
allowedContentTypes: [.image],
allowsMultipleSelection: true)
{ result in
// processing results Result<[URL], Error>
}

Answer 2

An observable object doesn't have a change trigger. To inform that the observable object has changed use one of the following examples:
class Article: ObservableObject {
#Published var myArray:[String] = []
}
or
class Article: ObservableObject {
private(set) var myArray:[String] = [] {
willSet {
objectWillChange.send()
}
}
func addUrl(url: String) {
myArray.append(url)
}
}
official documentation: https://developer.apple.com/documentation/combine/observableobject